Enlarge /. Young children are returning to kindergarten after the COVID-19 lockdown.
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Our immune systems may soften in our comfortable COVID bladders.
Physical distancing, lockdowns, masking, and temperamental disinfection mean we come into contact with fewer garden variety germs than normal. This year's flu season has been canceled in principle.
While this seems like a welcome change from seasonal ailments and annoying runny nose, experts fear that our immune system could lose its defenses in the doldrums. And with the usual microscopic suspects awaiting a return to a sense of normalcy, it could mean nasty cold outbreaks and flu-like illnesses appear in our post-COVID future – those that may be unavoidable even if we carry on with some of our COVID precautions.
That seems to have happened in Hong Kong. In an analysis published in the journal Emerging Infectious Diseases, researchers found a dramatic outbreak of upper respiratory tract infections shortly after the children returned to schools and daycare in October 2020. The outbreaks broke out despite teachers and students still following strict COVID precautions.
“Staff and students wore face masks at all times. The lunch break was canceled, desks were distributed and group activities were limited, ”the researchers noted.
By the end of November, the researchers had counted 482 outbreaks of upper respiratory tract infections in schools. Of the outbreaks, 308 were in elementary schools and 149 in kindergartens, daycare centers and kindergartens. The remaining 25 were in secondary schools. With the widespread outbreaks, officials demanded nationwide school closings in mid to late November.
When examining laboratory tests on the specific germs behind the snot attack, the researchers found no infections with the novel coronavirus SARS-CoV-2 and no infections with influenza viruses. Instead, the tests pointed to rhinoviruses and enteroviruses – culprits of the common cold and other similarly mild infections.
The researchers believe that the outbreak of troublesome insects was due to immune responses in the children waning, while face-to-face learning largely ceased between January and late September. A cross-sectional survey had previously shown that 75 percent of school children had no contact with people outside of their household during their school days.
During this time, the number of colds and flu-like illnesses fell. "The population's vulnerability to rhinoviruses and other respiratory viruses, including influenza viruses, may have increased over time as individuals underwent intense social distancing, including school layoffs, in response to the COVID-19 pandemic," the researchers suggest. "This would have increased the transmission potential when schools resumed."
They note that a few weeks after schools reopened in England in September, there was a similar rise in adult colds.
"Non-pharmaceutical interventions can be different"
Regarding the spread of the virus with the COVID-19 precautionary measures in place in the reopened schools, the researchers have a different hypothesis: Basically, the COVID precautionary measures do not work well against cold germs. For example, face masks have been shown to successfully block coronavirus and influenza virus – but are less effective at blocking rhinoviruses. And rhinoviruses are tougher than coronaviruses and influenza viruses when it comes to withstanding disinfectants.
In general, different respiratory viruses use the same set of modes of transmission (surfaces, respiratory droplets, etc.), but “How much each mode contributes to the transmission of a particular virus remains unclear; Therefore, the effectiveness of certain non-pharmaceutical interventions may differ between viruses, ”the researchers write. In other words, masks and disinfectants may be highly effective against the flu virus and SARS-CoV-2, but may not be as effective against your standard snotchildren germs.
"Our results highlight the increased risk of the common cold virus in locations where schools were closed or laid off for extended periods of time during the COVID-19 pandemic," the researchers conclude.