In 2022, France will experience more waves of covid-19 than seasons. The fifth came at the end of November. Yet another viral comeback since the start of the pandemic which will increase the counter of infections per individual. Displaying three or four will soon no longer be rare…
Probability of death doubled
What risks, in terms of health complications, can these multiple encounters with SARS-CoV-2 generate? A large study, carried out in the United States, on a cohort of veterans, and published this month in the journal Nature Medicine, tried to provide an answer. In the established group, more than 440,000 individuals had contracted covid-19 between March 2020 and April 2022, and nearly 10% had two or more infections. By comparing with an uninfected control group, scientists at Washington University in St. Louis, Missouri, were able to establish that reinfection led to a doubled risk of death and threefold hospitalization, as well as an increased likelihood of suffering sequelae, including pulmonary, cardiovascular and neurological. “The risks were more pronounced in the acute phase of the disease but persisted in the post-acute phase at six months”, describe the authors of the study.
“Risk is cumulative”
Contacted, several French scientists consider the study “interesting” and built “on a very well-known database” even if they point out some limits such as the constitution of the sample, not representative of the population because it is older and essentially male, notably. “These results are not very surprising even if it is necessary that other research come to invalidate or confirm them”, comments Mahmoud Zureik, professor of public health at the University of Versailles Saint-Quentin-en-Yvelines. “A lot of work has already shown that once you contract covid, serious complications, essentially cardiovascular or neurological, can occur in the month or months that follow, in proportions that remain low, not to mention covid. long. However, when you accumulate infections, you accumulate these low probabilities of complications”, analyzes the scientist, also director of EPI-PHARE, public structure of expertise in epidemiology. “The risk is cumulative, when you play the dice several times, you end up having more chances of making a double-six”, abounds Pierre Tattevin, head of the infectiology department at the Rennes University Hospital.
This increased risk could also be caused by several physiological parameters such as “a long-term inflammatory state” and “stimulation of the immune system”, suggests Olivier Schwartz, head of the virus and immunity unit at the Institut Pasteur. The virologist also considers it “interesting” that the increased risk of complication is highlighted, regardless of the vaccination status of the people in the cohort.
“A real public health problem”
Today, the Omicron variant is considered less severe than the previous ones. Can we hope for fewer health concerns after several “omicronian” infections? “Repetition undoubtedly increases the risk of having problems. By dint of covid, we are more and more shaken, but since the viruses are less and less virulent, the general trend is that the second or third covid are less aggressive than the first, “considers Pierre Tattevin, also vice -president of the Society of Infectious Pathology in the French language (Spilf). However, the phenomenon is not to be taken lightly, concludes Mahmoud Zureik: “By dint of letting the virus circulate, we will be infected, re-infected, re-re-infected, and the low risks of complications will be added until they become a real public health problem, at some point”.
letelegramme Fr Trans