Outbreaks of COVID-19, flu in fall will challenge public health
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* Mark Barna

![Figure1](http://www.thenationshealth.org/http://www.thenationshealth.org/content/nathealth/50/7/4.2/F1.medium.gif)

[Figure1](http://www.thenationshealth.org/content/50/7/4.2/F1)

Courtesy BackyardProduction, iStockphoto

The COVID-19 pandemic in the U.S. spiraled out of control this summer, with record infections in multiple states. Fall and winter may be worse for public health, according to Robert Redfield, director of the Centers for Disease Control and Prevention.

“I do think that fall and winter of 2020 and 2021 are probably going to be the most difficult times we experience in American public health,” Redfield said during a July 16 interview with the *Journal of the American Medical Association*. “Keeping the health care system from being overstretched is going to be really important, and the degree to which we do that will define how well we get through the fall and winter.”

Because COVID-19 is a novel coronavirus, scientists do not know with certainty how it will respond during cooler seasonal temperatures in the U.S. However, COVID-19 is one in a family of coronaviruses, and during previous outbreaks cooler weather increased infections.

Further knowledge of how the virus will react may be gleaned by examining its behavior in the Southern Hemisphere, where winter began in June.

A study published in June in *Transboundary and Emerging Diseases* looked at COVID-19 infection rates in Sydney, Australia, in March, which is autumn there. COVID-19 cases notably increased as temperatures and humidity dropped. A 1% reduction in relative humidity was associated with a 6% increase of virus cases.

“COVID-19 is likely to be a seasonal disease that recurs in periods of lower humidity,” Michael Ward, PhD, an epidemiologist at the University of Sydney’s School of Veterinary Science and lead author of the study, said in a news release.

A major challenge is that COVID-19 symptoms overlap with influenza and other respiratory infections, said Michael Baker, MBChB, FNZCPHM, FRACMA, DComH, a global public health professor at New Zealand’s University of Otago-Wellington.

“People will present with respiratory infections and use scarce COVID-19 testing resources when they in fact have other infections,” Baker told *The Nation’s Health*. “These other respiratory infections will also cause serious, sometimes life-threatening infections, and put pressure on hospital facilities that may already be overwhelmed with COVID-19 cases.”

New Zealand has successfully stanched COVID-19; deep into winter in mid-July, the country had no coronavirus cases. But public health workers are still doing double duty: Testing for COVID-19 continues alongside flu vaccines and addressing other respiratory infections, Baker said.

Meanwhile, U.S. health departments are organizing how to administer seasonal flu vaccines safely while workers struggle to contain COVID-19, the National Association of County and City Health Officials said in June. NACCHO recommended that health departments adopt telehealth services for immunization education and counseling, and offer drive-thru vaccination options.

For information on this season’s flu vaccine, visit [www.cdc.gov/flu](http://www.cdc.gov/flu).

*   Copyright The Nation’s Health, American Public Health Association