A first step towards quantifying the influence of the aerosols

The WHO’s snail rate

The key question is not whether or not airborne contamination takes place, but what part of all contamination that is. It will be clear that the WHO/CDC and others, who at first found the airborne infection of little or no importance, are now at most willing to acknowledge that it may have some importance. But it’s not very important and it should and will only be a small part.

Just look at what’s in the Q&A since a few days on the WHO site:

To bring tears to your eyes. So this is what the WHO says 5 months after the biggest global outbreak of a virus in contemporary history. It strongly resembles the reactions in the Netherlands of most virologists and epidemiologists. They remain, at least in public, close to the point of view of WHO/Dutch CDC


The central problem in the discussion about the influence of each of the forms of infection is that all the studies I have come across provide only partial evidence. Where one only sees what one wants to see…

This is also so nicely illustrated by the statements of RIVM (Dutch CDC) and Prime Minister Rutte: In their advice it literally says: “The measures taken are aimed at avoiding virus transmission through large drops, and the measures have an effect. If coronavirus were to spread aerogenic, the 1.5 metre distance measures would have had no effect”.

One forgets that several measures have been taken. Such as banning meetings. It could be that they also played a role or even the most important role or maybe even the only role.


My conclusions

Precisely because, as an outsider, I tried to explain the patterns of spread of the virus through data analysis, I had no preconceived or outspoken ideas about the forms of infection. I all felt that the patterns found simply didn’t fit the mere spread of the virus through larger drops and objects.

And I soon saw in several studies that there were several infectious diseases where the infection was purely airborne. But also that for a long time there were scientists who pointed out the airborne spread of influenza. Like (1), (2) and (3). And also with SARS in 2003 this has been claimed by quite a few scientists. (4 , 5).

The most striking was this find on the Dutch CDC website under the Influenza guidelines.

The lower respiratory tract is the most susceptible to infection, while the preference for upper or lower respiratory tract may vary depending on the subtype of influenza A virus. The minimum dose of infection via aerosols that can enter the lower respiratory tract is very low, in the order of one or a few virus particles. Experimental infection by dripping virus into the nose requires a hundred times more virus, so we assume that infection by droplets and infected hands or objects (doorknobs, telephone horns, keyboards) plays a smaller role.

COVID-19 also strikes mainly in the lower respiratory tract (the lungs). Why, with this knowledge about influenza on the RIVM website, people are sticking so rigidly to the spread of Covid-19 via a larger drop, I cannot get out of the foundations of the WHO or RIVM.

Over the years this discussion has resembled a battle of faith (as between Catholics and Protestants) rather than a scientific discourse. In my opinion, science was the main victim at first. But now the whole world suffers with colossal consequences, as we have already seen in recent months and will see in the years to come with even greater damage.

Unfortunately, therefore, I am not too optimistic about the way in which the WHO will move towards the degree of importance attached to aerosol contamination. Take another look in Northern Ireland to see how Catholics and Protestants still face each other today.


I have just stumbled upon a new study, which gives me more direction in estimating the importance of the different forms of contamination, which points even more to the great importance of the aerosol contamination compared to the contamination via the droplets.

At the end of this piece, you will find these figures.


Before I discuss that study, I briefly describe what I think are the most important findings regarding the distribution of Covid-19, which I have come across in recent months and described in my blogs. You can find them via the table of contents and the search option on this site.

  •  A very large part of the infections in the world took place before the lockdown via super speech events.
  • Covid-19 largely follows the spread pattern of influenza around the world.
  • In houses with a patient, significantly fewer roommates were infected than you would think, based on the assumed danger of infection within 1.5 meters and through objects.
  • Based on the patterns of spread and the studies carried out, the chance of being infected with Covid-19 via surfaces is virtually zero.
  • If you are infected at a superspread event, you will have significantly more symptoms than if you are infected at home. And there are also far fewer people without symptoms.
  • A large part of those with antibodies in the blood have experienced no symptoms.
  • If you get the virus into your nose through drops, it doesn’t automatically mean that someone will get infected for sure.
  • If you get the airborne virus into your lungs through inhalation, you will be sicker than if it gets into your nose through a drop.
  • In all situations a minimum number of virus particles is needed to become infected or ill. (“Viral load”).


The ratio between infection via larger droplets and via aerosols

So the key questions are:

  • How does the virus get into anyone? It’s different with different viral diseases. (HIV is very different from influenza). There are only a few places on/in the body, where that leads to an infection.
  • If it has entered the “right” place then it doesn’t mean that you will definitely be infected by it. It is mainly about the amount of the virus and the way your body tries to remove it. There are several methods for that.
  • And if you do get infected, the question is how sick you get from it. There are people who don’t notice it (asymptomatically) and people who get very sick of it and die. Unfortunately we don’t know the real percentages yet and they depend very much on the age of the infected person. But worldwide we now come across figures that are somewhere between 0.1 and 0.5%.

So it’s about the ratio between the infections via larger droplets and via aerosols.

A recent study provides very important information in this respect: This is the summary of the results:


The main results of this study are, as it is described above the article:

  • The smaller the exhaled droplets are, the more contagious the short distance airborne route is.
  • The speed of ejection has a significant influence on the distance a droplet travels and the change in its size.
  • The large drop route is only dominant if the persons are within 20 cm of each other when speaking, or 50 cm when coughing.
  • The large droplet route only contributes 10% to exposure if the droplets are smaller than 50μm when people are 30 cm apart face-to-face.

This too is a study based on a model with certain assumptions. After all, how many viruses do the droplets with different sizes contain? Is one infected or not if one gets that drop and how many viruses are then minimally needed? But it is in any case a more solid foundation than I have found so far about the large drops and the 1.5 meters.


However, this other study is the first to attempt to quantify how much virus you need to ingest via aerosols to get infected. This depends on the number of virus particles in the air and the duration of inhalation. The key concept here is “quanta”. It is a complex matter, but if you read the study it is good news that with aerosols you don’t get infected after one or two breaths. It depends on how many aerosols there are in the air and how long you are in that environment. This study shows that in many cases it can take much more than ten minutes.


With all this I found this extensive source about forms of diffusion and the importance of aerosols very instructive (it may be more than 10,000 words, but if you have time I would really read it).

