Covid: reinfection cases increased markedly since the Omicron variant broke out

Published by Graziella L. · Published on 4 April 2022 at 13h00
With the Delta variant, it was much rarer to be reinfected by Covid-19. But since the Omicron and BA.2 variants broke out, it is different, since reinfection cases have increased markedly since December 2021.

Covid-19 seems to have a lot of surprises in store since from one variant to the other, symptoms, transmissibility and reinfection toll utterly change. As a matter of fact, with the Delta variant, as soon as one was contaminated, it was rarer to be infected again. The outbreak of the Omicron variant yet was a game-changer with markedly increasing reinfections.

This assessment can be easily made around you. Right amid a contamination peak since mid-March, France sees the Covid-19 sick toll increase, and yet without any incidence on the hospitalization toll. Many French people have been contaminated with Omicron in January, and test positive again this April. Some have even been infected 3, 4 or 5 times by the same variant.

In all, 685,858 cases of likely reinfection have been reported in one year, between March 2, 2021, and March 20, 2022. 95.2% of these cases yet happened since December 6, 2021, namely the start of the Omicron variant spread in France. And this could be underestimated since not all the French are tested when showing Covid-19 symptoms.

Reinfection is estimated when the time period between two positive tests is beyond 60 days. According to Santé Publique France, the time between two infections is an average of 242 days. This increase in the rate of reinfections could happen because of a milder immune response after an infection or vaccine too old. But the arrival of the BA.2 sub-variant – dominating since late February – could also have an influence since with it, reinfection can happen less than 60 days after the first infection.

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