A study by the UK Coronavirus Immunology Consortium (UK CIC) found T-cell immunity persisted for 6 months in a group of medical staff.
The study, published as an un peer reviewed preprint, is believed to be the most significant piece of research on the subject.
Unlike antibodies, which attach to the virus, T-cells attack cells infected with the virus, something known as a cellular immune response.
A number of studies have found SARS-CoV-2 antibodies in some patients wane after a few months. This study offers hope that cellular (T-cell) immunity could provide immunity that outlasts antibodies.
The researchers tested blood samples from more than 2,000 healthcare workers, including 100 who tested seropositive for SARS-CoV-2 in March and April 2020.
Among the 100 testing positive, the average age was 41, within a range of 22 to 65. 23 were men and 77 were women. None were hospitalised, 56 had mild or moderate symptoms and 44 were asymptomatic.
All 100 had a cellular immune response against SARS-CoV-2 six months after infection, although the response was 50% more pronounced in those who had experienced symptomatic disease. In addition, the magnitude of the T cell response at six months was strongly correlated with the magnitude of the peak antibody response.
This data is reassuring, said study author Paul Moss. “However, it does not mean that people cannot be re-infected. We need to have much larger population studies to show that”, he said.
The findings also have implications for vaccine development. Vaccines could be developed around proteins on the virus targeted by T-cells. Essentially, a vaccine might be able to trigger a T-cell response.
More on this:
UK CIC update (in English)
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