A vast American study published Thursday in “Nature Medicine” shows that a reinfection by the Sars-Cov-2 doubles the risks of death and triple those of hospitalization and cardiac problems.
By Delphine ROUCAUTE
The extreme contagiousness of the omicron variant appeared at the end of 2021 made cases of reinfections very common. But are they nevertheless mild? This is the question to which the team of Ziyad al-Aly, at the health center of veterans of Saint-Louis, in Missouri, tried to answer in A study published in the journal Nature Medicine Thursday November 10 . And for the epidemiologist, the answer is clear: “Reinfection is not benign, it is better to avoid it.”
Main interest in their work, this study was conducted on the very large national health care database of the American Ministry of Veterans with nearly 5.8 million people, including more than 443,000 people who been infected at least once by the COVVI-19 and nearly 41,000 having been reinfected between the 1 er March 2020 and April 6, 2022. Their results show that the reinfection by the SARS-COV- 2 has doubled the risk of death and tripled those of hospitalization and heart problems. There are many sequelae identified, in particular pulmonary, cardiovascular, hematological, diabetic, gastrointestinal, renal, mental, musculoskeletal and neurological disorders.
The risks are increasing with the number of infections
These risks have been observed in vaccinated individuals as well as in non -vacinated, more pronounced at the time of infection, but up to six months later. “Even if a person has had a previous infection and has been vaccinated -that is to say that they have benefited from double immunity, that of previous infection and that of vaccines -, it is always likely to undergo undesirable effects in case of reinfection “, insists Ziyad al-Aly . In addition, the risks increase with the number of infections.
The severity of reinfections depends on diseases. Some provide persistent immunity over time, such as measles or chickenpox. Others make it possible to acquire immunity that decreases over time; The impact of the virus will then depend on the state of health of the person or the new strains in circulation, as is the case with the flu, whose sanitary burden varies from one year to the next. Only dengue reverse logic: a past infection can worsen the consequences of a second meeting with the virus.
The results of the American team do not mean that people contaminated several times by the COVID-19 are more seriously sick during their reinfections than their first meeting with the virus. Studies have also shown the opposite. That led by Méreh J. Abu-Raddad and published in July in New England Journal of Medicine emphasizes that people vaccinated in two doses and already contaminated once have, depending on the type of vaccine, 94 % to 100 % less risk of contracting a serious, critical infection or fatal. A priori, contaminated and then vaccinated people are therefore the best protected against the risk of serious form.
You have 37.13% of this article to read. The continuation is reserved for subscribers.