The rhinovirus, which causes one of the most common colds, does not tolerate the new coronavirus in body cells. This is evident from a Scottish study from the University of Glasgow. The rhinovirus is so widespread that it could help suppress Covid-19, it concluded.
Some viruses are known to compete to infect someone. We have to imagine the cells in our nose, throat, and lungs as a row of houses, the BBC visually puts it. Once a virus is in, it can either leave the door open to other viruses or block the door to keep the house to itself. The flu virus excels in the latter, for example.
There has long been speculation about Sars-CoV-2, the new coronavirus that causes Covid-19, in terms of its interaction with other viruses. Researchers from the University of Glasgow have now organized ’a camp’ between Sars-CoV-2 and the rhinovirus in the laboratory. The scientists infected a replica of our airways, made from the same kind of cells, with Sars-CoV-2 and with the rhinovirus.
It turned out that if both viruses are released simultaneously, only the rhinovirus is successful. If the rhinovirus gets a 24-hour head start, Sars-CoV-2 has no chance at all. And even if Sars-CoV-2 is first allowed 24 hours to set up, it will be driven out of the cells by the rhinovirus. In other words: the rhinovirus always wins against the new coronavirus.
“Sars-CoV-2 never gets off the ground and is badly slowed down by the rhinovirus,” researcher Pablo Murcia confirms to BBC News. “This is absolutely fascinating because, with a high prevalence of the rhinovirus, it can stop new Sars-CoV-2 infections.” Something similar may have happened as early as 2009 when a major outbreak of the rhinovirus is said to have slowed down swine flu in certain parts of Europe.
Other experiments also showed that the rhinovirus causes an immune response in the infected cells, preventing Sars-CoV-2 from making copies of itself. If the scientists block that immune response, the viral load of Covid-19 will be as high as if the rhinovirus were not present.
According to the study published in the Journal of Infectious Diseases, once the cold is over and the immune response diminishes, the risk of Covid-19 infection returns. The positive effect of the rhinovirus is therefore limited in time. According to Murcia, the interaction between viruses can indeed slow down the spread of Sars-CoV-2, but “the maximum effect will have to come from vaccinations”.
The rhinovirus is “very contagious” and can play a particularly beneficial role in the fight against Covid-19 in the fall and winter because those are the cold seasons, adds Professor Lawrence Young of Warwick Medical School.
It remains to be seen how the viruses will relate to each other during the following winters. For example, other infections that were suppressed by the corona pandemic could resurface. “We could see flu spikes or spikes in other respiratory viruses and pathogens,” warned Dr. Susan Hopkins of Public Health England of a potentially “hard winter” ahead of us.