A pulmonary and critical care specialist identifies 4 factors that will, in part, determine the severity of the 2020-2021 flu season and that can inform preparation.
In an editorial published in May in Science Advances, Benjamin Singer, MD, assistant professor of pulmonary and critical care and biochemistry and molecular genetics at Northwestern University Feinberg School of Medicine, examined the epidemiology and biology of SARS-CoV2 and influenza to help inform preparation strategies for the upcoming flu season.
He noted that influenza and other respiratory infections represent the eighth leading cause of death in the United States, and among patients hospitalized with community acquired pneumonia, viruses are the most common pathogens. Seasonal flu spawns an annual epidemic in the US with the CDC reporting tens of millions of cases for the 2019-2020 season.
So, what lies ahead as the COIVD-19 pandemic continues and flu season arrives again and how can we use what we know about the behavior of both infections to prepare?
Dr Singer points out that the last human coronavirus epidemic, SARS (SARS-CoV, 2003), was contained through aggressive public health measures before a vaccine could be approved and deployed. Moreover, community transmission of SARS-CoV has not occurred since 2004. It is clear, Singer says, that based on the course of the COVID-19 pandemic to date and timelines for vaccine development and approval, such an abrupt termination of the SARS-CoV2 trajectory is not in our future.
As community transmission of SARS-CoV2 continues and flu season is inevitable, Singer lists 4 factors that, in part, will determine the overall severity of the upcoming respiratory virus season and can inform how we prepare:
Both viruses predominantly spread through respiratory droplets transmitted during close community contact. Social distancing practices adopted to limit COVID-19 transmission also are effective against influenza. If COVID-19 cases begin to spike in the fall,retightening of social distancing measures could help contain early spread of influenza to flatten the case-rate curves for both diseases.
US influenza vaccine efficacy for 2019–2020 was 45%. As COVID-19 vaccine research moves through phase 3 clinical trials, planning to mitigate the overall US burden of respiratory disease should include widespread efforts to increase rates of vaccination against influenza and particularly among older adults and other vulnerable populations with increased susceptibility to both flu and COVID19.
Co-infection with another respiratory pathogen, including influenza, was seen in >20% of COVID-19 positive patients who presented with a respiratory viral syndrome early in the pandemic. Widespread availability of rapid diagnostics for COVID-19 and other respiratory pathogens is essential. Clinicians also may need to modify treatment regimens depending on the concomitant pathogen (eg, oseltamivir for influenza).
The COVID-19 pandemic has highlighted longstanding and destructive disparities in healthcare and healthcare access among African Americans, Latinx and Native Americans, populations overrepresented among COVID-19 cases and deaths.
Public health efforts must target limiting viral transmission, increasing vaccination, deploying rapid diagnostics and expanding other health services for vulnerable populations, including communities of color, the poor and older adults.