Among those recovered from Covid-19, vaccinated people have a more than halved risk of getting infected again compared to unvaccinated people or to catch Covid again with severe symptoms. This is demonstrated by a meta-analysis, signed in ‘Frontiers in Medicine’ by a group of Italian researchers, coordinated by the epidemiologist Lamberto Manzoli, director of the School of Hygiene and Public Health of the University of Bologna. The authors examined 18 studies conducted in different countries of the world on a total of 18 million people.
“Our results confirm that, among the healed” from Covid, “those who have received two or three doses of vaccine has a 50-60% lower risk of reinfection than those who are not vaccinated – explains Manzoli -. Considering that the number of people recovered” from a Sars-CoV-2 infection “amounts today to hundreds of millions all over the world, these data appear particularly encouraging and provide strategic information for future pandemic control policies”.
The research team also involved scholars from the University of Ferrara and the Sapienza University of Rome, and evaluated various aspects of the Covid-19 reinfection, including any differences between vaccinated with two and three doses, the persistence of protection 12 months after latest infection and the severity and contagiousness of the different variants. Two main findings emerged, the scientists report. First: “Vaccination halves the probability of reinfections compared to natural immunity alone obtained with a recovery from the virus”. Second: “Even if a second infection occurs, the likelihood of developing severe symptoms is halved in vaccinated people. Similar levels of protection have been observed in people vaccinated with a single dose, even for the Omicron variant, and up to 12 months after ‘last infection’.
Manzoli is keen to underline that “the vaccines have reduced a fortunately already low risk. In absolute terms, the number of reinfections may seem worrying, but the cases of severe or fatal symptoms of Covid-19 among people who have already recovered once are relatively infrequent: less than 1 in 1,000”, points out the epidemiologist.
“These results – he concludes – can therefore be useful for planning specific immunization strategies for people who have contracted the coronavirus” Sars-CoV-2.
#Covid #vaccine #risk #reinfection #halved
