The Right Approach to Getting out of the Current Crisis

Duration of Immunity
The first misconception is based on media reports a few months ago, which claimed that dozens of people in South Korea were re-infected. The four Israeli experts say that on close examinations, these stories were wrong, and that the “re-infection” cases were nothing more than errors in testing and reporting. They say that the fact that so far not a single case of re-infection has been found means that the naturally induced immunity is good for at least eight months (the time elapsing since the first reports of the disease). The experts say that there is no reason to believe that the immunity to COVID-19 would be shorter than infection-generated immunity to other viruses, meaning that this immunity will probably be effective for years.

Herd Immunity Requirements
The second misconception, that at least 60 percent of the people must be infected in order for herd immunity to take hold, is based on two wrong assumptions. The first is that all members of society have the same level of exposure to other members of the society; the second is that COVID-19 is so new and unique that no one has any immunity to it, and that exposure to it means infection by it.

But different members of society have different levels of contacts with other people and, hence, different degrees of exposure. A cab driver and a cashier at a supermarket, for example, have contacts with many more people daily than a retired person at a nursing home or a farmer. It is precisely the people with more contacts – cab drivers, supermarket cashiers, etc. — who tend to get infected sooner, and since their infection makes them immune, they stop infecting others.

In other words, 1,000 cashiers and cab drivers who get infected, and then become immune, contribute much more toward herd immunity than 1,000 nursing home residents and farmers. Because individuals who contribute more toward herd immunity get infected sooner – and stope infecting others sooner — the virus’s spread slows down and them stops at far lower levels of infection overall.

But another fact making it possible to achieve herd immunity at a far lower levels of infection is this: Many people have immunity to the COVID-19 without having been infected with it because they had developed immunity to COVID-19 by being exposed earlier to one of the virus’s relatives. Scientists recently published an article in Cell showing that about 60 percent of Californians who have never been exposed to COVID-19, carry immunity memory cells which identify the COVID-19 and can probably offer immunity from it.

The four experts argue that the spread of the virus began about eight months ago, and that most countries have already experienced peak infection. In all these countries, the infection rate has been well below 20 percent – and this is regardless of whether or not measures such as social distancing, isolation, local lockdowns, general lockdowns, or requiring facemasks have been enacted and followed, and the degree to which these measures have been followed.

Moreover, in all these countries – and, again, regardless of the breadth and reach of, and compliance with, various measures taken to slow the spread of the virus – the rate of survival among those infected is higher than 99.9 percent.

The experts, discussing the situation in Israel, write:

If we assume that nearly 80 percent of the country’s population has cell immunity – either because of exposure to the virus’s relatives or because of other genetic reasons – and taking into account the explanations outlined above, we estimate that the decline of the epidemic will occur when we reach between only 5 percent and 15 percent of infection in the population.

This means that it would be safe to remove most of the restrictions on economic activity, and safe immediately to return to normal life by the population which is not at risk, while providing assistance to the vulnerable populations (complete isolation of nursing homes; allowing older teachers, and those with certain preconditions, not to return to teaching, etc.).

Better Approach
This brings us to the third misconception: That fewer people will die if we impose strict economic lockdowns relative to those who would die if we choose a more relaxed approach. But lockdowns only slow down infections, and infections will come back when restrictions are eased. Infections will continue until between 5 percent and 15 percent of the population has been infected, and the four experts argue that it would be better to reach that threshold sooner rather than later (while keeping an eye on the capacity of the health system to cope with a temporarily increase in the number of infected individuals who require hospitalization). Because it is impossible to keep the vulnerable communities hermetically sealed forever, the slowing down of the initial spread of the infection would, paradoxically, kill more people in the long run, as members of the vulnerable communities emerge into a population which has not yet reached the herd immunity threshold.

This brings the writers back to Sweden. In all countries, the reopening of the economy has been accompanied by a resurgence of infection, but not in Sweden. Since Sweden had no lockdown, there is no second wave of infection in Sweden.