Finding the right balance

The big challenge for the world is, on the one hand, to ensure that as few new people as possible become seriously ill as a result of this virus and, on the other hand, to reduce the damage to society (economy, social, public health, etc.) to zero.

Unfortunately, a balance is always needed. Through a complete lockdown, as few new people as possible will become seriously ill, but the damage to society is colossal.

With regard to all kinds of risks in our society we make such a balance. We have more than 600 road deaths in the Netherlands. If we lower the speed limit to 30 km/h on motorways, the number of deaths will decrease by, let’s say, 200.

So by maintaining 100 km/h as the speed limit, we accept those 200 extra fatalities. Or we give people room to smoke, while the number of deaths is therefore estimated at – much more than – 10,000 per year.

We now realise that national lockdowns cause far too much damage. Even local lockdowns should be avoided. But it is also necessary for citizens to be able to properly assess what risks they really run and where those risks are. Because otherwise, their behaviour will be (severely) restricted, with adverse consequences both for themselves and for society (economic, social and public health).

For smart measures, we will need to know how people can really be infected, how high the risks of infection are in various locations and what can be done to reduce those risks. Both on an individual level and in terms of environmental factors.

The attitude of the WHO/RIVM is that it is almost exclusively done through large drops and direct contact. Keeping a distance of 1.5 meters, washing your hands and coughing in your elbow is not only one-dimensional, but is not supported by empirical research. More and more research shows that there is much more going on.

In order to be able to keep that up, WHO/RIVM can only state that people, if things go wrong again, have not kept the 1.5 meter distance. (The ultimate circular reasoning).


This one-dimensionality is in my opinion the reason that the virus is not under control worldwide. And that in Europe, somewhere between October and December, the virus is going to strike again in the same way as it does now in Melbourne. While a month ago in that state of Victoria only a few new cases per day were discovered, this has already risen to 300. This has created a lockdown of the entire state with more than 6 million inhabitants!

Based on all the studies I’ve read, I’m giving scientists a “best guess” of the importance of the different forms of infection and how to minimize the risks.

I think that with this “best guess” in the world, we will make a lot of progress in fighting the virus and maintaining our society.

I hope for a better version of this “best guess” based on the input of experts with an open mind for all that is available. So not based on biased positions. After all, we know only too well how that went for centuries with the struggle between Catholics and Protestants.


My best guess is:

  • 75% of all infections happen at so-called super-spread events. These are gatherings where 5 or more attendees are infected. They take place in closed rooms with little or no fresh air. This also includes infections that pass through an HVAC system, in which the virus particles are spread over all areas of the building/complex. I estimate that more than 99% of these contaminations occur via aerosols.
  • The other infections take place per person, as it were. (With sometimes more than one at a time). This can be done in three ways:

o You get a drop of an infected person in your nose/mouth/eye. This can happen with coughing/sneezing and talking, but only at a very short distance.

o If an infected person coughs / sneezes / talks and you are at a short distance, you breathe in the aerosols for a while, which are released during the coughing / sneezing / talking.

o You spend some time alone or with a small number of people in a room where aerosols have been released into the air by that one patient, and you become infected.

Of course, in care situations (hospitals, care centres) the above occurs relatively more often than in a normal home situation.

My best guess for these three variants (i.e. based on the number of people infected) is:

  • Via a drop of an infected person in your nose/mouth/eye I estimate 2%.
  • By breathing in aerosols at a short distance for a while I estimate 8%.
  • By breathing in aerosols for a while I estimate 15%.

Based on this best guess I will come up with a document one of the coming days, where everyone can read what to do in specific situations based on the actual risk and the risks you are willing to run.

This is much more than the 1.5 meter doctrine, as I have already shown in this piece.

How you get infected by aerosols and what you can do about it

Fortunately, due in part to the publicity surrounding the letter from the 239 scientists to the WHO, more and more people are recognizing that aerosols are an important source by which people are infected. On April 2nd I wrote this about it and on April 18th I spoke about it at Op1. Superspread events are the driving force behind the pandemic and I have shown here that the vast majority of the infections are related to it.

Studies and logic show that with superspread events, it just can’t be otherwise that airborne infections were the cause. This database contains 500 of these events worldwide, each one infecting more than 100 people.  It is completely illogical to think that these people have been infected via direct contact with an infected person.

Prof. Streeck’s research in Heinsberg also gives strong indications of this.

The fact that 10% of the infected people account for 80% of the infections, 20% for 20% and 70% for 0%, as established by Adam and Cowling, leads to a number of important conclusions:

– Apart from superspread events, the risk of being infected is not so great. Contact studies worldwide show that only 10% to 35% of the housemates of infected people are infected. So the vast majority of housemates are not infected by a patient at home.

– At superspread events, many are infected at the same time, and the research in Heinsberg shows that you then become much sicker than if you were infected at home. (There they had 1.6 times as many symptoms and at home 36% of the infected persons had no symptoms at all and at Carnival 16%).

In fact, there are three possible routes of infection. The above figures, but also many other studies on Covid-19, as well as animal tests carried out with influenza, indicate the following:

– The chance of being infected by touching surfaces on which a patient has left the virus is (very) small. In any case, much smaller than many people in the Netherlands think. (The American RIVM has also scaled down this threat).


– The chance of being infected because an infected person coughs, sneezes or otherwise releases the virus in your face within 1.5 meters, sis much smaller than many people think.

First of all, the droplet(s) have to float in a place where the virus can strike the other person at all (and that is the nose in particular). And that chance is really not as big as this study shows.

Then the virus must be able to multiply in the body. And it is stated in the literature that it is really not the case that, if the virus has gotten into the nose, one will certainly get sick. On the one hand, it may be that the body removes the virus in the direction of the esophagus. On the other hand, if there are too few virus particles in that drop, the body may be able to repel the attack of the virus. Wells showed this already in 1955.

That this is the case is supported by the observations, that apparently 70% of people do not infect anyone else. So even if you spend days together with a patient in your household, the vast majority of those housemates are not infected yet.


– The dominant way to get infected is by air and there are more and more studies that say so, like this one. I myself think I can show that this is in 95% or more of the cases. But even if you think it is only half, like Prof. Christian Drosten, the advisor of Merkel, the following is equally important.

