“In other words, people who have Covid-19 cannot assume that they are protected from reinfection, even if they have been fully vaccinated.”Kata Dr Recio, dari Institut Catala de Salut, Tarragona di Spanyol.
“Nevertheless, both previous infection with other variants and vaccination appear to protect in part against severe disease and hospitalization in those with Omicron.,” he added.
He said monitoring of reinfection in fully vaccinated people was important, and would help in the search for vaccine-evading variants.
Covid reinfection increased sharply in December 2021 after a much more infectious variant of Omicron emerged, and there was another increase when a slightly different version, called BA.2, appeared in early March.
Prior to that, 1% of all cases recorded in the UK were labeled as a second infection but now it has risen to 11%. Most likely people were infected by the Alpha or Delta variants and then infected again by the more contagious Omicron. Scientists predict that eventually everyone will contract Covid twice, and possibly more during their lifetime.