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A previous infection with the omicron subvariants BA.1 or BA.2 protects vaccinated persons four times more once morest infection with BA.5 than no infection. This is shown by a study from Portugal. The research was published in the New England Journal of Medicine.

The researchers had access to the national registry of Covid-19 cases. All SARS-CoV-2 infections in the population aged 12 and over residing in Portugal were recorded. The virus variant of each infection was determined taking into account the date of infection and the variant dominant at the time.

Infection with omicron variants BA.1 and BA.2 protects once morest BA.5

“Vaccinated people who have been infected with the omicron subvariants BA.1 and BA.2 have regarding four times the protection once morest infection with the subvariant BA.5, which has been circulating since June, than vaccinated people who were never infected “, explains co-study leader Prof. Luís Graça from the Instituto de Medicina Molecular João Lobo Antunes and the Faculty of Medicine of the University of Lisbon. Infection with the omicron variants BA.1 and BA.2 thus protects once morest BA.5.

Infections in 2020 and 2021 caused by infection with earlier variants of the SARS-CoV-2 virus (alpha and Deltavariants) also confer protection once morest infection from the newer Omicron variant, although this protection is not as high. The protection of infected vaccinees is called hybrid immunity.

Shows benefit of adapted vaccines

The results are also important for the evaluation of the vaccines adapted to Omicron-BA.1 and allow to anticipate their usefulness, adds Luís Graça on the relevance of the study. Corresponding vaccines have been available in Germany since September 5th. Vaccines adapted to BA.4 and BA.5 are to be approved from October.

The benefit of a possible second booster vaccination or fourth vaccination is currently being discussed in Germany. It should not take place before six months following the last infection or vaccination. The STIKO recommends them for people over 60 years of age and people over 5 years of age with an existing underlying disease. Since protection once morest a serious illness is particularly important, they should not postpone a possible vaccination date in order to wait for a vaccine that is even better adapted to the currently circulating variants.