Since the beginning of the pandemic, some people have never been infected despite their exposure to risk. Genetic mutations, past encounters with other viruses, blood type, lifestyles…: researchers are trying to unravel the mysteries of this natural shield.
Why, since the start of the pandemic, have some people stubbornly resisted infection with SARS-CoV-2 while so many others, faced with the same risk situations, were quickly infected? The question fascinates as much as it intrigues. The enigma, however, appears as tough as the subjects to which it devotes itself. Genetic mutations, past encounters with other viruses, blood type, lifestyles…: many are the avenues explored. Already, some are taking shape with greater clarity.
Who are these resistant to the virus? “The typical example is that of close intra-family exposures. In a couple, for example, one of the two partners can be affected without always knowing it: it happens that his spouse remains unscathed,” says Professor Laurent Abel, co-director of the laboratory of human genetics of infectious diseases at the Imagine Institute ( Inserm, Necker Hospital, Paris). Not to mention those who, despite a risky profession, have always passed between virus-laden drops, droplets and aerosols, even when masks were not available.
We still have to agree on this natural protection. There are people who resist infection with SARS-CoV-2 despite obvious exposure to risk and in the absence of vaccination. And then there are those who are infected but do not develop serious forms of Covid-19. These two categories of resistance, a priori, are due to different shields. Only the first concerns us here.