BEING infected with the omicron variant of the coronavirus may give some protection against flu.
Martin Michaelis at the University of Kent in the UK and his colleagues collected bronchial cells from a person with emphysema, a condition where the lungs' air sacs are damaged, but the bronchi airways are unaffected.
The cells were extracted as part of a standard diagnostic or treatment procedure. With the bronchi being unaffected by emphysema, the results are expected to apply to people without the condition, according to Michaelis.
In a laboratory study, the bronchial cells were infected with the delta variant of the SARS-CoV-2 coronavirus or one of two omicron subvariants, BA.1 or BA.5. As a control, the researchers treated some cells with a saline solution.
After two days, the team exposed all the cells to the H1N1 strain of influenza virus, which circulates every winter.
One day later, the researchers measured the H1N1 levels in all the cells. In the control cells and those infected with the delta variant, H1N1 levels increased roughly 10,000-fold (bioRxiv, doi.org/jc2b). This is compared with no increase in the cells that contained either omicron subvariant.
The team also found that the cells containing the omicron subvariants produced a protective immune response called the interferon response, which is known to reduce the replication of flu viruses. Among the control cells and those infected with the delta variant, this response was much lower and insufficient to suppress H1N1 replication.
We don't advise people to purposely get infected with covid-19 to protect against influenza
The findings may be reflective of changing SARS-CoV-2 and flu infection rates over the pandemic. “Following the lifting of restrictions in July 2021 in England, we saw a delta wave accompanied by an increase in influenza-like illnesses,” says Michaelis. “But then, since omicron BA.1 became dominant, influenza-like illnesses dropped and have stayed low.”
However, this could be due to people being more careful to avoid infections during winter, he says.
Understanding how covid-19 variants trigger varying immune responses may help researchers more quickly understand the potential impact of new variants.
“We, of course, don't advise people to purposely get infected with covid-19 to protect against influenza. With SARS-CoV-2 infection, there's always a chance you could die,” says Michaelis.