“With current knowledge, the anti-Covid vaccine should not be given to those who have had the disease “. Nino Mazzone, director of the Medical Area, Chronicity and Continuity of Care Department of the Asst Ovest Milanese, who in November 2020 found himself hospitalized for Sars-CoV-2 infection in the department he directs, had told Adnkronos Health at the beginning of December. A battle carried on with the patience and perseverance of the internist – “the ‘median’ of medicine”, is the football metaphor he loves to use to describe his profession – now supported by the evidence of the numbers: “The probability of reinfection for a recovered from Covid-19 is 0.07% at one year. Better than the vaccine “, says the head physician of the Civil Hospital of Legnano, in the Milanese area, creator and coordinator of a work published today in ‘Jama Internal Medicine’.
“After a year – reports Mazzone, summarizing the key data of the cohort study conducted in an area of Lombardy among those with the highest health burden – on over 122,007 swabs, of which 15,960 positive with 1,579 hospitalized patients, just 5 former patients they are reinfected and none of them have developed a clinically important pathology. Only one ended up in hospital and 4 were people who, for work reasons, attended healthcare environments, therefore more at risk of contagion “.
Five ‘return’ cases out of almost 16,000 positives, therefore. “A figure that,” adjusted for age, sex, ethnicity and health area – specifies the specialist, who signed a ‘Research Letter’ together with his group in the journal of the American Medical Association – translates precisely into a risk of reinfection of 0 07%. The mean interval between primary infection and reinfection was over 230 days. ”More than 7 months.
“Of the 13,496 people in the” cohort “who were not initially infected with Sars-CoV-2, 528 subsequently developed a primary infection. The incidence per 100,000 population is equal to 1 for reinfections, compared to 15.1 for new infections “, adds Mazzone.
“The observation ended when the variants of the pandemic coronavirus began to spread in our territory, therefore we cannot estimate the influence of this variable on the final results”, specify the authors of the research, including the president of the Italian Clinical Microbiologists Association (Amcli), Pierangelo Clerici.
However, “these results of ours confirm that reinfections are very rare events”, they point out. “Our study – they conclude – suggests that the natural natural immunity to Sars-CoV-2 could confer a protective effect for at least a year, a figure similar to that which is close to the protection reported in recent studies on anti-Covid vaccines”.