If your Covid symptoms last more than a month, they may become persistent

2024-02-21 15:59:54
Persistent Covid-19 infections are much more common than previously thought: up to three in 100 infections last a month or more. These data come from a study published in ‘Nature’ that has analyzed the data of more than 90,000 people between November 2020 and August 2022 in the United Kingdom. The research further shows that some persistent infections had a large number of mutations, suggesting that they could act as reservoirs to seed new variants of concern. Likewise, people with persistent infections that lasted 30 days or more were 55% more likely to report having long Covid than those with more typical infections. It has long been thought that prolonged Covid-19 infections in immunocompromised people may have been the source of the multiple new variants that emerged during the coronavirus pandemic and seeded successive waves of infection, including the Alpha and Omicron variants. But until now the prevalence of persistent infections among the general population and how the virus evolves in these situations were unknown. To investigate this, researchers at the University of Oxford used data from the Office of National Statistics Covid Infection Survey (ONS-CIS), which tested participants about once a month. Of the more than 90,000 participants, 3,603 provided two or more positive samples between November 2020 and August 2022 in which the virus was sequenced. Of them, 381 people tested positive with the same viral infection over a period of a month or more. Within this group, 54 people had a persistent infection that lasted at least two months. Researchers estimate that between one in a thousand and one in 200 (0.1-0.5%) of all infections may become persistent and last at least 60 days. In some cases, people were still infected with viral variants that had become extinct in the general population. But the researchers found that reinfection with the same variant was very rare, probably because the host developed immunity to that variant and the variant reduced its frequency to very low levels after a few months. Of the 381 persistent infections, 65 had three or more PCR tests performed during the course of their infection. The majority (82%) of these people demonstrated viral rebound dynamics, experiencing a dynamic of high, then low, then high viral load. As Mahan Ghafari tells ABC Health, “this means that the virus retains the ability to actively replicate during these prolonged infections. We also found that these infections are more likely to report long Covid compared to non-long Covid infections. However, persistent infections also show interesting variations among themselves; Not all of them result in viruses with numerous mutations. “Some acquire very few mutations.” This expert adds that in addition to observing the greater probabilities of long Covid in these individuals, “we do not know if there are other health implications of these infections.” Thus, although other studies have shown that chronic infections with highly mutated viruses occur in certain immunocompromised individuals, such as those receiving cancer treatment or who have advanced HIV, “since we do not have access to the medical records of the participants in our study, we cannot definitively say whether they have other long-term health problems. Persistent infection is just one of many factors that contribute to long Covid. Additionally, people with persistent infections were 55% more likely to report having long Covid symptoms more than 12 weeks from the start of infection than people with persistent infections. more typical. “Our observations highlight the continued importance of community genomic surveillance both to monitor the emergence and spread of new variants, but also to gain an understanding of the natural history and evolution of new pathogens and their clinical implications for patients,” he says. Mahan Ghafari, author of the study. Spike protein Certain individuals showed an extremely high number of mutations, including mutations that define new variants of the coronavirus, alter the target sites of monoclonal antibodies, and introduce changes to the coronavirus spike protein. However, most individuals did not harbor a large number of mutations, suggesting that not all persistent infections will be a potential source of new variants of concern. «Although the relationship between viral persistence and long Covid may not be causal, our results suggest that persistent infections could be contributing to the pathophysiology of long Covid. In fact, many other possible mechanisms have been suggested, including inflammation, organ damage, and microthrombosis. Importantly, our results suggest that even if persistent infections are causing long Covid, they only explain a small proportion of all cases. In other words, persistent infection is just one of many factors that contribute to long covid », he comments.
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