We have probably come close to the maximum number of infections that can be detected in a day. • To avoid locksmithing, the activities in which most infections occur should be limited.

The corona taught us an important lesson in modesty. We have learned that it is difficult to predict and certainly not worth announcing too early that we have won. Therefore, instead of predicting, I will concentrate on the picture that emerges from the data as of today, while understanding that what will actually happen depends largely on the actions taken and perhaps even more on the actions not done. A good understanding of the current situation is of course critical in deciding on the next steps.

Corona testing complex in the Neve Sha'anan neighborhood of Tel Aviv // Archive photo: Shmuel Buharis

From the data of recent days it is possible to reach two opposite conclusions about our situation. On the one hand, the number of infected is relatively stable around 1500, and the doubling rate of the number of infected has already increased from one to two weeks. That is, there is no exponential growth, certainly not rapid, and ostensibly we are in the process of halting the spread of the virus.

is it possible? That without any change, without comprehensive epidemiological investigations, without increasing the number of tests, and without enough time to see the effect of the last line of restrictions, we got lucky and the spread stopped? It's hard to believe, but we've already said that it's worth focusing on data and less on explanations and beliefs.

And here we come to the other side of the data, the ones that lead to the opposite conclusion. Number of serious patients. It is growing, in an exponential growth that currently doubles itself every 6 days. In the last two weeks, about 300 new critically ill patients have been added, and at the current rate in the next two weeks, more than 1,000 critically ill patients will be added. The outlook for the future is even gloomier. It is reminiscent of the horror scenario we were warned about in the first wave, the one that could endanger us in the collapse of the health care system in the coming weeks. 

How do you reconcile the contradiction in these opposite conclusions? There is a simple explanation, which unfortunately points to the continued spread of the virus. Apparently we have reached close to the threshold of the maximum number of infections that can be detected with about 25,000 tests per day. As you approach the threshold, the number of infections that will be detected each day will indeed show stability. But in practice, the epidemic continues to spread, which will be reflected in an increase in the severely ill, just as is happening these days.

Another prediction of this scenario is that the percentage of severely ill patients is expected to rise, and this phenomenon has also begun to occur. If this is indeed the reality, then the actual number of infected already stands today at many thousands, and is even expected to increase. Such an amount of infections cannot be contained with the amount of tests we have. Even an effective investigative body of infected people, which we do not have anyway, cannot cover such an amount of infected people. too late.

Why is the daily infection threshold that can be detected so low? First, because most close contacts with a verified patient end without infection. Therefore, since the testing policy has been extended to include testing for asymptomatic people who have been in the vicinity of a verified patient, such as the classmates of an infected child, for most of them the test result will be negative.

Second, because even if they only tested people with symptoms, most of them came out negative. This is because corona symptoms are not unique to corona and are common with other diseases. That is, the threshold is low because it is difficult to find a testing policy where the percentage of positive tests will be above 5-10%, which currently allows about 2000 infections to be detected per day. Indeed, the percentage of positive tests has remained relatively stable recently at about 5% and even in the first wave it reached only 8% at its peak.

Still, a little optimism and a few words about what can be done. Our corona questionnaires on the site continue to indicate an increase in the use of masks and an increase in social distance at all ages, and it is possible that the inhibition of adhesives is real and results from it. Also, the definition of who is a seriously ill patient has recently been expanded and it is possible that part of the increase in the seriously ill is due to this change.

What can still be done to avoid a general locksmith? The answer is clear. The same activities in which most infections occur should be restricted. The problem is that this information does not exist, but it can be obtained quickly, using a simple idea that can be started tomorrow.

For anyone sent for examination because of contact with a verified patient, HMOs should document the nature of the place (synagogue, restaurant, pool, gym, etc.) where the contact occurred. Within a few days, information should be accumulated about 100,000 contacts, which will make it possible to obtain a lot of data about the risk centers, and the percentage of contacts in any activity that ends in infection.

The benefit of this knowledge is twofold. It will allow to restrict only those activities that cause infection and thus reduce the spread and need for general closure. We can also better prioritize contacts for which it is worth sending people for testing and isolation. Although the train has left, the destination we will reach still depends for the most part on us.

The author is a scientist at the Weizmann Institute of Science