Several periods of social distancing will no doubt be necessary until 2022 to prevent the new coronavirus from clogging up sick hospitals in the United States, Harvard researchers believe in a study published Tuesday by the journal Science. The Harvard team modeled the pandemic Covid-19, the disease caused by the virus, on the assumption that it would be seasonal like other viruses of the same family, including coronaviruses responsible for colds, who love winter.
Their simulation had to accommodate many unknowns on the newcomer, baptized SARS-CoV-2, in particular on the level and the duration of the immunity acquired by a contaminated person. “An ad hoc measure of social distancing will probably be insufficient for the incidence of SARS-CoV-2 to remain within the limits of the capacity of resuscitation services in the United States”summed up one of the authors, Stephen Kissler, in a conference call Tuesday with journalists.
“In the absence of treatment, intermittent periods of social distancing will no doubt be necessary”, he said. The duration and degree of containment may be reduced when effective treatments or a vaccine are discovered. Until then, it will be necessary to oscillate between confinement and opening in order to prevent a new wave and allow the health systems to deflate their resuscitation services.
Marc Lipsitch, professor of epidemiology, explains that by accepting periods of higher contamination, during episodic deconfinements, the virus will inevitably contaminate an increasing proportion of the population (ideally, the youngest and less vulnerable, who are less likely to ‘die). This will make more people sick, but will have the advantage of gradually building the collective immunity of the population, i.e. the level at which there will no longer be enough people likely to be infected for as the virus continues to circulate.
Too much confinement, on the contrary, would prevent this collective immunity from being built, simulated the researchers, who conclude that the most effective approach is the intermittent maintenance of measures of social distancing (confinement, closure of schools and businesses. .). It is not yet known whether infected people will develop short or long-term immunity. For cousin viruses, such as colds, immunity erodes after a year. For Sras, it is long.
One thing is almost certain, according to the study’s authors: the new coronavirus is not going to disappear overnight. According to them, it is improbable that the immunity is strong enough and durable enough for the coronavirus to disappear at the end of the first wave that we are crossing at the moment (unlike the SARS of 2002-2003).
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