A recent study published in the New England Journal of Medicine has shown that vaccinated people who were infected by the first Omicron subvariants have four times greater protection than the unvaccinated who did not catch the infection. Dr. Luis Graca, a professor at the University of Lisbon, revealed that vaccinated people who were infected by Omicron subvariants BA.1 and BA.2 had a greater degree of protection against infection with subvariant BA.5, i.e., four times greater than the vaccinated people who were not infected at any time.

Furthermore, she added that the findings of the study are very crucial because the adapted vaccines that are in clinical development and evaluation are based on the BA.1 subvariant of the virus, which was a dominant variant in infections in January and February 2022.

Meanwhile, Dr. Manuel Carmo Gomes, associate professor at the University of Lisbon, explained that the study demonstrated that previous infection in vaccinated people continued to confer immune protection against the variants that are known for their ability to evade the immune response, such as the subvariant currently dominant. 

(Source: https://www.livemint.com/science/health/do-vaccinated-people-infected-by-omicron-have-greater-protection-here-s-what-study-shows-11662101395371.html )