Covid-19 infection upon re-infection. Anna Martner and co-authors from the University of Gothenburg report two major findings in the July 12 issue of Proceedings of the National Academy of Sciences (PNAS), the first one being that several virus-specific T cell variants were detected in blood shortly after Covid-19 but then vanished after 10-12 weeks.
While a subset of highly specialised T cells, which are designed to help eliminate infected cells, remained active in the blood of all previously SARS-CoV-2-infected patients.
Interestingly, despite a long period of observation, these T cells did not disappear or wane and the findings explain why patients who have been re-infected with SARS-CoV-2 have a lower risk of severe disease and death.
Researchers from the University of Gothenburg and Sahlgrenska University Hospital collected 81 blood samples from hospital staff members who had mild Covid-19 in the first year of the pandemic, as well as uninfected controls.