Health News | Study: Protective T Cells Remain 20 Months After COVID-19

Gothenburg [Sweden], July 22 (ANI): Shortly after infection, patients infected with SARS-CoV-2 develop protective immune responses mediated by virus-specific T cells and antibodies. However, there is concern that immunity does not last, which could result in severe COVID-19 infection upon re-infection.

Anna Martner and co-authors from the University of Gothenburg report two major findings in the July 12 issue of Proceedings of the National Academy of Sciences (PNAS). First, several virus-specific T cell variants were detected in blood shortly after COVID-19 but then vanished after 10-12 weeks.

Also Read | Female Voices With Higher Pitch Have Younger-Looking Faces.

However, a subset of highly specialised T cells, which are designed to help eliminate infected cells, remained active in the blood of all previously SARS-CoV-2-infected patients. Even after a long period of observation, these T cells did not disappear or wane.

The findings could explain why patients who have been re-infected with SARS-CoV-2 have a lower risk of severe disease and death.

Also Read | COVID-19 Survivors Likely To Develop Heart Diseases, Diabetes in Three Months, Says Study.

Researchers from the University of Gothenburg and Sahlgrenska University Hospital collected 81 blood samples from hospital staff members who had mild COVID-19 in the first year of the pandemic, as well as uninfected controls. T cell reactivity to an inner part of SARS-CoV-2 (the virus nucleocapsid) was studied, capturing T cell responses that only occur after a natural infection.

More than 100 peptides from the nucleocapsid portion of the SARS-CoV-2 virus were administered to the blood samples. The researchers then looked at which T cell mediators (cytokines) were produced by blood cells to see how long T cell reactivity lasted after infection.

It was observed that a subgroup of specialized T cells (Th1 cells) that promote the destruction of virus-infected cells were active for at least 20 months after natural COVID-19. The infected patients also harboured several other types of T cells that reacted with SARS-CoV-2. These latter T cells disappeared from blood approximately 2 months after recovery from infection.

"While certain subsets of T cells disappear shortly after an infection, highly specialized T cells (T helper 1 cells) remain stably present in the blood to suggest that a vital aspect of protective immunity is functional years after COVID-19," says Anna Martner, Associate Professor of Immunology at the Sahlgrenska Academy. These results may explain why re-infection with SARS-CoV-2 only rarely translates into severe COVID-19. (ANI)

(The above story is verified and authored by ANI staff, ANI is South Asia's leading multimedia news agency with over 100 bureaus in India, South Asia and across the globe. ANI brings the latest news on Politics and Current Affairs in India & around the World, Sports, Health, Fitness, Entertainment, & News. The views appearing in the above post do not reflect the opinions of LatestLY)