Long COVID Linked to Reactivated Viruses

When COVID-19 knocks you down, it may wake up viruses your body thought it had long ago quieted, a new study suggests. Researchers analyzed 1,154 unvaccinated patients hospitalized with COVID between May 2020 and March 2021 and found that nearly half showed signs of at least one dormant virus roaring back to life within 40 days of admission, Smithsonian reports. Eleven viruses were implicated, including herpesviruses like Epstein-Barr, cytomegalovirus, and HSV-1, along with usually ignored anelloviruses, per ABC News.

These reactivations weren't just biochemical background noise. Patients with reawakened viruses showed more inflammatory markers and immune activation, and reactivated anelloviruses were linked to long COVID symptoms such as fatigue and physical impairment. The work, published in Nature, challenges the idea that only people with weakened immune systems see such viral comebacks, though it's still unclear how this plays out in vaccinated people, those with mild or moderate COVID, or those infected with newer variants. The next step, say the authors, is testing whether spotting and treating these reactivated viruses can blunt severe COVID or long COVID.