One of the mysteries of COVID-19 is why some people appear to have “immunity” despite exposure to the SARS-CoV-2 virus. Scientist from Imperial College London (United Kingdom) already published research results showing that immune cells created to fight the common cold can protect the body from the risk of SARS-CoV-2 infection.
When you have a cold, your immune system make antibodies and now, T . cells (aka immune system memory cells) will seek and destroy infected cells. T cells stay in the body longer than other antibodies and help prevent colds from coming back.
Corona virus is responsible for 15 – 30% of flu cases. This new study shows that T cells that have survived a previous cold caused by a coronavirus infection can fight off SARS-CoV-2 infection.
This is an observational study published in Nature Communications (a British multidisciplinary scientific journal). The study began in September 2020 – the time before a COVID vaccine was released. The scientists took blood samples from 52 people living with those who tested positive for COVID-19 by PCR. These subjects were tested by PCR on days 1, 4, and 7 of the study.
Scientists analyzed these blood samples to determine levels of T cells from previous coronavirus infections.
Half of the people in the study later tested positive for SARS-CoV-2, while the other half were not infected.
The coronavirus can cause many illnesses, including the common cold. Illustration.
Dr Rhia Kundu, of the Royal National Heart and Lung Institute, the study’s author, said exposure levels between the two PCR-negative and PCR-positive groups were similar.
The researchers found that people without SARS-CoV-2 had significantly higher levels of cross-reactive T cells. These memory cells target the internal proteins of the SARS-CoV-2 virus and prevent the virus from growing.
Dr. Arturo Casadevall, chair of the Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, comments: “This is a small study, but it has very interesting findings and is consistent with other data that exposure to the coronavirus can affect a person’s susceptibility to COVID-19.”.
Dr. Casadevall added: “This study reinforces the view that a person’s immune history, and in particular previous infection with other coronaviruses, is a key factor in determining the risk of COVID-19 infection.”.
Opening new directions for vaccine development
Current vaccines target spike protein on the surface of SARS-CoV-2 and stimulates the production of antibodies specific to the spike protein. Cross-reacting T cells target proteins within the virus.
The spike protein on the surface of the virus often mutates and creates new variants. The researchers suggest that in addition to producing a vaccine that targets the spike protein, we should develop a second-generation vaccine that targets the protein in the virus. Vaccines that stimulate T cell production tend to provide longer lasting immunity than vaccines that only stimulate antibody production.
Dr Kundu says: “Developing a vaccine that targets other parts of the virus that is immutable will provide a better basis for the immune system to fight off variants that may emerge later. This vaccine could be the next step.” in a vaccination campaign to control diseases caused by the SARS-CoV-2 virus”.
The Imperial College London team is currently working with other research groups to develop and test a second-generation vaccine.
Vaccines are still the most effective way to prevent COVID-19. Photo: Blue Planet Studio/Shutterstock.
Don’t just rely on colds
Dr. Simon Clarke, Associate Professor of Cellular Microbiology, University of Reading (UK) says: “It is a serious mistake to think that anyone who has recently had the flu may not have contracted Covid-19, as the coronavirus only accounts for 15 to 30 percent of flu cases.”.
Other experts say other variables, such as ventilation, will also have an impact on whether people in the study will catch COVID-19.
Dr Kundu repeated this message: “Getting a cold doesn’t mean you have these T cells, and vaccination is still the best protection against infection with the SARS-CoV-2 virus.”.
(Source: Medical News Today, The Week)
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