In Catalonia, scientists claim to have detected a case of reinfection as little as 20 days between two infections. Researchers question the immunity conferred by an initial infection and by vaccination.
This is a phenomenon that scientists are watching with great concern: that of reinfections COVID-19† At a time when the BA.2 variant, which is highly contagious, is responsible for 96% of infections, researchers are questioning the protection offered by infection with the virus and by vaccination. What raises questions is the case of a 31-year-old woman who was re-infected with the virus in Spain just 20 days after an initial infection. This is the shortest time between two infections since the start of the pandemic.
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This medical case, which will be presented at the European Congress of Clinical Microbiology and Infectious Diseases in Portugal at the end of April, was discovered last December. The young woman was first infected with the Delta variant and three weeks later by the Omicron variant† This medical case is all the more surprising as the 30-year-old presented a full vaccination schedule: This Spaniard had received her booster vaccination for 12 days before testing positive for the virus in December 2021 thanks to her job’s routine swab program. The young woman placed herself in solitary confinement for 10 days before returning to work in January and becoming infected again.
What protection?
“This case highlights Omicron’s potential to escape previous immunity acquired, either through natural infection by other variants or through vaccines, describes Dr. Gemma Recio of the Catala Institute. In other words, we can no longer say that a a person already infected with Covid-19 is fully protected against re-infection with the virus, even if he has completed his vaccination schedule.
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dr. However, Gemma Recio says that a previous infection or vaccination against the virus “seems to protect in part” against the development of severe forms of the disease, especially in “people infected with Omicron”. For the Catalan scientist, this shows that in the coming months it will be necessary to maintain “genomic surveillance of viruses in fully vaccinated people prone to reinfection”.
Weakening of the immune response
In France, cases of reinfection are not uncommon. In France, a study published last March by Santé Publique France had identified 685,858 possible cases of reinfection between March 2, 2021 and March 20, 2022. Re-infection cases are defined as all people who presented at least two positive tests registered in the database and performed at 60 interval days or more. The time between the two infections was an average of 242 days, according to the authorities.
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“It seems likely that the attenuation of the post-infectious or post-vaccination immune response in the French population plays a role in this marked increase in the frequency of possible re-infection cases, particularly in people who have not received a booster dose of the vaccine. Public Health France at the time. It is also very likely that the very strong distribution in France of the Omicron variant, characterized by increased transmissibility and significant immune escape, amplifies this phenomenon.”