WHO/RIVM maintain, that aerogenic contamination is very rare, but that just doesn’t fit the phenomenon that during superspread events so many people are infected at the same time.  And realize that a superspread event is already classified as such when more than 7 people are infected in a location at about the same time.

And if you still think that the aerosols are unimportant, you can stop reading here.


Already in 1955 Wells showed that the inhalation of aerosols by laboratory animals, to his own surprise, led to much more extensive damage to lungs than if it went via larger droplets. His explanation is very logical.  If the disease mainly affects the lower respiratory tract (the lungs), which is the case with Covid-19, and the virus that enters the body nestles directly in the lungs, then that is the best place for the virus to strike. (A virus like HIV strikes in a completely different place and is transmitted in a completely different way).

You often notice that people think that if you only come into contact with one particle of the virus, you will automatically become infected and become quite ill. Luckily, that’s not true. The human body is built to repel all kinds of “attacks” of viruses and bacteria and usually does that very well. But sometimes that attack is so big for the body that it doesn’t succeed in repelling it. This has to do with the size of the attack as well as the condition of a person’s body to repel it. And that also makes a difference per disease.

For Covid-19 we now know that a large number of people have built up antibodies, without noticing any symptoms of the disease. Exactly what this figure is, is still under discussion, but seems to be somewhere between 30 and 50%. (In the meantime, the WHO has indicated that people without symptoms are apparently not able to infect others either).

What the exact ratio is between being infected and dying is also not yet known. But after figures of 3% from the RIVM, you now see figures that are (well) below 0.5%. And then it’s mainly people over 70 and mostly with underlying suffering. Of the people in the Netherlands who died from this disease, less than 10% were younger than 70 years of age (and most of them had underlying suffering).

This is very important to realize, so that you also better understand what risks you do or don’t run.

The crucial concept in aerosol contamination is the “viral dose”; the number of infectious virus particles needed to infect another person. That number is not known, but for the purposes of the explanation below, let’s link a number to it. Let’s say that 1,000 infectious virus particles are needed to infect person A in his lungs in such a way that he gets symptoms of that disease. (For person B this can be a higher or lower number).

Two components are then important to reach that number of 1,000. How many infectious virus particles are in the air of the room where you are present and how long you spend in that room. This can be found in the interesting article by Prof. Bromage.


So if you inhale 10 infectious particles per minute then you have to inhale 100 minutes to reach that limit of 1,000 virus particles. If you breathe in 20 per minute, you reach that limit after 50 minutes.

Now there is good news: if you watch superspread events, there are strong indications that you have to be present for a while and breathe in the virus before it can make you sick. Even in places where you might think there must have been quite a bit of virus in the air, it seems to have taken more than half an hour to breathe in enough virus to get sick.  (But as I said, that also makes a difference per person, because the elderly will have reached that limit sooner than the young). And in places where there has been little virus in the air, it would have taken (much) more than 1 hour to become ill.

With that as input we can both indicate a policy to ensure that this form of infection is prevented as little as possible, and what approach you should follow to ensure that you are not infected in this way.


Preventing this type of infection

These are interior spaces where many people are present at the same time, who normally don’t meet each other or don’t meet often. This does not apply to yourself at home, if no strangers come there. In the latter case, however, there are precautions to take, which I will mention at the end of this blog.

– Make sure that the air in a room is refreshed as much as possible. Then the virus particles will be expelled. This can be done by good ventilation (windows / doors open against each other and / or an HVAC system that brings in a lot of fresh air).

– Adding something to an HVAC system that removes the virus from the air: (filters or other tools. (That’s why I propose a Delta Plan Ventilation, both to ensure sufficient fresh air and to take the virus out of the air).

– If the above cannot be done (well), then make sure that the people present in a confined space don’t or don’t bring a lot of aerosols into the air. This means applying restrictions with regard to singing / shouting / talking and/or wearing mouth protection.

– Research has also shown that if the relative humidity in that room is somewhere between 40% and 60%, the virus will float in the air for the shortest time. This can be seen on this site where doctors call for this humidity to be maintained.

However, it is important to take into account that the danger can only arise if there is someone present who is contagious. That is someone who is infected himself, perhaps asymptomatic, but who apparently feels good enough not to stay at home.

At the moment in the Netherlands there are – fortunately – very few such people, so the risk of being present in a room, where you can breathe in contagious virus for a while, is very small.

Be aware that in the slaughterhouses the major outbreaks have come mainly because people work in places where the temperature is kept low – below 10 degrees – and there is little ventilation. This combination is the ideal condition for the aerosols to stay in the air for a long time.  The present outbreaks in warm countries where many air conditioners are used, such as the southern states of the US and various countries in the Middle East, are also strongly related to this.

In the autumn, there is a much greater risk in the Netherlands that there will be situations where the virus is in the air to be inhaled. This is due to the colder temperatures and lower humidity (in grams of water per kilo of air). And that human activities will go more indoors. That was the situation with the large outbreaks in the Netherlands that occurred in the 4 weeks after 25 February. Recognize that based on the number of hospitalizations at the end of March, the number of new infections per day must have been between 25,000 and 50,000.

And where a large proportion of the residents of care institutions have become infected, it is more likely that this has happened because the virus has been distributed to the residents via the ventilation system than it was because infectious people without mouth protection have come into contact with the residents.

The proposed Delta Plan Ventilation serves to ensure that the conditions that could lead to superspread events in the coming winter will disappear from the Netherlands.


Preventing yourself from becoming infected

Until the end of September, the risk of being in a room in the Netherlands with someone who can infect others is very small. But after that, that chance will clearly increase.

If the Ventilation Delta Plan would be carried out, we would know which confined spaces are Corona proof. So there is no risk of being infected by aerosols in those areas. All activities can therefore take place there normally.

If a room is not Corona proof then there are a number of important points to take into account.

– Keep windows or doors crossways open, allowing fresh air to come in from the outside and the aerosols filled air to flow out.

– If this is not possible:

Ensure that all persons present wear mouth protection (as in public transport).

Make sure you don’t sing, shout or talk a lot.

Don’t stay too long in that room and (especially if you belong to a vulnerable group) wear mouth protection yourself.

