Social distancing, wearing masks, and limiting group gatherings are all proven measures to control the spread of Covid-19. If more people follow those safety restrictions actively, the pandemic would be at a much better stage than it currently is. Though, Covid-19 policy measures brought unexpected side effects to the public health sphere. Transmission of other common viruses has hit record lows. Why has this happened, and what will the implications be when the pandemic comes to a close?
As you may expect from a year when hand sanitizer was scarcely available, and face masks were a top-selling e-commerce item, common illness plummeted in 2020. As Covid-19 raged, annually recurring viruses like the flu, norovirus, respiratory syncytial virus, as well as common bacterial infections like whooping cough and pneumonia, were recorded far less than usual. It seems the vast reduction in human contact, eating around others, and general isolation caused the transmission of these ailments to occur rarely.
Winter in the United States is typically plagued with rises in respiratory illness and flu infections. This chart by Biofire, a website designed to track trends in various infectious pathogens, demonstrates the abrupt fall in pathogenic detection following Covid-19 restrictions in mid-March. As states resumed their economies and schools reopened their doors, you can see a slight rise in infections, but nothing nearly as high as infections before the pandemic. Last year, the pathogens tracked in this chart were detected three times more than what is seen today.
While an interesting side effect of our ongoing isolation, what are the ramifications of lowered viral detection for the months to come? We should expect a heavy-handed return of these diseases once Covid-19 restrictions are lifted. People will likely begin to contract these diseases in droves once regular societal interaction resumes because any natural immunity to the viruses or bacteria may have been lost during the year in isolation. The old adage that being too clean may be a bad thing rings true in this scenario.
When people return to everyday life, the viruses will have a wealth of new hosts that have lost any natural immunity they may have had before the pandemic. SARS-CoV-2 was so effective in its spread because it seems that very few if any humans had built-in immunity to the virus. The common viruses will experience aggressive spread by the same model. In the next couple of years, we will likely experience many more deaths relating to the flu, respiratory syncytial virus, and others than we are used to.
Australia is in the midst of its post-pandemic viral re-emergence at this very moment. As the United States continues to have record Covid-19 cases, Australia controlled their Covid-19 outbreak with relative ease, as they never surpassed more than a few hundred cases per day. With Covid-19 cases on the floor, the country has spent the past several weeks rolling back public health restrictions. December, which is outside the typical flu season for the southern hemisphere nation, saw rates of flu six times higher than in the summer, when cases are typically at their peak. If other viruses and countries follow this trend, the year following Covid-19 may not be as relieving as we hoped.
Ultimately, these viruses are endemic. They are always around us and infecting us. After Covid-19 restrictions hit, they went into a sort of dormant state, waiting for new hosts. New hosts will emerge with lowered pathogenic resistance when restrictions end, and these viruses will take advantage.
This is likely what will happen with Covid-19 as well. It’s highly improbable that a virus that caused the magnitude of infection that Covid-19 did could be wiped from the planet. After vaccines and public health efforts eventually control the virus’s spread, there will be annual resurgences of Covid-19 around the world as we see with the flu. We will take new Covid-19 vaccines every year or two alongside our flu vaccines, some will die as with the flu, but life will go on.
The trick is to limit these deaths and illnesses as much as possible and research new ways of controlling viruses so that future generations don’t have to deal with endemic diseases to the same degree.