Scientists at Imperial College London believe that the common cold may increase protection against developing Covid-19. However, they warn that no one should rely on this type of protection alone, and that vaccines remain the best protection against infection.
Researchers set out to find out why some people get Covid-19 after contact with an infected person and others not. Covid-19 is caused by some type of coronavirus and some colds are caused by other coronaviruses, so scientists have wondered if being immune to one type of virus might help fight the other.
Researchers focused on a key part of the body's immune system, T cells. Some of them kill infected cells, such as the common cold virus. Once the cold has passed, some T cells remain in the body as a "memory bank", ready to defend against the next attack. The results of the analyzes were published in the journal "Nature Communications".
In September 2022, before the advent of SARS-CoV-2 vaccines, researchers tested 52 people who were not infected 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 and half did not.
One-third of those who did not get sick had high levels of specific T cells. The authors of the study explain that they likely formed when the body was infected with another closely related human coronavirus - the most common cold.
"Being exposed to the SARS-CoV-2 virus does not always result in infection, and we wanted to understand why. We found that high levels of pre-existing T cells, formed by the body during infection with other human coronaviruses, such as the common cold may protect against Covid-19 infection, "says one of the study's authors, Dr. Rhia Kundu.
These findings provide new insight into how the body's immune system fights the virus. However, they emphasize that vaccination is still the best form of protection against the disease and severe course of the disease,and that you should not rely on automatic protection from a recent infection.