Vaccines give additional protection to those who have already had COVID-19 | covid vaccine | COVID-19 | WORLD

Vaccines against COVID-19 They confer additional protection, especially against serious illness, to those who, before the puncture, had already had the SARS-CoV-2according to two studies published by The Lancet Infectious Diseases.

The first study, carried out in Brazil, indicated that four vaccines (CoronaVac; Oxford-AstraZeneca, Janssen y Pfizer-BionTech) they give additional protection against symptomatic reinfection, hospitalization and death in people who have already had COVID-19.

Another study, of an observational type and carried out in Sweden, concluded that, after three months, people who recovered from COVID-19 had a lower risk of reinfection up to 20 months later. In addition, vaccination provided additional protection to people with a previous infection for at least nine months.

Neither of the two studies included analysis of reinfection from omicron variants.

Vaccines have been shown to be highly effective in preventing symptomatic infection and hospitalization among those who had not previously had COVID-19, but it was less clear in those who had.

The lead author of the first study, julius crodafrom Federal University of Mato Grosso do Sulsaid Understanding the duration and effectiveness of immunity for those vaccinated with a previous diagnosis of COVID-19 is increasingly important as the pandemic progresses and spikes may occur due to more transmissible variants.

In the study carried out in Brazil, among people who had suffered from COVID and were later vaccinated, the effectiveness against symptomatic reinfection was 39% for CoronaVac; 56% with AstraZeneca; 44% for Janssen and 65% for Pfizer.

The effectiveness against hospitalization and death with CoronaVac was 90%; Astrazeneca (58%); Janssen and Pfizer (90%).

“There has been an ongoing public debate about the need to vaccinate previously infected people. Our results suggest that the benefits of the vaccine far outweigh any potential risk and support the case for vaccination, including the full series of vaccines, among people with a prior SARS-CoV-2 infection.”Croda said.

The Swedish study examined both long-term protection from prior infection, and the potential for additional protection generated by hybrid immunity (a combination of infection- and vaccine-driven immunity).

The results indicated that previous infection with SARS-CoV-2 reduced the risk of reinfection by 95% and hospitalization by 87% from three months to 20 months after the initial infection.

“As expected, there was a higher likelihood of hospitalization during the first three months after initial infection, highlighting that infection-driven immunity is not without risk.”highlighted Anna Nordströmone of the signatories of the study of the University of Umea.

However, those who recovered experienced 87% protection against COVID-19 during the rest of the follow-up, which remained high up to 20 months.

Hybrid immunity (two doses of vaccine and having had the disease before) reduced the risk of infection by 66% in the first two months and by 56% in the nine months of follow-up.

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