New Delhi: The COVID-19 virus can persist in the blood and tissue of the infected patients for more than a year after the acute phase of the disease has ended, according to a study.
The research, presented at the Conference on Retroviruses and Opportunistic Infections (CROI) held from March 3 to 6 in Colorado, US, offers potential clues to why some people develop long COVID, a condition in which the symptoms linger for months.
Early in the pandemic, COVID-19 was thought to be a transient illness. But a growing number of patients, even those who had previously been healthy, continued having symptoms, such as, brain fog, digestive problems and vascular issues, for months or even years.
The researchers looked at blood samples from 171 people who had been infected with COVID using an ultra-sensitive test for the COVID “spike” protein and found the virus was still present up to 14 months later in some people. Among those who were hospitalised for COVID, the likelihood of detecting the COVID antigens was about twice as high as it was for those who were not.
Since the virus is believed to persist in the tissue reservoirs, the scientists turned to UCSF’s Long COVID Tissue Bank, which contains samples donated by patients with and without long COVID.The researchers found it in the connective tissue where immune cells are located, suggesting that the viral fragments were causing the immune system to attack. In some of the samples, the researchers found that the virus could be active.
Peluso said more research is needed to determine whether the persistence of these fragments drives long COVID and such associated risks as heart attack and stroke.