LONDON: The speed at which a person’s immune system responds to infection with COVID-19 plays a key role in determining the disease’s long-term severity, according to a new UK study.
Researchers from Cambridge University studied 207 people who tested positive for COVID-19 over three months, finding that subjects with mild or no symptoms offered a rapid, strong immune response soon after infection.
The 207 people in the experiment ranged from asymptomatic healthcare workers to patients requiring ventilation.
The team analyzed blood samples taken regularly over three months, and compared them with others taken from 45 healthy people.
The healthiest in the study produced anti-virus cells in larger numbers than the patients with severe COVID-19 infections. The first group also developed immunity cells within the first week of infection.
But the people with severe cases who required hospitalization were found to have an impaired immune response, which frustrated the body’s attempts to fight the virus, leading to more severe infection.
This weakened response to COVID-19 is characterized by inflammation of several organs, which starts right after a person catches the disease.
Scientists say abnormalities in immune cells could explain the slower response to viral infection as well as the organ inflammation.
These two crucial factors could contribute to the severity of the disease and the phenomenon known as long COVID, where people feel symptoms and have health issues many months after contracting and recovering from the virus.
“Our evidence suggests that the journey to severe COVID-19 may be established immediately after infection, or at the latest around the time that they begin to show symptoms,” said Dr. Paul Lyons, a Cambridge academic and senior co-author of the study.
“This finding could have major implications as to how the disease needs to be managed, as it suggests we need to begin treatment to stop the immune system causing damage very early on, and perhaps even pre-emptively in high-risk groups screened and diagnosed before symptoms develop.”