While the Cabinet announced this week that measures for schools, catering establishments and the elderly are being relaxed, the RIVM modellers are busy calculating the consequences.
The number of new infections can still be predicted in the coming weeks. But the forecasts for the summer are very uncertain. One thing is clear: testing and detecting new infections will be crucial.
“Hospital admissions are likely to increase, and if you don’t want that to happen, it has to be all in order,” said Jacco Wallinga, RIVM’s chief modeller.
The NOS spoke to him about whether the number of infections can decrease even further – and how realistic it is that people infect each other outside.
It was busy in many places on Ascension Day. Is that something of concern to you?
“Busy in itself is not really a problem, but if that leads to people getting much closer together, it can lead to more infections. It is difficult to measure that exactly. The other side of the story is that the chance of to be infected now is very low, compared to the peak in mid-March. It is not that we are worried, but we are not sure yet how it will turn out. “
Wallinga points to studies from Europe and Japan showing that few outbreaks have occurred outdoors. “I myself would estimate, based on what we know from the literature, that the risk outside is considerably lower than inside,” he concludes. But he does not know a good study in which the risk of contamination indoors and outdoors is compared.
Pass each other in a forest or shopping street less than a meter. How likely is it that this will lead to an infection?
“The basic rule is that a meter and a half is safe. I can’t put a number on it. It’s better to keep your distance than stand next to someone. And it’s better outside than inside. But then there are things everyone can come up with, not things we calculate. “
This week, the cabinet announced that the planned easing of the measures could continue after 1 June. Cafés, restaurants, museums, secondary schools and cinemas are all allowed to open again under certain conditions. Older people over 70 may also receive visitors again.
Jaap van Dissel showed various scenarios in the House of Representatives that you had calculated. This shows that the total package of relaxations in the autumn is likely to lead to a second wave. Is that right?
“The main picture is that it is all very uncertain. The most plausible is that the number of hospital admissions is increasing, but very slowly.”
“That uncertainty is because we have to stack uncertainties on each other. First, how effective was the measure that is now being relaxed? Then we cannot estimate exactly, because many measures were taken at the same time. The second is: how effective is the source- “We didn’t include that here, so if they’re as effective as planned, we won’t even see the increase in hospital admissions. Besides, are people going to follow the basic rules in August and September?”
But if the source and contact research is not going to work well, then the most likely scenario is that there will be a second wave in October?
“Without source and contact tracing that would lead to a second wave, but the source and contact research will really come. The question is: will it be effective enough to neutralize this wave? If the source and contact research does not work And our models turn out to be right, you would see a wave. “
Wave? Once the line in the graph goes up, it keeps going up.
“Only if you do nothing. But in the presentation, Jaap van Dissel also showed that you need to intervene. And the faster you intervene, the faster the situation can be brought under control again. If it increases the number of hospital admissions, then you will to reverse that relaxation. “
A new lockdown?
“No. If it doesn’t work, the numbers will increase. Then you will see that regionally and then measures can be taken. But that is not a lockdown yet. The whole system has been designed to prevent that.”
If the goal is to extinguish the virus, what is the right time to relax?
“The goal is not to extinguish the virus. You should never relax and stick to everything. A policy goal is to be able to continue to provide good care. So you don’t want the number of IC admissions goes far beyond capacity. And then you can calculate back the maximum that you can handle. “
“Then you see that you need quite a low number of IC admissions per day. You need time to realize that something is going on and then you step on the brakes. But before all infected people in intensive care you have already gone a long way. It takes a while before it comes to a standstill. “
But the longer we wait, the lower the number of new IC recordings, the more time we have to step back on the brakes if things go wrong.
“I do not know. Until now, the number of cases has been decreasing. But it may also be that an infection is showing up again, and the decrease is also less rapid. And you can see that in Germany, for example. speed decreases somewhat. At some point it stabilizes somewhat. “
Are we now at that lower limit in the Netherlands? Or can the virus go even further?
“The number is still decreasing. But I wonder: how much further is it going, and is it going down at the same rate? Time will tell.”
“Look at China, where they’re really trying to get the virus to die out. It’s a very big country, so they can afford to close the border. But they too have a hard time getting it done So you can reason how difficult it would be in the Netherlands. “
Will the summer, the nice weather, help to further extinguish the virus?
“There is not much more clarity about that. I think nobody will be surprised if it helps a little, but I also think that nobody will be surprised if it is so little that you can hardly measure it. And that is based on from what we know about other coronaviruses. “
“We calculate as if the effect in summer is just as great as in winter, and vice versa. What we calculate now is therefore perhaps a bit too pessimistic. On the other hand: if it all seems to be better after the easings in the summer , don’t count yourself rich too early. It can be quite disappointing when winter sets in. “