The more rooms that are Corona proof, the less normal life is hindered and the lower the risk of outbreaks, with all kinds of undesirable consequences (such as regional lockdowns, etc.).

That’s why I think it’s so important to start with that Ventilation Delta Plan, in which all interior spaces with HVAC systems can be given a Corona proof stamp, which is also visible to those present. So that they know what their risks are and how they can behave there.

The home situation

Aerosols can also play a role in the infection at home, but then of course there is a very important condition: that there is someone at home who can infect others.

That will be so little the case by now, that you won’t have to worry about this virus in the air when you’re alone with your housemates.

Only when others enter your home, especially in autumn or winter, is there (slightly) more risk. You can reduce that risk by providing fresh air and/or bringing the humidity to a level between 40% and 60%.

And if you are still worried, don’t make the time spent together too long, or wear mouth protection. Or do the activity outside (in the garden, on the balcony, in the park).

Caring for the expulsion of air by fresh air from outside is the best strategy here.

Keep trying to realize how small the risks are. Especially in the coming months. You will ruin your own life if you are constantly afraid of something for which the chance of it happening is so small. Because even if you become infected, the chance that you will become very ill or die is also small. I have older people in my circle of acquaintances who are so afraid of being infected that I think that that fear is a greater risk to their health than the real risk of becoming very ill or dying of Covid-19.

By knowing how big/small your risks are, in which places and when your risks are bigger and smaller, you can best live in a world where Covid-19 will be among us for quite a while. (Especially if WHO/RIVM persists in not taking the right measures to prevent infections).

Covid-19 has the flu

It is becoming increasingly clear that Covid-19 has the same distribution patterns as influenza. We can learn a lot from this, if we are prepared to take a serious look at the data. Plus, we also know that it will lead to far fewer infections throughout Western Europe and North America in the coming months. (And it may reappear in the autumn).

The large outbreaks above 30 gr North latitude

The major eruptions of Covid-19 between January and mid-April have been in the areas where the flu waves are only in winter.  (Only above 30 degrees North latitude flu waves, only occur in the winter months. South of it we see different patterns. Then it is during rainy seasons). The big flu wave in 2017/2018 in the Netherlands lasted until week 20 (so beginning of May).

This is the overview of the flu in the Netherlands over the past 5 years.

Above 30 gr. NB in China, the annual flu wave is between December and March.   Wuhan is also located in that area.

When comparing the spread pattern of influenza and Covid-19 two points are of great importance to take into account:

  1. In the case of influenza, with every annual variety that flares, a significant proportion of the population is already immune to it, due to comparable variants from the past. This is not the case with Covid-19.
  2. Normally we see the influenza virus in Western Europe and the northern part of the US already at the beginning of the winter. That takes until somewhere between weeks 10 and 15.  The flu wave of 2017-2018 lasted very long (about 16 weeks). Covid-19 only appeared relatively late in the winter (around week 6).  16 weeks added up to week 22 (that week ends at the end of May).

By zooming in on the flu wave of 2017 -2018 and comparing it with the figures we now have for Covid-19, the above can be well illustrated.

In addition to the excess mortality numbers for the flu period 2017-2018, respondents were asked via Peil.nl at the beginning of May 2018, whether they had flu in the past 8 months. Based on the answers, we estimate that this percentage is 25% for people under 65 years of age and 15% for people over 65 years of age.

If we combine these figures with the excess mortality per age group in 2017-2018, you can estimate what the IFR has been during the flu wave that year. The IFR is the percentage of infected people who died from that disease. (Infection Fatality Rate).

We can also do that with the mortality of COVID-19 up to and including week 18 (these are the figures established by CBS). The accountability for the IFR, which we use, can be found here.

And then we see the following:


If we only look at the totals per age group, the similarities are very striking (the last two columns). The IFR per age group for influenza in 2018 and Covid-19 are quite similar. Only if we look at the gender breakdowns, we see that men die more of Covid-19 than women.

Apart from the difference in the way COVID-19 spreads compared to influenza, it is important to realize that in case of influenza in 2017-2018 100% of the cases were counted. Those who did not become ill were apparently immune to that year’s influenza variant(s). With respect to Covid-19 this is certainly not the case now. It is estimated that the percentage infected with Covid-19 until now is somewhere between 10 and 15%. So it is plausible that if Covid-19 could spread indefinitely, the total excess mortality will be a factor of 5 to 10 greater than the approximately 9,000, which have been established up to week 18.


Is Covid-19 going to follow the same pattern as the flu waves?

The central question now is whether Covid-19 will follow the same seasonal patterns as influenza in terms of spread. It seems so, because everywhere above 30 degrees North latitude where Covid-19 has broken out you see it descending sharply, like influenza does.

FT.com shows that nicely with the following graph.

With these figures it should be taken into account that the death of Covid-19 occurs on average 3 weeks after the infection. So the current state of affairs on the graph shows the number of infections around 25 April (end of week 17).

The sharp decline in the number of deaths in Western Europe and New York since April 15th, which we actually see in this overview, is assumed to be due to the lockdowns that have been applied everywhere in various variants. (Personally, I think I can prove that the most important reason was that meetings with more than a few people were banned everywhere around 15 March, but that is irrelevant in the context of this article).

Influenza no longer spreads in Western Europe after week 18 to 20. Apparently the conditions for the influenza virus are not favorable then. Does that apply to COVID-19 as well?

There are many indications that COVID-19 follows the pattern of influenza in its spread.

I want to show that indirectly through the information about Brazil. This report gives an overview of the Brazilian flu waves. The country is very large. It runs from 5 degrees north latitude to 33 degrees south latitude. This graph from the report shows when the flu waves occur in the different states of the country.

Vertically you see the latitude. Horizontally the week number. The orange line refers to states in Brazil where there is a clear moment in the year when a flu wave starts. The gray line refers to states where there is no clear seasonal pattern. But also there we see that the flu waves in Brazil run between week 14 and 26 (so from mid-March until the end of June).

The upper orange line concerns the Amazon province, where Manaus is located. The flu season starts there in week 17. The flu waves come a bit later in the southern states. Rio de Janeiro is between week 22 and 24 on average. Sao Paulo (in grey) is around week 21.

