vaccines and that the condition may be caused by a dysfunction of the
immune system — possibly explaining why some people experience symptoms
for months while others recover and resume normal lives.
The study compared people who already had long COVID with people who had
recovered from the virus. Both groups had not yet been vaccinated prior to
the study. When researchers analyzed blood samples after people received an
initial vaccine dose, they found that people with long COVID and people who
had already recovered from the virus had similar immune responses at first.
But after 8 weeks, the long COVID group’s immune response remained
elevated, while the other group’s response had declined.
The long COVID group also showed an extra immune response that tried to
fight the virus in a secondary way that researchers didn’t expect. Both
groups showed an initial increase in their blood of antibodies that
primarily target what’s known as the “spike” protein of the coronavirus,
which allows the virus to invade healthy cells. But the long COVID group
also showed a prolonged increased immune response that tried to fight the
part of the virus related to how it replicates.
