At a recent conference, the World Health Organization (WHO) declared that letting SARS-Cov-2 circulate unhindered in the hope of achieving so-called “herd immunity” is not an option.
Why do they say that?
Letting the virus circulate freely will cause a lot of deaths, but herd immunity will be achieved more quickly which will lead to our lives returning to normal. That was the strategy of the British government before it changed course. It was the strategy of Sweden, which has more deaths per million inhabitants than France and now suffers from a second wave of the epidemic. According to the WHO, this strategy is not viable, particularly for ethical and scientific reasons. In fact, according to its Director-General: “Allowing the virus to circulate without control, therefore, means allowing unnecessary infection, suffering, and death. »
Ethics and Coronavirus
The ethical principle we want to respect and maximize here is to reduce the number of negative consequences. It is difficult to measure the total number of consequences in a pandemic as there are always hidden effects. However, the circulation of such a virus could cause directly measurable damages in a very short time. More importantly, it would be beyond our control. Although the economic consequences are dramatic, they remain under the greater control of humans.
Therefore, the equation world leaders must solve is: limiting the circulation of the virus while protecting the inhabitants of each country from extreme poverty, which would lead to food shortages and an increased mortality rate. Political decisions often have unintended and sometimes catastrophic consequences if the risk-benefit ratio has not been thoroughly studied.
In a recent article, the Pasteur Institute briefly explains what herd immunity is: “Herd immunity is the percentage of a given population vaccinated/protected against an infection in which an infected subject introduced into that population transmits the pathogen to less than one person on average, effectively rendering the epidemic extinct because the pathogen finds too many protected subjects. Immunity of this group or herd can be achieved by natural infection or vaccination (if a vaccine exists).”
This requires that the natural infection or vaccine provide sufficient protection to act as a barrier against the virus. In the case of a natural infection, it is known that the immunity to classic cold coronaviruses does not last long: from a few months to a maximum of one year. Which is why one person can have several colds in the same year. As for Covid-19, we still know little about our immunity to it and its duration. For instance, what kind of immunity asymptomatic carriers develop? There are still too many unknowns to take a chance with this strategy.