Because Covid-19 didn’t “meet” any people in the beginning, who were already immune, it’s logical that it spreaded more easily. That happened in Sao Paulo around week 8. Especially rich Brazilians who had been on winter sports in Europe brought the virus into that area.

The outbreak in Manaus started around March 20.  I wrote about it in this blog.

The current developments in Brazil are pretty much in line with the influenza pattern (if you take into account that it can spread more easily than any influenza virus, because nobody is immune to it).


Below I’ve made a graph with the normal flu seasons in 4 countries in the southern hemisphere plus Italy and England. It shows the number of deaths by Covid-19 per 1 million inhabitants. The difference is obvious.

If we look at the top 10 countries in the world with the largest number of deaths by Covid-19 per 1 million inhabitants, those are all countries, like the Netherlands, where the flu wave is in the winter (as can also be seen in the graph in the two lowest countries). The official number of COVID deaths per 1 million inhabitants is (well) above 200 in those 10 countries (in that overview I have excluded very small countries).

The fact that the figures in New Zealand, Australia, Argentina and South-Africa are so much lower than ours, must be related to the fact that in those countries there was no flu season (yet). Therefore the conditions for the COVID virus to spread were significantly worse there than in our country, just like with influenza. Here I explain why.

My conclusion is that in the coming months Covid-19 will follow the patterns of flu worldwide.

(With the note, of course, that because few people in those countries are still immune, this will lead to a higher spread rate if the right measures are not taken.)


The major consequences of this dispersal pattern

I draw the following important conclusions here:

Circumstances to spread again quickly will be (very) unfavorable for COVID-19 until sometime in the autumn. Regardless of what measures we take, the number of people infected will no longer increase significantly. Even if we do almost everything this summer that we were allowed to do before March 1st, it will certainly not see the large numbers of victims that we had at the end of March in the Netherlands.

If in countries below 30 degrees North the COVID-19 virus has not yet completely disappeared, there is a very good chance that when the normal flu season starts there will be major outbreaks.

With regard to the latter, I am very worried because WHO/RIVM are on the wrong assumptions with regard to the way in which one person can infect the other. (Namely through direct contact, completely ignoring the airborne infections through aerosols). This document by the RIVM of May 18th is sad proof of this. I can’t believe my eyes, how they are working towards their desired mantra/final conclusion.

If you don’t have to believe me, read this paper by the Australian professor Lidia Morawska. The title is “Airborne transmission of SARS-CoV-2: The world should face reality.” This is her conclusion.


Remember that in India for example, the monsoon period starts at the beginning of June. It starts in the Southwest (Kerala), where it can stay up to 5 months and then moves to the Northeast. In New Delhi it starts in July-August.

As long as the WHO does not recognize how the spread of COVID-19 really takes place, countries will take the wrong measures.

In the Netherlands through the 1.5 meter measures, with disastrous consequences for economy and society. (and also unnecessary health risks in indoor areas)

In countries where the rain season has yet to start, with vastly more COVID-19 victims than needed.

Hopefully WHO and RIVM will return from that road, leading to a disaster much bigger than necessary.


I’m not a virologist or an epidemiologist. I was trained as a scientist. Graduated in 1971 and worked for a number of years as a scientific assistant at the University of Amsterdam. My specialization is research and statistics. I learned to program in 1965. I’ve been working on (big) data analyses for a long time.

I am good at analyzing data, recognizing patterns. I am also good at logic. Was a real Math-type at school. Also good at reading and assessing scientific studies.

From the end of March I wrote articles on this site about Covid-19. By analyzing data, reading the latest international scientific studies and logical reasoning, I have drawn a series of conclusions. In the meantime some of them are either generally acknowledged or caused discussions, which eventually come to the same conclusions as I drew then.

(If you have time, I invite you to read my article of April 14th with the title “This is how the spread of Covid-19 is going” and the article of 24 May with the title “The Covid-19 knowledge of today”).

Let me now turn to the separate conclusions I drew in my articles and to what extent these conclusions have now become more mainstream:


  1. Mouth protection in public places

On March 30, I wrote this article “Why wearing face masks is the only logical conclusion for now”.

On 5 June the WHO advised to wear mouth masks in public places.


  1. Ventilation and higher humidity can be used to prevent spreading in enclosed spaces.

From the first blogs on March 27th I wrote about the influence of humidity on the spread of the virus. On April 2nd in the article: “Yes! These are the spread accelerators; the micro drops”, a number of things came together. I described in it that you could prevent infections by increasing the humidity and ventilation.

In a country like Japan this was already known for a long time, but in the Netherlands the RIVM (CDC) stayed away from it for a long time. But the ventilation component is (fortunately) finally starting to become more common in the Netherlands. Increasing the air humidity can also be seen in many places as an aid against spreading. However, as long as the RIVM (CDC) does not yet recognize the impact of the airborne virus, it is not yet an explicit policy in the Netherlands.

  1. Outside there are far fewer risks of infection than indoors.

In several articles in April I indicated that the infections mainly occur indoors. After the outcome of a number of investigations, I explicitly stated in my article on 25 April that people should go outside much more.  I also mentioned this Chinese study about the locations of infection, which is recently widely quoted in the media as a substantiation for the much smaller chance of being infected outdoors.

About 1 month after my article, some of the usual suspects (virologists and epidemiologists on Dutch television) that the chance of being infected outside is significantly smaller than inside.

  1. Surface contamination does not occur

In my article of April 14th  with the title: “This is how the virus spreads” I described that the chance of infection through objects is very small.

On 22 May, the American CDC revised its advice and reported that the transmission via objects is not as great as had previously been assumed. Prof. Streeck’s study in Heinsberg subsequently came out, in which he was unable to collect virus particles from objects in 21 households, which were also capable of infecting people in further laboratory research.

  1. The major role of superspreading events in the spread of the virus

On April 9th I wrote an article about the great importance of the superspreading events. And on April 19th  I went deeper into the superspreading event of Kessel on 5 March.  That led to this article of April 24. Based on the numerical analysis of individual municipalities until the moment of lockdown, I couldn’t help but conclude that the superspreading events played a dominant role in the spread of the virus. And that without such an event, the virus actually spread rather slowly. Because while we were still living our normal lives before the lockdown and social distancing, you could clearly see that in the figures of municipalities where no superspreading events had taken place.

