We are as well protected against Covid when we have been previously infected with the virus as if we have been vaccinated, concludes Friday one of the largest studies on this crucial subject for the management of the epidemic. “Even if an infection gives a protection which decreases over time, the level of this one (…) seems as durable, even more than that conferred by vaccination”, concludes this work published in the journal The Lancet.
This comparison is based on the messenger RNA vaccines from Pfizer/BioNTech and Moderna, which are among the most effective against Covid and are the spearheads of vaccination campaigns in many Western countries. The subject is not new and many studies have already tried to compare the risks of catching Covid again, depending on whether you are vaccinated or have already been infected.
But the work published in the Lancet is of an unprecedented scale: it compiles around sixty pre-existing studies, with a decline of several years which notably takes into account the emergence at the end of 2021 of the Omicron variant. The latter proved to be much more contagious than its predecessors and capable of infecting many vaccinated people, without them running a high risk of a serious form.
Towards a “hybrid” immunity against the virus
The Lancet study concludes that the same applies in the event of past infection with the coronavirus: the protection is rather weak against reinfection with Omicron, but solid against a severe form. These results do not mean that it is indifferent to be vaccinated or to be infected to acquire a first immunity: it is indeed much more risky to fall ill, in particular at the oldest.
However, this study gives a more accurate picture of what can be expected in the population from the development of “hybrid” immunity, as more and more individuals have been both vaccinated and sick at least once. “In the long term, most infections will strike people who are well protected against severe forms, following a previous infection, vaccination or both”, underlined researchers, not involved in the study, in a commentary also published by the Lancet.
These results therefore raise hopes that future waves of Covid will result in low levels of hospitalizations, they conclude.