New studies show importance of the vaccine even for those who had Covid

Two studies published this Friday (1st) in the journal The Lancet Infectious Diseases provide answers to a question that has been mobilizing scientists for months: which offers the greatest protection, the Covid infection or the vaccine?

The new research points to the importance of vaccination, even after a Covid-19 infection. Both emphasize that immunization reinforces acquired protection.

The first work is based on data from more than 200,000 Brazilian patients infected with Covid-19. Of this sample, a part of the individuals was not vaccinated. The other group was immunized with vaccines from Pfizer/BioNTech, AstraZeneca, Coronavac or Janssen.

“These four vaccines provide additional protection for people already infected with Covid-19”, says one of the study’s authors, Brazilian infectologist Julio Croda.

According to the study, among people who became infected with Covid-19 and were vaccinated, the risk of hospitalization and death was reduced by 90% with Pfizer/BioNTech and AstraZeneca immunizers, about 80% with Coronavac, and a little over 50% with the Janssen vaccine.

The other study, based on data collected in Sweden, goes in the same direction. The work shows that people who have had Covid maintain a high immunity for about 20 months. However, the risk of reinfection drops even further — about two-thirds — if individuals were vaccinated after the first infection.

Although these studies were carried out before the expansion of the omicron variant and the BA.2 subvariant — more contagious and resistant to vaccines — the scientific community considers that they bring important clues about the fight against the disease.

“Hybrid immunity, acquired after exposure to an infection and vaccination, can provide durable protection,” says Indian researcher Pramod Kumar.

^{With information from AFP}