On June 3rd I described the approach in Japan and an article in the New York Times entitled “Stop the superspreading events”. Research in various countries confirmed my conclusions of April 24th .

  1. The important role of aerosol

From April 2nd I drew attention to the major role of aerosols in the spread of the virus. Indeed, I could not imagine that during meetings with many people, even if all precautions were taken, super spread could take place in any other way than by air.

That evidence was provided by the study of Prof. Streeck in Gangelt. I described that in this article on May 4th . If you look broadly at the figures, almost all Covid-19 infections seem to be airborne, as I described on June 3rd.

There are more and more prominent virologists pointing out the importance of the airborne spread of the virus. This was for example the podcast of Prof. Christian Drosten in which he says the following: “Droplet transmission is more likely to play a smaller role than the transmission via aerosols”. On June 10, a new study was released called “Identifying airborne transmission as the dominant route for the transmission of COVID-19”. The title says it all. Another additional proof of the central role of the virus floating in the air.

In the Netherlands the RIVM (CDC) and the Outbreak Management Team (for the time being) hold the opinion that that role is not there or very small. Unfortunately, however, these Dutch experts prove time and again that they are behind the facts. (Take, for example, the discussion about mouth protection, in which Van Dissel, the chairman of the CDC, even after introducing mouth masks in public transport, said in public that it was unnecessary. I am curious what he will say now, now that the WHO has also changed its mind when it comes to mouth protection in outdoor areas).

Although there is increasing international recognition that airborne contamination could play a major role, this is not (yet) the case in the Netherlands with the official authorities.

But now that the German RIVM (RKI) also recognizes aerosols as a way of contamination and even a professor has come to EenVandaag to draw attention to it, a check symbol is added to this section as well.

The RIVM’s reluctance to recognise this is dramatically linked to the following point.


  1. The 1.5-metre society is unnecessary and unsafe

From the moment the Dutch Government announced the 1.5 meter society as the new normal, I have resisted this in different ways. And through my cooperation with www.smartexit.nu I also operationalized it in another way.

In essence that objection is twofold. On the one hand, it causes considerable economic and social damage. For that reason alone, I strongly oppose the proposal to formalize the 1.5-metre society by law. On the other hand, it is also not the right answer to the real danger of the large-scale infection with the virus. 80% of the infections take place via superspreading events. And that doesn’t happen, I note here, because people don’t stay 1.5 meters apart, but because of the floating virus in the air, which is inhaled by those present for a longer period of time.

So the 1.5 meter does not prevent the majority of the infections, and also provides a false certainty. In Georgia, for example, we see that after the opening of churches where people held tightly to the 1.5 meters, contaminations occurred again.

But at this point there is a huge obstacle, of which I’m afraid that as a large block of concrete it keeps our society (both economically and socially) deep under water and thus destroys a lot (unnecessarily).

That obstacle is, that almost all virologists and epidemiologists assume that influenza spreads through droplets and that this also applies to Covid-19 (and SARS). This is how they are trained and how they look at the spread of these infectious diseases. This is also reflected in the attitude of the WHO (and RIVM (CDC), and Outbreak Management Team). People hardly want to think about any other way of spreading these infectious diseases. Let alone that it plays a dominant role. Because that has colossal consequences with retrospective effect. Quite a lot of the work done in the past in this field suddenly loses its basis.

The 1.5-meter society (social distancing) is the consequence of the fact that you state that people are infected almost exclusively through direct contact. If the contamination occurs mainly (or almost exclusively) through the air, then this 1.5-meter society is not necessary and we have to take other measures. (And that actually only concerns ensuring that superspreading events cannot take place).

That’s why you see the pattern that 99% of virologists and epidemiologists, no matter what conclusions they draw, always end up with “and by the way we believe that people inside or outside, social distancing should be kept”. To my ears, it gradually sounds like a kind of desperate attempt to sustain what can no longer be sustained, that the infection of Covid-19 (and influenza) occurs almost exclusively through direct contact.

And most politicians are therefore so hypnotized (under the influence of the Bergamo trauma) that they repeat these mantras thoughtlessly. It doesn’t matter that the facts show that there is no increase of new infections when deviating from the 1,5 meter distance (like during the beautiful Easter weeked and that beautiful Ascension Day). And it doesn’t matter that there are hard indications worldwide that the outbreaks in slaughterhouses are due to the low temperatures, which encourages the long exposure to aerosols. It must and will be the deviation from the 1.5 meter/sociale distancing measure or some alternative explanation outside the workplace. It should therefore have happened in the residential complex and commuter traffic. Or not in aircraft, but elsewhere at the airport. As long as one can keep one’s own mantra of the 1.5 meter distance.

As an extension of this, we see that while a package of measures has been taken such as “stopping meetings of larger groups of people”, “closing schools” and “social distancing/1.5 meters”, the clear decrease in the number of infected people is purely attributed to the latter measure. Mentally, for them it is not even conceivable that it could be due to the first measure alone.  Especially when we now know that people are infected so much less at home than during a superspreading event.

The only way I can place this, is by comparing it with the beginning of the 17th century. Everyone was convinced that the sun revolved around the earth. Galilei came and claimed it was the other way around. That was too much of a paradigm for the clever minds of the time. And Galilei ended up under house arrest.

The fact that in the end it took a while before it was admitted that Galilei was right did not harm the course of human history.

But every day that it takes longer to face the fact that the virus spreads (mainly or only) by air and that the 1.5 meter society does not protect us, the more the enormous damage is done.

The fact that the experts involved (RIVM, OMT, virologists and epidemiologists) can comfortably maintain a position that has become virtually untenable on logical grounds and the latest research results, is due to the fact that the media let them debit their old mantras without any critical questions. And hardly any attention is paid to counter-arguments.

Media, who do not play their role critically and constantly invite the usual suspects to debit their mantras. And we have politicians in and around our government, who apparently have been hypnotized at one point or another. All they can do is to repeat “keep 1.5 meter distance wherever you are”.

Hoping the ship returns to shore safely, but then I’m afraid the ship is already sinking.

DeltaPlan Ventilation

(The term DeltaPlan originated in the Netherlands after the great flooding of the Delta of the Netherlands – the south-western part – in 1953 with almost 2000 deaths. It was an integral plan to ensure that this would never happen again. Since then it has been used to refer to large integral plans).


