It has long been thought that prolonged COVID-19 infections in immunocompromised individuals may have been the source of the multiple new variants that arose during the coronavirus pandemic and seeded successive waves of infection, including the Alpha and Omicron variants. But until now, the prevalence of persistent COVID-19 infections in the general population and how the virus evolves in these situations remained unknown.
To investigate this, the researchers used data from the Office for National Statistics Covid Infection Survey (ONS-CIS), which tested participants approximately monthly. Of the 90,000+ participants, 3,603 provided two or more positive samples between November 2020 to August 2022 where the virus was sequenced. Of these, 381 individuals tested positive with the same viral infection over a period of a month or longer. Within this group, 54 individuals had a persistent infection which lasted at least two months. The researchers estimate that between one in a thousand to one in 200 (0.1-0.5%) of all infections may become persistent, and last for at least 60 days.