Scientists at Imperial College London believe that the common cold may increase protection against COVID-19. However, they stipulate that no one should rely only on such immunity, because vaccines remain the best protection against SARS-CoV-2.
British researchers wanted to understand why some people get COVID-19 after being exposed to the coronavirus and others not. Since COVID-19 is caused by one type of coronavirus and some colds are caused by other coronaviruses, researchers wondered if immunity to one type could help fight the other. The study has been published in the journal Nature Communications.
Colds, COVID-19, and T cells
In carrying out the study, the researchers focused on a key part of the body’s immune system – T cells. Some of them kill cells infected by a specific threat, such as a virus that causes a cold. Once the cold has passed, some T cells remain in the body as a ‘memory bank’, ready to defend themselves the next time they encounter the virus.
In September 2020 – before vaccination even started – 52 people were tested who were not infected themselves but lived with people who had just tested positive for the coronavirus. Half of this group also developed COVID-19 during the 28-day study period, but half did not.
One-third of those who did not get sick had high levels of specific T-cells, the researchers explained, that they probably developed when the body was infected with another closely related human coronavirus – the most common being the common cold.
Cold Immune Bodies and Coronavirus
Exposure to SARS-CoV-2 does not always result in infection, and we wanted to understand why. We found that high levels of pre-existing T cells, created by the body during infection with other human coronaviruses, such as the common cold, could protect against COVID-19 infection, explains Dr. Rhia Kundu, one of the study authors.
The researchers believe the discovery could help understand how the body’s immune system fights the virus, but they emphasize that no one should rely solely on this defense, and vaccines remain a key element in defense against SARS-CoV-2. It would be a “serious mistake” to believe that anyone with a recent cold has automatic COVID-19 protection, they add, as not all colds are caused by coronaviruses.
Source: PAP / Bartłomiej Niedziński (London)