AGI – The risk of a second SARS-CoV-2 infection appears to be significantly reduced in the ten months following the first manifestation of the disease. The hypothesis emerges from a study, published in The Lancet Healthy Longevity journal, conducted by scientists at University College London, who examined cases of Covid-19 infection in over two thousand residents and staff members of nursing homes. As part of the Vivaldi study, the team evaluated the antibody rates of 682 people with an average age of 86 and 1,429 employees from 100 nursing homes in England.
Between June and July, about a third of the participants were infected with the new coronavirus disease, and the researchers analyzed the results of PCR tests performed once a week for staff and once a month for residents. The scientists found that residents who had contracted a previous infection had 85 percent less likely to test positive again compared to those who have never had Covid-19. For staff members, the percentage dropped to 60 percent.
Experts say these data show strong protection, although the two values may not be directly comparable, as the residents who tested positive for the antibodies probably represented a particularly strong group physically given their resistance to the first wave of the pandemic. “I think this low rate of infection probability is very encouraging – underlines Maria Krutikov of University College London – it is also good news for nursing home visitors and for the most vulnerable groups in general”. In a separate study, the authors are evaluating the vaccine’s effectiveness.
“Our work represents aunique opportunity to examine the protective effect of natural infection in this cohort – says Laura Shallcross of University College London – the next step will be to evaluate the duration of immunity after natural infection and vaccination and to verify if the protective effect is maintained against current and emerging variants “.