Summary of the article
An explanation of why a wave did arise during this summer, despite the better situation regarding ventilation and humidity. But the effects of this wave appear to be more favorable in both the short and longer term.
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Read full article: Why a wave in the summer?
Reading time: 5 minutes
It’s summer isn’t it!?
I get the – justified – question from various sides: how is it possible that many people become infected, while it is now summer? The pattern of spreading the virus would resemble that of the flu and we have it in the fall and winter after all! In summer the humidity is still high and there is much more natural ventilation (with windows and doors open).
In the answer I’m giving now, I won’t go into too much detail about exactly how the infection progressed and progressed with the different mutations of the virus.
It is known that Omikron is much more contagious, but also much less virulent than the first variant. Partly because of this, there are so few patients in intensive care, while the sewage water figures are now higher than at the end of November 2021. But then there were 15 times as many patients WITH or BY Corona in the ICUs.
Just look at this graph with the development of the sewage figures and the occupancy in the ICs.
It is easy to see how with the emergence of Omikron in January 2022, the IC occupancy followed a completely different pattern than before. If the sewage figures indicate the real development in the number of infected people in the Netherlands, then at the end of March 2022 we will see that there are 2.2 times as many virus particles in the sewage than at the peak at the end of 2021. But the IC occupancy is a factor of 5 times so low. This means that at the end of March there will be a factor 11 times less IC occupancy compared to infected people than in December 2021.
At the moment, the number of virus particles is a factor 1.5 times higher than at the peak at the end of 2021. But the IC occupancy is now a factor 14 times lower. That would now result in a factor 21 times less IC occupancy than in December 2021. (This lower occupancy can partly be due to shorter lay times)
How do you get infected?
A person becomes infected when so many virus particles enter that multiply, without the body being able to stop that multiplication sufficiently, so that an infection occurs. That infection means that you could get certain complaints and that you also have the chance that you spread virus particles, which in turn enter others.
As regular readers know, I have been assuming for more than two years that the spread of the virus is almost entirely through the air. The virus is released from the respiratory organs of one person and mainly inhaled by the other. The virus can then settle in many places. It seems that the current mutation does that much more in the upper respiratory tract, whereas before it happened more often deep in the lungs.
Two components are then decisive:
- How many virus particles do you ingest in a certain period of time?
- What protective equipment does your body have to ensure that the virus particles that have entered do not multiply quickly?
1. Virus particles inside
That number is determined by the number of complete virus particles that are in the air you breathe. And that again depends on what part of the air you’re breathing comes from another person spreading virus particles.
You never know if someone is there spreading virus particles. The more the virus reigns and the more people you are in a room, the more virus particles will hang in the air.
The number of virus particles can be significantly reduced through intensive ventilation, the right humidity and air filtering. However, it will not be completely zero. Even outside it doesn’t have to be that way. But you do know that the number of virus particles will then be so low that the risk of being infected by them is very small.
It is also the case, and that is the core of human development from baby, that our immune system is trained precisely by coming into contact with virus particles and bacteria. So limited contact with it is usually beneficial.
2. Protection of the body
Our human body is built to deal with viruses and bacteria in a good way. Sometimes it makes us sick, but at the same time, you are much less likely to get sick next time, and even less likely to get very sick next time.
That training takes place in the first years of your life. (I well remember having chickenpox, measles and mumps in the early years). When you get a lot older, that degree of protection of your body decreases again.
The strength and attitude of your immune system can differ from person to person. It depends on many things, which makes you strengthen or weaken your immune system.
In addition, there are also vaccinations and medicines that reduce the chance that the infection will develop and/or lead to major consequences. Sometimes very effective, but sometimes the effects are minor.
So it’s the combination of 1 and 2 that determines whether you get infected or not!
What is different now than in March 2020?
In March 2020, the then prevalent variant of the virus had a reproductive factor of 2.5. In addition, there were few people who had an immune system that could stop this virus, as it were. People became infected if the viral doses were exceeded.
Measles has a reproductive factor between 12 and 20 (and is completely airborne, as it has been recognized since 1985). Yet few adults get measles because their immune systems have learned to fight measles. So, despite that very high reproductive rate, we’re not seeing any major measles outbreaks.
The current mutation of Omikron (and certainly the most recent BA. 5) has the same reproduction factor as measles, so around 15. And is already a lot higher than that of the original Omikron mutation.
It is crucial to realize what causes the difference in reproduction factor. For this article, it is sufficient to assume that this is because fewer virus particles are needed to infect someone. (That process is complex. But on balance, the effect comes down to the fact that, if your immune system has no protection against the virus, you will sooner cross the limit in this variant at which the virus can multiply quickly within your body.)
So the viral dose needed to get infected is then – a lot – lower. In this article I will discuss this topic in detail.
And that’s why a new wave
A combination of two factors now ensures that there is a new wave of infections:
- The viral doses to become infected are a lot lower than in 2020
- Immunity protection of the population against the latest Omikron mutation has decreased. It doesn’t matter at the moment which factors are responsible for this.
Good ventilation, higher humidity and air filtering do ensure that the number of viruses in the air decreases. But due to the lower viral dose threshold, this is increasingly difficult to achieve, even in the summer.
However, the question is even whether you should also put in your maximum effort now? There are also several arguments against this:
- There are so many places where you can come into contact with the virus that protection in one location will not significantly lower your overall risk.
- If you come into contact with the virus now, you will build up better protection towards the winter.
- The current variant usually hardly makes you sick.
- It is better to get a disease of the respiratory organs in the summer than in the winter.
Fortunately, there is currently no hysteria about this wave in the Netherlands. There are some places in the world where people do fall back on measures.
More and more people are realizing that this virus is not as dangerous or more than they thought. And also feel stronger and safer.
It remains to be seen what will happen in the fall. Is there a more virulent variant emerging? Can we be scared again about a new variant? Whether the hospitals are again overrun by patients, whether or not by this virus or another (think of influenza).
We spend more and more time in enclosed spaces, especially in autumn and winter. And then it is certainly advisable to ensure that you inhale little air that others have exhaled. Whatever infectious disease it is, it reduces your risks for it.
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