While I was writing this part the message came from the lockdown in Gütersloh, due to the big outbreak in a slaughterhouse. That’s exactly where I’m afraid it will happen – especially in the autumn – in the Netherlands, because WHO and RIVM (the Dutch CDC) continue to deny the -large- effect of aerosols. However, outbreaks do occur and society has to lock up for a while.

This is Koen Swinkels’ database of approximately 1,200 superspreading events around the world. 500 of them concern more than 100 people who became infected during an event.  It is far from complete, but only includes the officially registered superspreading events.

There is a commonality: these events took place in more or less enclosed spaces, without a sufficient supply of fresh air.

The Van Dissels of this world, following in the footsteps of the WHO, continue to claim that also on those occasions the contamination took place via direct contact. If only 1.5 meters distance would have been kept, these contaminations would not have taken place.

Nearly 2 months ago I described in this blog that the major outbreaks in the meat processing industry were due to the fact that the virus can remain in the air for a long time in factories where low temperatures are maintained to ensure that the meat does not spoil.

But no, when it finally broke out in the Netherlands, it had to be because of the living conditions of the workers. Something that was also supplied in other countries.  In this blog last month, I already indicated what major consequences that could lead to, as long as you don’t recognise the real problem. And that is exactly what happened in Gütersloh.

The director of the German RIVM reported yesterday for the first time in the German ZDF journal that aerosols at a low temperature in those slaughterhouses is the cause.

If these conclusions had been reached 2 months ago, the outbreak in Gütersloh would not have taken place and the Lockdown would not have been chosen.

So now we really have to do the best we can, in order not to get similar situations in the Netherlands. And those risks will clearly increase when we enter the autumn (And I don’t completely rule that out during the summer either).


Delta Plan Ventilation

The virus thrives best in confined spaces without good ventilation, where people are together who normally do not (often) meet. Low specific air humidity (below 6g/kg, which at 20 degrees is less than 45% relative humidity) ensures that the aerosols can remain in the air for a long time and then be inhaled. Of course, it is crucial that there is someone in that room who is contagious. And during this summer the chance of ending up in a room with a contagious person will be extremely small.

Natural ventilation, for example two windows / doors that are open opposite each other, provide the supply of fresh air and the removal of air with possible virus particles. During the summer we often have such situations, in order to dissipate the heat. But when it’s colder outside, we don’t do that.

At home this is much less of a problem. Especially if you don’t have others visiting you or people you deal with very regularly. Then the risks are virtually zero. But if you go to a place where there are a lot of people you don’t meet or hardly ever meet, the risk increases. And certainly in autumn or winter.

For buildings where the temperature and ventilation are controlled by HVAC systems (and there are many of them), these systems spread aerosols between rooms.  This is a considerable risk at care institutions, for example. And I think that the vast majority of victims in care institutions are infected in this way.

But that risk concerns every place where many people are together: school buildings, offices, cinemas, theatres, event venues, churches, association buildings, shopping centres, hospitals, restaurants.

But at the moment, the good news is that there are now very few people in the Netherlands who are contagious, so there is only a very small risk of infection in any of those buildings. And also, that there are already quite a few HVAC systems, which are set up in such a way that those flying virusparticles don’t get stuck for long and are removed. Those systems are Coronaproof. That depends, among other things, on how much fresh air is drawn in from outside the system and on the quality of the filters in the system.

Plus, there are also many buildings where the virus does not easily get stuck above people. For example due to high ceilings (large volume of space compared to the number of people) and/or how the ventilation system works. For example, I understand that the system in the ceiling of the Concertgebouw’s main auditorium is effective in expelling those harmful aerosols.

I myself knew little about HVAC systems, but there are several good experts who provided me with relevant information.  I gave one of them the space to write an article on my blog.

I received information from someone who had been inspecting those HVAC systems at the Labour Inspectorate for years, which made it clear to me what the core of the problem is. And it’s twofold:

  1. When setting up the HVAC systems, one of the issues is how much fresh air is sucked in from outside. The more that is, the better that is in terms of reducing the chance of being infected.

There is an important term “ventilation rate”: the amount of fresh air sucked in per hour divided by the volume of the total room. If the ventilation rate is 2, then the air in that room is completely replaced 2 times per hour.

Remember that if it is colder outside than inside, the HVAC system has to heat that air. And if the air is warmer outside than it is inside, the HVAC system should cool the air properly. In both cases this costs (a lot of) energy.

So the tendency will be to recirculate the inside air as much as possible, instead of sucking in fresh outside air.

That expert told me that in practice the ventilation rate is usually kept undesirably low in order to keep energy consumption low. That would especially be the case in slaughterhouses. Because the temperature has to be kept low there, all the air from outside that is warmer than the desired indoor temperature has to be cooled down considerably.

Increasing the ventilation rate by 2 or 3 can, on the one hand, result in considerable additional costs. He also told us that he regularly came across HVAC systems that simply don’t have enough capacity to bring the temperature down enough.

  1. In addition, suppliers of HVAC systems claim that they can render viruses harmless by means of filters and/or other air purifiers

I can’t judge it properly, but I’m sure that it shouldn’t be difficult to determine very quickly with a task force which of those products/services conclusively succeed in rendering the virus harmless via HVAC systems and which do not.


To really ensure that there is no large second wave in the Netherlands in the autumn and to prevent measures also having to be taken, as is currently the case in the Gütersloh area, we need to set up and implement a DeltaPlan Ventilation.

This is much more important than the 1.5 meter protocols of all kinds of companies and industries in order to prevent the spread of the virus.

Every HVAC system in the Netherlands must be made Coronaproof before the end of October. They must be modified if necessary, or certain additions must be made to comply with the qualification “Coronaproof”.

If that is the case, then everything can be done within those buildings without any restrictions. (I’m sure one shouldn’t have to keep 1.5 meters there either, but that’s of secondary importance for now).

If that is not the case, then there are a number of possibilities to still be active in those buildings:

– Windows / doors open to a large extent.


– The mandatory wearing of mouth protection if you are/will be in that building for a long time


– It is established (especially if there is a large volume of room in relation to the number of attendees, for example by a high ceiling) that the risk of the virus remaining just above the heads of the attendees is small.

