While COVID-19 raged across the U.S. during the winter as health experts feared, the threat of a bad flu season at the same time – a twindemic, it was being called – quietly disappeared.
This was particularly stark at the UC Davis Medical Center. Although a higher percentage of patients were tested for influenza this season, there were no positive flu tests for any patient admitted to the hospital. None.
Historically, about 5% of the Molecular Pathology Lab flu tests come back positive, and the hospital averages 200-plus patients with influenza each season.
There was, in essence, no flu season. The measures used to at least slow COVID-19 appear to have been even more effective against the flu everywhere in the country.
The Centers for Disease Control and Prevention (CDC) said throughout the entire U.S., there were only 165 patients hospitalized between Oct. 1, 2020 and Feb. 6, 2021 because of lab-confirmed influenza illness. This is the fewest the CDC has seen since regular data collection began in 2005, it says on its flu tracker site.
“If you combine the remarkably low influenza numbers with the continuing and emerging COVID-19 masking studies, the conclusion is clear,” said Daniel Colby, a UC Davis Health assistant professor of emergency medicine. “We should be masking, social distancing and getting vaccinated for COVID as much as possible.”
— Daniel Colby
Colby, a clinical operations leader in the Department of Emergency Medicine, said they tested many more emergency patients this season because UC Davis Health uses a groundbreaking combined COVID/Flu rapid test. The number of patients who tested positive for the flu was about one-fifth of any normal year, and none needed hospitalization.
Natascha Tuznik, UC Davis assistant clinical professor of infectious diseases, said the medical center saw very few cases of other common respiratory diseases compared with previous years – beyond the surge of COVID-19. And the molecular lab reported zero hospital admissions for respiratory syncytial virus (RSV), which generally causes cold-like symptoms but can be serious for infants and older adults. In normal years, the hospital averages more than 200 RSV patients.
“It shows how much help masking and social distancing can be in preventing the spread of disease,” Tuznik said. “Unfortunately, COVID-19 is more easily transmitted and some people did not do the best job possible with masks and distancing during the holidays and the winter.”
It could have been much worse for hospitals and patients
Still, Colby said UC Davis and hospitals across the country at least dodged one bullet while they battled the sometimes overwhelming cases of COVID-19 from the holiday and winter surges.
— Daniel Colby
“If any of us had a typical flu season on top of that, it would have been disastrous,” he said.
The UC Davis emergency department and medical center attacked that possibility as much as possible with the rapid combined tests and by vaccinating everyone who came into the emergency department who consented.
“We saw a lot more people getting the flu vaccine this year, not just in our hospital but throughout the community,” Colby said. “That shows how important vaccines are to staying healthy.”
Flu season typically peaks by mid-February, so Colby and Tuznik are sighing a small bit of relief, but they said the medical center is still extremely watchful. And they encourage people to continue to get their influenza shots when the new flu season starts in the fall.
“There are lessons from this,” Colby said. “All indications are that masking, social distancing and vaccinations work. I hope public health officials and our community continue to take those into account as we fight COVID-19 and when the next flu season comes around.”