A lab-based study has found that a virus that causes the common cold can trigger an innate immune response against SARS-CoV-2, the virus responsible for Covid-19.
In theory, infections with the common cold virus could inhibit the transmission of SARS-CoV-2 among members of a population and reduce the severity of infections.
Further research could lead to control strategies or treatments that exploit such interactions between viruses.
For decades, scientists have been hunting for a cure for the common cold, with little success.
However, recent research hints that this bothersome — though usually mild — infection may be a hidden ally in the fight against pandemic viruses such as influenza and SARS-CoV-2.
Human rhinoviruses (HRVs), which cause more than half of all common colds, are the most widespread respiratory viruses in humans.
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Previous researchTrusted Source suggests that HRVs may have inhibited the spread of the influenza A virus subtype H1N1 across Europe during the 2009 flu pandemic.
Experts believe that the HRVs did this by inducing human cells to produce interferon, which is part of the body’s innate immune defenses against viral infection.
Research has shown that SARS-CoV-2 is susceptibleTrusted Source to the effects of interferon.
This finding led scientists at the MRC-University of Glasgow Centre for Virus Research in the United Kingdom to speculate whether HRVs could help combat the spread of SARS-CoV-2 and limit the severity of infections.
To find out, the researchers infected cultures of human respiratory cells in the lab with either SARS-CoV-2, an HRV, or both viruses at the same time.
The cultures closely mimicked the outer layer of cells, called the epithelium, that lines the airways of the lungs.
SARS-CoV-2 steadily multiplied in the cells that the team had infected with this virus alone.
However, in cells also infected with HRV, the number of SARS-CoV-2 virus particles declined rapidly until they were undetectable just 48 hours after the initial infection.
