A new study by researchers at Brigham and Women’s Hospital suggests that a lingering infection may be responsible for why some people experience long COVID symptoms, while others do not. The research analyzed more than 1,500 blood samples and found that 43% of participants with symptoms affecting the heart, lungs, muscles, or nervous system showed signs of persistent infection. This study finds link between persistent infection and long COVID symptoms
The findings, published in Clinical Microbiology and Infection, were led by Dr. Zoe Swank, a postdoctoral fellow in the Department of Pathology. According to Dr. Swank, identifying individuals with ongoing viral symptoms caused by remnants of the virus in their bodies could help doctors treat them with antiviral medications, potentially easing their symptoms.
The research team examined 1,569 blood samples from 706 individuals, including 392 participants from the RECOVER Initiative, supported by the National Institutes of Health. All participants had previously tested positive for COVID-19. The researchers employed an advanced testing method to detect SARS-CoV-2 proteins—either whole or partial—circulating in the blood.
They discovered that people reporting long COVID symptoms were twice as likely to have these viral proteins present in their bloodstream compared to those who did not report ongoing symptoms. The test used in the study, called Simoa, is highly sensitive, and capable of detecting individual molecules.
Common symptoms of long COVID reported by participants included fatigue, brain fog, muscle pain, joint pain, headaches, loss of smell or taste, sleep problems, and gastrointestinal issues. Notably, 43% of individuals with symptoms affecting the cardiopulmonary, musculoskeletal, and neurologic systems tested positive for viral proteins within 14 months of their COVID-19 infection, while only 21% of those without long COVID-19 symptoms showed similar biomarkers.
While these findings suggest that persistent infection may be behind many long COVID cases, it is not the only potential cause. Dr. David Walt, a professor of pathology and the study’s principal investigator, noted that more than half of the patients with long COVID symptoms did not have viral proteins in their blood, indicating that other factors, such as immune system damage, could be contributing to their ongoing health issues.
“This study adds to the growing evidence that more than one mechanism could be driving long COVID,” said Walt. He added that other viral infections, like Ebola and Zika, have also been linked to post-acute illness syndromes, making persistent infection a plausible explanation for long COVID in some patients.
So, This study finds link between persistent infection and long COVID symptoms but the study’s findings underscore the need for further research to better understand the causes of long COVID and develop effective treatment options for those suffering from its symptoms.