Immunity for the common cold coronaviruses may ward off severe covid-19. According to a laboratory experiment a strong T-cell response against the coronaviruses including the ones that cause the common cold-like symptoms was linked to greater covid-19 immunity.

We look at what this means:

If you have a good immune response to the common cold coronovirus you are more likely protected against covid-19.

Increasing the hopes that a pan-coronavirus vaccine could be achieved.

Ricardo da Silva Antunes at La Jolla Institute for Immunology in California analysed blood samples collected from 32 people between 2016 and 2019, before covid-19 emerged.

Samples were taken from each person over six months to three years.

The team wanted to see how the immune cells in these samples responded to four different coronaviruses that cause common cold-like symptoms as well as the original SARS-CoV-2 strain. The common cold and flu are all SARS Covid pathogens. Which can move across populations as fast as Covid 19.

The coronavirus class is wide. Several strains are known to infect humans. Of these, four viruses cause common cold-like symptoms. Including SARS-CoV, which causes severe acute respiratory syndrome (SARS); MERS-CoV, which causes Middle East respiratory syndrome (MERS); and SARS-CoV-2, the cause of the ongoing pandemic.

Da Silva Antunes says "it was important to use samples taken before the pandemic. This means that when we’re looking at our results, we know that they are caused by pre-existing immune memory and that they’re not contaminated by people’s immune responses to SARS-CoV-2.”

Covid 19 has similar genetic sequences to the four common cold-like coronaviruses, says da Silva Antunes. Studies previously suggest that stronger T-cell responses induced by prior coronaviruses may protect against SARS-CoV-2.

The researchers combined the participants’ blood with peptides – strings of amino acids – from the different common cold-like coronaviruses.

Immune responses are typically triggered by the body recognising the peptides of a virus. They measured the T-cell responses in the blood when exposed to these viruses.

Looking at multiple samples from each participant, the researchers found the T-cell and antibody responses were stable and persistent for all four common cold-like coronaviruses.

By looking at the T-cells, some of which are more likely to be activated by recent re-infections, they determined these immune responses weren’t due to regular re-infections. Instead, this immune response may be relatively stable.

Da Silva Antunes speculates that if these common cold-like coronaviruses elicit similar immune responses, it may generate a stable immune memory.