Seasonal Flu Nearly Eradicated During Pandemic, Despite Rising COVID-19 Cases

Despite the rising number of COVID-19 cases reported across the globe, rates of influenza have virtually flatlined across the Northern Hemisphere, leading many doctors and researchers to wonder how this could be replicated in non-pandemic times.

Many experts believe that measures used to protect against transmission of COVID-19, such as social distancing and wearing masks, have likely contributed greatly to driving down rates of the seasonal flu. In contrast, the rate of COVID-19 and COVID-19-related deaths are rising despite the use of these measures. Ultimately, many specialists agree the apparent inconsistent efficacy of COVID-19 protective measures may be due to the increased transmissibility and highly infectious nature of SARS-CoV-2 compared with some influenza strains.

Prominent health authorities also suggest that the widespread nature of the novel COVID-19 coronavirus, SARS-CoV-2, may be increasing overall immunity against other viruses, effectively “blocking” the seasonal flu. A 2020 study in the Journal of Medical Virology found that out of 8,990 people in New York who tested positive for SARS-CoV-2, there was a lower likelihood of these people to carry common viruses like the flu virus. The theories developed by this research are only hypothetical, however, and require further study to determine if SARS-CoV-2 itself could be protective against seasonal influenza.

According to a story reported in the Wall Street Journal, there were approximately 800,000 flu patients this time last year in Japan, while only 1,000 flu patients have been seen in Japan in the second week of January 2021. And in England, there have been no new hospitalizations for the flu the first week of 2021, a stark contrast to years prior where several thousand people in the U.K. receive hospital or intensive care for influenza in early January.

In a story published in The Jerusalem Post, a large medical health body reported zero cases of influenza in Israel as of mid-January. The novel coronavirus responsible for COVID-19, however, has continued to spread in the country, with more than 8,000 new cases reported Thursday. Similar reports of lower influenza but rising COVID-19 cases have been made in Canada.

In addition to handwashing and mask-wearing, the onset of the pandemic made clear in the minds of many the importance of preventative measures against the flu. The progressive severity of the COVID-19 pandemic among the public consciousness may have also driven higher rates of flu vaccinations, for instance, causing the number of influenza cases to drop dramatically. Over 80% of senior citizens in England, for instance, received the flu shot this season, representing a 10% higher vaccination rate compared with this time last year.

Some health experts fear that the flu may rev back up at a higher rate than previous years once public-health measures against COVID-19 are lifted. A theory suggests that the overall population may have reduced immunity to the flu due to a lack of exposure to influenza viruses. Despite this fear, it is likely influenza viruses will continue to emerge and infect people beyond the current coronavirus pandemic.

To ebb this potential tide, many doctors and scientists indicate that people, especially vulnerable populations, should stick to mask-wearing and routine hand-sanitizing during future flu seasons. The annual flu shot also serves as an important preventative measure against influenza and arguably the best strategy compared with the use of masks. But the combination of the two measures, along with minimizing exposure to those infected, may further improve protection and decrease future rates of infections.