We only have 4 months left to implement this plan. In fact, we have already lost time, because the RIVM denied/ denies that this is important. Ventilation hardly plays a role in the RIVM protocols that have been issued so far. (As I know from my contact with my daughter’s primary school). It is almost only about the 1.5 meters and personal hygiene. And read this again, only 1 month ago.

Every day that the RIVM still refuses to put this subject on 1, is an extra day, which may result in extra casualties in the Netherlands in the autumn and winter. that increases the chance that we will end up in certain lockdowns after all.

So my concern is not only that ventilation should be set to 1, but also that the Delta Plan for the HVAC systems should be introduced in the Netherlands immediately. Perhaps the people who are now active in removing houses from the gas can also become temporarily active in this Delta Plan.

And I sincerely hope that the experts I have contact with will be able to play an active role in the design and implementation of this Delta Plan. Because when I read how things went in the first few months with mouth caps, respirators, etc., I am afraid that we will only have started when winter arrives.

I hope that those who are responsible for locations with an HVAC system will also take their own responsibility. And don’t hide behind the fact that it’s not (yet) in RIVM protocol. Even with simple means, a lot can be done in the short term, especially with the nice weather outside.

So ventilation, ventilation, ventilation.

Wells proved it already; it’s the airborne microdroplets

Wiliiam Firth Wells, with his research from the thirties, would have provided the basis for the approach to social distancing, to keep the distance of more than 3 feet.

I was curious and tried to find his 1955 masterpiece. “Airborne contagion and Air Hygiene” with a description of all his scientific work

It took a lot of effort to find that 1955 book, but now I have it and it’s more than worth it.

It’s about the work Wells has done since 1930 on the contagiousness of all kinds of diseases, with reports of many experiments. It’s a kind of handbook, and rightly so. It’s amazing what that man has done in those 25 years. If he’d still been alive, the world would have been a much better place and hundreds of thousands less people would have died.


When I looked in Wells’ book for that “empirical rule of thumb” of keeping your distance, I was astonished. It was just research into how far larger droplets spread when they come out of a person’s mouth or nose. And yes, most of them end up on the ground within 3 feet. But in no way was it determined whether someone was infected when they got those drops from a short distance.

It was something like measuring how far the best golfer can hit the ball. That’s over 400 meters. But that doesn’t mean the ball will end up in the hole. You have to determine that separately. And Wells didn’t do that.


But that wasn’t the reason for my astonishment.  From the title of the book it is clear what the subject of this 400-page collection is “Airborne contagion and Air Hygiene”. This is also explicitly stated in the subject description (page 319):

“Droplet infections are primarily airborne; airborne epidemics are absent from an ecological population provided with adequate air hygiene”.

And the whole book is about that. With regard to a whole series of diseases, which pass through infections. Especially through bacteria/parasites, but also through viruses. A large number of experiments are reported on. How the infection then goes and what measures can be taken in the indoor climate to prevent it.  Really impressive.


But I fell off my chair when it came to the animal experiments with the tuberculosis bacterium and the influenza vaccine. In both trials there were results that Wells himself says: “truly astonishing” (page 119). There was a big difference between the animals that were “offered” the big drops and the animals that were “offered” the micro drops.

The difference was a factor of 16 times. 32 of the 33 animals that inhaled the aerosols got a lung infection. None of the animals that were offered the large drops showed a form of swallowed infection after 6 weeks.

In short: larger drops do not cause an infection with tuberculosis, but it happens entirely through airborne microdroplets, which are inhaled by the animal (man) for a while and then “nestle” in the lungs.

But yes, one will object, tuberculosis is a bacterium.

But then on page 119 we see the following about experiments with mice: “Influenza virus inhaled in large and small drops DUPLICATED the effect observed in experiments with tuberculosis”. Mice that inhaled the aerosols died quickly. While the mice that had come into contact with the large droplets were much better off.

It then goes on to say that the influenza virus inhaled in microdroplets was much more contagious than if those drops had been removed from the air and inserted into the nose.

The rest of the chapter describes other tests with other infectious diseases, such as group C Streptococci. And the results are always the same.


The small particles can penetrate directly into the lungs and there, if they are in sufficient numbers, very much household. Larger particles/droplets do not succeed or to a much lesser extent, Wells states. They are retained in the upper respiratory tract and do not lead to contamination, or only to a much lesser extent.

It is astonishing that the much vaunted handbook of 1955 already explains very explicitly that the aerosols are a major danger in almost all diseases that have been studied. They go directly to the lungs and do their destructive work.

The large drops (cannonballs or not), if they hit you at all, enter the upper respiratory tract and are very difficult to reach the lungs.

But WHO, and therefore all CDC’s in the world, don’t adhere to what Wells has been experimenting with since 1955. The danger does not come from the larger drops. We have to protect ourselves from breathing in the aerosols too long. And we can abolish social distancing, keep 2 meters, 1.5 meters or 1 meter worldwide.

Fresh air and higher humidity are the protection against the aerosols staying in enclosed spaces for a long time. Outside, the aerosols don’t get stuck around you and you are completely safe.


Do you understand why there were such large outbreaks in slaughterhouses all over the world (little ventilation and low temperatures, the ideal circumstance for the virus to float)? But do you now also understand why WHO and the CDC’s don’t mention it as such, because if they acknowledged it, their whole position about social distancing would be undermined.

And what happened in Beijing lately also confirms that pattern. (In a wholesale center near the meat and fish department, where it is also much cooler than elsewhere).

Outbreaks in hot areas also seem to be related to the use of air conditioners

As long as WHO and CDCs do not maximise their efforts to prevent the floating viruses, but do want to keep the one and a half meter of society afloat, hundreds of thousands of people worldwide will die needlessly (if not more) and the economy and society will be held in a stranglehold of having to keep their distance.

I hope that politicians and media and citizens now realise that RIVM, OMT and the usual suspects in the media, are wrong and have led to the wrong policy with enormous social consequences. On the basis of this information from Wells and what we now know about superspread events, it is easy to implement a simple policy in which the risks of infection can also be kept well under control in the autumn and the economic and social consequences can be greatly reduced.