Cases of reinfection with Covid-19 are “not rare” in France, particularly in the context of the outbreak of contamination linked to the Omicron variant. This is what Public Health France explained, this Friday, with supporting figures
Initial work, on samples taken between January 1, 2021 and January 27, 2022, showed 416,995 possible cases of reinfection for people with two positive tests at least 60 days apart. This represents 2.8% of confirmed cases during the period studied.
We speak of reinfection when a first episode of Covid is followed by a second, with two different strains of the virus, explained the health agency during a press briefing.
Two categories were more affected: young adults, aged 18 to 40, and health professionals, possibly reflecting greater exposure to risk or less adoption of preventive measures.
Omicron responsible in 79% of cases
“A very large majority of the possible cases of reinfection reported occurred during the fifth wave of Covid-19”, observed SPF, which has counted 384,375 since the beginning of December 2021.
And the highly contagious Omicron variant appears to be involved in 79% of all possible cases of reinfection, according to available and interpretable screening results.
Similar phenomena abroad
As hypotheses to explain the increase in reinfections, the agency put forward “the attenuation of the post-infectious or post-vaccination immune response that occurred over time and the impact of the Omicron variant in terms of increased transmissibility and escape immune”.
On the rise in reinfections, the first observations in France are “consistent with what we know of reinfections elsewhere in the world”, specified SPF. This is thus the case with the data from the English, which are “rather at 10% of possible cases in recent weeks” but take into account a longer period, of at least 90 days, between two contaminations.
Santé Publique France, which has pointed out a series of limits for its first data on possible reinfections, will conduct additional studies. “These data will be crucial in order to be able to project what awaits us with this epidemic in the months and years to come,” said the health agency.