Scientists at Queen Mary University of London in the UK have proven the presence of long-term immunity in those who have had a mild or latent coronavirus infection. This is reported in an article published in the journal Science Immunology.
The researchers analyzed blood samples from 136 healthcare workers for antibodies and T-lymphocytes. Volunteers have had mild or asymptomatic COVID-19 infection since March 2020. It turned out that 89 percent of healthcare workers had neutralizing antibodies 16-18 weeks after infection. Most of them also showed T cells targeting different parts of the virus.
Some people had T-lymphocytes, but no antibodies, while others did the opposite. However, 66 percent of healthcare workers had high levels of protective antibodies. T-cell responses tended to be more pronounced in people with the classic symptoms of COVID-19. Asymptomatic infection resulted in weaker T-cell immunity.