Anticipating the Convergence of COVID-19 & Seasonal Influenza

As we enter the month of August, COVID-19 is raging across much of the U.S. Sunbelt, a proportion of children are returning to in-person learning in K-12 classrooms, and young adults are traveling, often across state borders, to begin or resume college or university studies. The next couple of months will be a particularly precarious period in terms of the trajectory of the COVID-19 pandemic in our country. Just in time for an impending flu season.

Seasonal influenza, as we know, can cause considerable morbidity, mortality, and hospital utilization. The burden is greatest for the elderly and those who have underlying health conditions, incidentally the same demographic at highest risk for severe COVID-19 disease. It’s not a great leap to imagine that the convergence of pandemic COVID-19 with seasonal influenza could be messy. Even a moderate cold and flu season could be expected to amplify the challenges provoked by the COVID-19 pandemic. Cold, flu, and COVID-19 symptoms often overlap, making diagnosis difficult and test dependent. More people with respiratory symptoms seeking medical attention in practice offices, urgent cares, and hospitals will inevitably increase demand for COVID-19 testing, thereby straining an already burdened infrastructure. Severe cases of influenza requiring hospitalization may contribute to the overwhelming of acute care centers in COVID-19 hotspots. Personal protective equipment supplies will dwindle at faster rates and may become increasingly difficult to obtain, once again.

More optimistically, it is possible that the dramatic behavioral changes adopted by Americans to curb the spread of COVID-19 will have the desirable latent effect of (perhaps substantially) minimizing flu transmission. Indeed, a limited study published in the venerable medical journal The Lancet, in April, suggested that COVID-19 mitigation measures implemented in Hong Kong in the late winter led to a rapid decline in flu activity. Similarly, flu cases in the United States plummeted shortly after COVID-19 was declared an emergency of international concern, abruptly ending what had been a relatively severe flu season. On the other end of the spectrum, influenza and COVID-19 co-infection could occur with relative frequency and, as shown by a retrospective study printed in the Journal of Medical Virology in June, co-infection could worsen expected clinical outcomes for the individual diseases, resulting in increased mortality and substantial societal burden. We simply do not know.

Fortunately, we have a critical tool at our disposal as we prepare for the prospect of concurrent pandemic COVID-19 and epidemic influenza: this year especially, every eligible American should receive a flu vaccination. Flu vaccination is safe, moderately effective, and an awful lot better than nothing. This year, Deerfield residents can expect to receive even more encouragement than usual to accept an annual flu vaccine. The Deerfield team is collaborating with both MAHEC and SONA Pharmacy to ensure that everyone at Deerfield, residents and staff alike, have ample opportunity to receive flu vaccination, conveniently offered right here on our campus (with every infection control precaution in place in a wide open and well-ventilated space) and delivered with optimal timing in the early fall.