In a new study from Imperial College London, researchers found the first evidence of a protective role for T cells in COVID-19.
They found that high levels of pre-existing T cells, created by the body when infected with other human coronaviruses like the common cold, can protect against COVID-19 infection.
Their findings provide a blueprint for a second-generation, universal vaccine that could prevent infection from current and future SARS-CoV-2 variants, including Omicron.
The study began in September 2020 when most people in the UK had neither been infected nor vaccinated against SARS-CoV-2.
It included 52 people who lived with someone with PCR-confirmed SARS-CoV-2 infection and who had therefore been exposed to the virus.
The participants did PCR tests at the outset and 4 and 7 days later, to determine if they developed an infection.
Blood samples from the 52 participants were taken within 1-6 days of them being exposed to the virus.
The researchers found that there were much higher levels of these cross-reactive T cells in the 26 people who did not become infected, compared to the 26 people who did become infected.
These T cells targeted internal proteins within the SARS-CoV-2 virus, rather than the spike protein on the surface of the virus, to protect against infection.
Current vaccines do not induce an immune response to these internal proteins.
The researchers say that—alongside the existing effective spike protein-targeting vaccines—these internal proteins offer a new vaccine target that could provide long-lasting protection because T cell responses persist longer than antibody responses which wane within a few months of vaccination.
The study provides the clearest evidence to date that T cells induced by common cold coronaviruses play a protective role against SARS-CoV-2 infection.
These T cells provide protection by attacking proteins within the virus, rather than the spike protein on its surface.
The team says the spike protein is under intense immune pressure from a vaccine-induced antibody which drives the evolution of vaccine escape mutants.
In contrast, the internal proteins targeted by the protective T cells we identified mutate much less. Consequently, they are highly conserved between the various SARS-CoV-2 variants, including omicron.
New vaccines that include these conserved, internal proteins would therefore induce broadly protective T cell responses that should protect against current and future SARS-CoV-2 variants.
If you care about Covid, please read studies about plant extract that could inhibit COVID-19 virus, and findings of common drug for heart disease that could reduce COVID-19 risk.
For more information about health, please see recent studies about new antibody treatment for COVID-19, and results showing that COVID-19 antibodies can prevent reinfection for up to 6 months.
The study is published in Nature Communications. One author of the study is Dr. Rhia Kundu
Copyright © 2022 Knowridge Science Report. All rights reserved.
