Flu season may worsen COVID testing delays
Come fall, the rise of influenza and other seasonal respiratory infections could exacerbate already staggering delays in coronavirus testing, making it easier for the virus to spread unnoticed, experts said.
In typical years, doctors often don’t test for the flu, simply assuming that patients with coughs, fevers and fatigue during the winter months probably have the highly infectious virus. But this year, with the coronavirus bringing similar symptoms, doctors will need to test for both viruses to diagnose their patients — further straining supply shortages in an already overwhelmed testing system.
A handful of manufacturers have begun making tests that can screen for several pathogens at once. But these combo tests are expensive and likely will make up only a fraction of the market. Some researchers are trying to make their own multivirus tests as well, but they almost certainly won’t fill in the gaps.
“The flu season is a bit of a ticking time bomb,” said Amanda Harrington, medical director of microbiology at Loyola University Medical Center. “We are all waiting and trying to prepare as best we can.”
Flu viruses and coronaviruses differ in many ways, including how they spread, how long they linger in the body and the groups they affect most severely. The Food and Drug Administration has approved antivirals and vaccines for the flu but not for the coronavirus, which has killed about 800,000 people worldwide in less than a year.
Being infected with one virus doesn’t preclude contracting the other. And researchers also haven’t learned how risky it is for a person to harbor both viruses at the same time.
Those differences make it essential to look at the two pathogens separately, as well as rule out other common wintry infections such as respiratory syncytial virus, which hits the very young and very old especially hard.
But testing for individual viruses poses many challenges for doctors and laboratory workers already fighting their way through supply shortages. Several of these tests use similar machines and chemicals, and require handling and processing by trained personnel.
What’s more, many flu and RSV tests vanished from the market this spring as the companies that make them rapidly pivoted to address the coronavirus.
Late summer is typically when laboratories start stockpiling flu tests, RSV tests, and flu-RSV combo tests in anticipation of the fall surge, said Susan Butler-Wu, clinical microbiology lab director with the University of Southern California’s Keck School of Medicine, whose lab buys thousands of these tests every winter. But the supply chain shake-up has left shelves empty just weeks before one of the busiest times of the year.
“Many people are legitimately concerned about the winter because we’re not able to squirrel away our nuts right now,” Butler-Wu said. “Every lab is fighting to get what they need for their system.”