This important discovery, published in the journal Nature, could lead to better vaccines, that not only protects against Covid and its variants, but also against coronaviruses that cause common colds, and to new emerging animal coronaviruses.
By designing vaccines that activate immune memory cells, known as T cells, to attack infected cells expressing this part of the virus’s internal machinery, it may be possible to eliminate Covid at the very outset which crucially could help stop it spreading.
The study analysed the immune responses in a large group of London-based healthcare workers from the beginning of the first wave of the pandemic.
In a subset of healthcare workers, who showed no sign of Covid infection (repeatedly testing negative by PCR and antibody tests) there was, however, an increase in T cells.
Rather than having avoided infection completely, the immune system of a subset of these healthcare workers appeared to be able to get on top of the virus before it managed to take hold – what’s known as an “abortive infection”.
Senior author Professor Mala Maini (UCL Infection & Immunity) said: “Our research shows that individuals who naturally resisted detectable SARS-CoV-2 infection generated memory T cells that target infected cells expressing the replication proteins, part of the virus’s internal machinery.
“These proteins – required for the earliest stage of the virus’s life cycle, as soon as it enters a cell – are common to all coronaviruses and remain ‘highly conserved’, so are unlikely to change or mutate.
“A vaccine that can induce T cells to recognise and target infected cells expressing these proteins, essential to the virus’s success, would be more effective at eliminating early SARS-CoV-2, and may have the added benefit that they also recognise other coronaviruses that currently infect humans or that could in the future.”
COVIDsortium is led by researchers at St Bartholomew’s and UCL Hospitals. The project was made possible by generous donations from individuals, charitable trusts, and corporations including Kenneth C. Griffin and The Guy Foundation Family Trust, enabled by Barts Charity.
Sharing this lovely #thankyou letter from a grateful patient who spent #Christmas Day at @WhippsCrossHosp - showing… https://t.co/zvR8P2IsCt