The common cold may offer people protection from severe Covid19 infections, according to a new study, offering a slim ray of relief amid a rapidly worsening global pandemic.
Published in Oxford’s Journal of Infectious Diseases, the study found that in cases of co-infection, where an individual is infected by the novel coronavirus as well as the rhinovirus that causes common colds, the rhinovirus can outcompete the novel coronavirus, suppressing the coronavirus and preventing a severe Covid19 infection. This might reduce the number of new cases among the population during cold season, as if one is exposed to the novel coronavirus while they already have a cold, they’re protected against the worst effects of Covid19.
Co-infections are quite common, experts note. “The cells lining our throat and lower airways are exposed to the environment around us, making them a prime target for co-infection by respiratory viruses,” Matthew James, from the School of Medicine, Dentistry and Biomedical Sciences at the University of Belfast, Northern Ireland, who was not involved in the study, wrote in The Conversation.
When an infection occurs, the cells in the infected individual’s body produce interferons, which James described as “virus-killing molecules.” While rhinoviruses can continue to replicate even in the presence of interferons, most other respiratory viruses, including the novel coronavirus, struggle to do so. And rhinoviruses, in fact, trigger the production of interferons not only at a much faster speed than other viruses but also in greater quantities. This prevents interferon-sensitive viruses, like the one that causes Covid19, from being able to replicate further.
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The researchers behind the study confirmed this by infecting human cells in a laboratory with both viruses. Since an individual would seldom be infected by both viruses at exactly the same time, the researchers infected the human cells with one of the two viruses 24 hours before introducing the other, in order to make their findings more applicable to real-life conditions. They found that the rhinovirus was able to stop the novel coronavirus from replicating irrespective of which virus was introduced first.
Given how common the ‘common cold’ is, the researchers believe their study indicates a potential reduction in the severity of Covid19 in the global population. “These findings have important implications. … Given the high transmissibility and prevalence of [rhinoviruses], this effect might have an impact on the disease burden caused by Covid19 at the population scale,” the study notes.
However, catching a cold isn’t an alternative to vaccination — while the common cold can offer protection from Covid19, it only lasts as long as the cold itself.
