The United States is seeing a second peak in flu cases this season. After doctor’s office visits for flu dipped early this year, they jumped past the previous season peak at the end of last month, with a 30% test positivity rate — and there are still months to go.
The US Centers for Disease Control and Prevention estimates that there have been at least 20 million cases and 11,000 deaths from flu so far this season. Hospitalizations are rising too, with an estimated 38,255 hospitalizations from flu last week alone. It’s not the only illness spreading, either: Wastewater testing also shows high levels of the virus that causes Covid-19 across the country — well above levels seen at the start of winter.
But there are some new tools to help this respiratory virus season: over-the-counter tests that can identify whether an illness is Covid-19 or influenza.
The tests are available for purchase at most pharmacies or online and allow patients to learn what may be making them sick without needing to make an appointment at a clinic or wait in line.
The tests won’t check for every respiratory virus, but they mark the first time the public can test for flu at home. The tests use self-collected nasal swabs, with results ready within 15 to 30 minutes, depending on the type of test.
Several companies have received emergency use authorization from the US Food and Drug Administration and brought combination tests to market. One test, Healgen, has received authorization for marketing outside of emergency use.
Most use rapid antigen technology, meaning the test can identify a particular component of the virus and then alert the user that the component is present.
Another home test, Pfizer’s Lucira, works through RT-LAMP technology, which detects the genetic material of the virus and amplifies it for identification.
What to do if you test positive for flu
If you have symptoms but test negative for flu or Covid, you could have a different infection, have tested too early, or could be getting a false positive result. CDC guidance says to take added precautions and call a health provider for care.
Experts say people who test positive for Covid or flu should isolate themselves as much as possible to protect loved ones and get in contact with their doctor, especially if they have underlying health conditions.
Dr. Sarah Nosal, a primary care physician in the Bronx, New York, stresses the importance of isolation to stop the spread of illness.
“Because I’m a family doc, I’m usually taking care of all those people who live in that same house or in the community with that individual. … It’s really about helping both prevent other exposures and the basics of caring for you,” she said.
The home tests may also help patients get treatment faster.
Dr. William Schaffner, an infectious disease expert at Vanderbilt University Medical Center, says his emergency department is currently full of people with respiratory infections, the majority of whom are sick with the flu.
“What we say is ‘oh, I’ll get better in the morning’ or ‘I don’t want to bother the doctor.’ And so, we postpone the contact with the health care system,” Schaffner said. “And of course, when we do contact, then it’s two days later, and the treatment is going to be somewhat less effective. So, if the testing were widely available … then that might motivate patients to contact their providers earlier.”
The differentiation between flu and Covid can also be critical when determining treatment and managing symptom expectations. Covid-19 can cause more serious illness in particular cases, according to the CDC. Patients who test positive for Covid could also be at risk of long Covid.
Both viruses also have different antiviral treatment options. Although most people will get better in a few days without drugs, antiviral medications like Tamiflu and Paxlovid are more effective when given within the first two days of symptoms, according to the CDC.
For new tests, ‘adoption takes a while’
Mara Aspinall, a professor of practice in biomedical diagnostics at Arizona State University, says she has seen these combo tests in every pharmacy she has entered this season.
“This is the first year that you have been able to get any sort of a flu test fully at home and … adoption takes a while,” she said.
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Purchases of the tests have increased in recent months, according to Michael Mina, chief scientific officer of the telehealth company eMed and an expert in the epidemiology, immunology and spread of infectious disease.
But with flu cases continuing to rise, experts are concerned about whether people will use them.
This is in part because the over-the-counter Covid-flu tests are not covered by insurance. Walgreens sells its lowest-cost brand for $30 per two-pack, and prices are similar at other pharmacies.
“I think that’s a big barrier right now: People don’t really want to pay for it,” said Mina,
“Now, I just hope that we continue to see barriers to health care come down as the tools that would normally be used in a health care provider in a setting … you can use while sitting in bed,” he said.