A new study from researchers at Boston-based Harvard Medical School found the spike protein of the SARS-CoV-2 virus may linger in long COVID-19 patients' blood for up to a year after infection. The findings reinforce a leading theory among scientists that lingering virus particles stimulate an immune system reaction that causes symptoms.
The latest findings, published Sept. 2 in the journal of Clinical Infectious Diseases, are based on researchers' analysis of plasma samples from 63 patients. Thirty-seven of the participants were diagnosed with post-acute sequelae of COVID-19, or long COVID-19. The rest of the cohort recovered after their acute infection. Blood samples were collected at least two times up to one year after testing positive.
The spike protein was detected in the majority of samples from long COVID-19 patients, including samples analyzed up to 12 months after acute infection.
"The presence of circulating spike supports the hypothesis that a reservoir of active virus persists in the body," researchers said.
David Walt, PhD, lead study author and professor of pathology at Harvard and Brigham and Women's Hospital in Boston, told The Wall Street Journal that some long COVID-19 patients had levels of viral spike protein a year after infection that were as high as earlier in their illness.
Two more updates on long COVID-19:
1. Long COVID-19 may be keeping between 2 million and 4 million Americans out of work, according to an Aug. 24 report from the Brookings Institute. Researchers estimated about 16 million working-age Americans are experiencing lingering effects of COVID-19, and of those, between 2 million and 4 million are out of work.
2. Psychological distress may increase long COVID-19 risk by up to 50 percent, according to a new study also led by researchers at Harvard. The findings are based on data from more than 54,000 people, 3,000 of whom were infected between April 2020 and November 2021. Researchers found participants with two or more types of distress prior to infection — such as depression, anxiety, worry, perceived stress and loneliness — were at nearly 50 percent increased risk for lingering symptoms.