A Omicron infection coupled with vaccination against Covid-19 would be the best combination against a potential infection by the currently circulating subvariants, namely BA.5 and possibly BA.4. This is the observation made by a study by the Institute of Molecular Medicine based in Portugal, the results of which were published in the New England Journal of Medicine this Wednesday, August 31. One of the first to analyze the probability of being infected by the sub-variant currently in circulation in vaccinated people, even indicates the institute in a communicated.
“Vaccinated persons who have been infected with the Omicron BA.1 and BA.2 subvariants have protection against infection with the BA.5 subvariant, which has been circulating since June, about four times higher to that of vaccinated people who have not been infected at any time”explains Luis Graça, co-responsible for the study.
Conventional wisdom is that previous infection with omicron subvariant BA.1 or BA.2 does notprotect against BA.5, but data from Portugal show considerable protection against BA.5 infection from previous BA.1 or BA.2 infection. https://t.co/1qXPAENSynpic.twitter.com/qKpbuF2DDu
—NEJM (@NEJM) August 31, 2022
Protection also offered by strain variants of Covid-19, i.e. Alpha and Delta. “Infections in 2020 and 2021 that occurred by infection of earlier variants of the SARS-CoV-2 virus also confer protection against infection by the newer Omicron variant, although this protection is not as high as that of individuals infected with the BA.1 and BA.2 variants in early 2022″he continues.
Challenge for new vaccines
If the current Covid vaccines are less effective in blocking Omicron infection compared to earlier variants, the new ones currently in clinical development or just authorized by health agencies (Moderna and Pfizer-BioNTech) are based on the BA.1 subvariantdominating in January and February 2022. Which would potentially allow for a better immune response.
These results, obtained through access to the national register of Covid-19 cases in Portugal, thus allow “to anticipate the benefit of appropriate vaccines” against Covid-19 and nevertheless demonstrate once again the importance of vaccination, which continues to avoid severe forms of the disease.
Sources:
- Risk of BA.5 Infection among Persons Exposed to Previous SARS-CoV-2 Variants, New England Journal of MedicineAugust 31, 2022
- Previous variants of SARS-CoV-2 provide protection against Omicron BA.5 infection, Institute of Molecular MedicineAugust 30, 2022
