This year’s flu season is coming to a close, and it will be remembered as a challenging one. The seasonal flu vaccine, which is formulated based on experts’ predictions about which influenza strains were likely to circulate that year, wasn’t very effective. One of the strains included in this year’s batch mutated just enough that the vaccine didn’t protect against it, meaning that even people who got a flu shot might still get sick.
The good news is that even in an off year like this one, the flu vaccine keeps you from getting as sick if you do catch the bug. In fact, you may not even realize you had the flu and decide to go to work. This might not be a problem for someone who works with other healthy, mostly-immunized adults, but for health care workers caring for already sick or weakened patients, the risk of spreading the flu is a real problem.
The Centers for Disease Control and Prevention (CDC) recommends health care workers with flu-like respiratory symptoms and a fever stay home from work until at least 24 hours after the fever is gone. The CDC does say it’s okay for someone to go to work at the hospital if they have respiratory symptoms and no fever, however, provided they wear a face mask around patients.
During last year’s flu season, which was equally challenging, there was one suspected case of a patient at the University of Chicago Medicine getting the flu from a health care worker who had respiratory symptoms but no fever, so the infection control team decided to implement a temporary policy of mandatory influenza testing for all such employees. They published a paper in the journal Clinical Infectious Diseases about the testing program, and the results pose a bit of a quandary for the next flu season.
Over a two-month span, 449 workers with respiratory symptoms were tested; 41 had some strain of influenza, but only 21 of those reported a history of fever or had a fever when they were tested. That means nearly half of the health care workers who actually had the flu didn’t have a fever, the CDC’s key symptom for asking them to take a sick day. And half of the workers with the flu had been vaccinated too.
“That was surprising to us, and certainly calls into question the policy,” said Jessica Ridgway, MD, assistant professor of medicine and lead author on the study. “The issue is that if you said anyone who has any respiratory symptoms whatsoever can’t come to work, we wouldn’t have anyone to staff the hospital. It’s so common to get a mild, viral, upper respiratory infection, which is why instead of saying no one can come to work with respiratory symptoms, we decided to test for the flu.”
Ridgway said the testing program was expensive, about $200 per test, and labor-intensive too. Staff were on call 24/7 for testing at several locations in the hospital. The system relied on self-reporting, but all staff and managers knew the policy and would nudge any sickly co-workers to get tested.
“There actually were some employees who would tell us, ‘Dr. So-and-So is coughing and hasn’t been tested,’” Ridgway said. “So we would call them up and say, ‘Hey, how are you feeling? Do you want to come get tested?’ It’s hard to hide it if you’re sick.”
She and her colleagues worried about the implication that getting the flu vaccine might make it more likely for a health care worker to spread the flu to patients because they don’t have a fever and feel well enough to go to work.
“It maybe undermines the argument for mandatory vaccination a little bit,” she said, but quickly dismissed it.
“You definitely should get vaccinated every year,” she said.