Covid-19 precautions thwart the flu

“We are seeing very low flu levels so far,” said Daniel Jernigan, director of the flu division at the Centers for Disease Control and Prevention. Between wearing a mask, socializing, and measures like shutting down bars, “all of these things affect flu,” he said.

Clinical laboratories tested 22,474 patient samples, mostly nasal swabs, for influenza during the week ending December 5, and only 40, or 0.2%, came back positive, according to data from the CDC. In the same period last year, more than 11% of the more than 41,000 samples were positive.

The number of positive flu samples in U.S. public health labs is also lower than in recent years, according to CDC data. These labs are currently processing more patient samples than in previous years due to the explosion of tests on Covid-19.

A less severe flu season is a welcome development during a pandemic that got out of hand, health authorities said earlier this year, who feared a potentially dangerous clash between the coronavirus and seasonal flu would engulf doctors’ offices and the emergency room. Doctors and public health officials urged Americans to get flu shots, and labs have moved to determine whether feverish, coughing patients have the flu or Covid-19.

In the Southern Hemisphere, Covid-19 precautions practically eradicated the flu this year, offering hope for a lighter flu season in the US and Europe. It was not certain whether the season would follow in the US, but the spread of influenza in the country appears to be following a similar pattern.

Flu-related hospital admissions have also gone down. There have not been enough laboratory-confirmed hospitalizations to meet the CDC’s threshold to start reporting such data, said Dr. Jernigan. The threshold is 300 hospital admissions. Normally, the US would have passed that point by now.

“There are many available databases that we have access to, and right now they all tell us the same story,” said Jeffrey Kahn, chief of infectious diseases at the Children’s Health hospital system in Dallas. “There is very little activity.”

A lower rate of flu-related hospital admissions is good news for hospitals, say public health authorities, many of which are stretched with Covid-19 patients.

“If you can get more beds in your hospital because fewer people get sick with the flu, then that helps you,” said Imelda Dacones, president and chief executive officer of the Northwest Permanent Medical Group. A lighter flu season also means fewer doctor visits, so doctors can save resources for more serious illnesses or other medical problems, said Dr. Dacones.

Other seasonal viruses have also taken a hit this year, public health authorities say. In September through November 2019, Children’s Health saw 892 cases of RSV, a common respiratory virus that usually infects children. During the same period in 2020, the system reported one case.

Flu cases over the same period have also decreased, from 722 cases in 2019 to four in 2020.

“That just amazes me,” added Dr. Kahn adds. “The highest priority at the moment is to get this pandemic under control. In doing that, we also have a profound effect on some of these other viruses. The lower rates are another sign that Covid-19 mitigation measures are also helping to reduce Covid-19, Dr. Kahn says.

Flu season is still in its early stages, and the number of cases may change in the coming months, health experts say, especially as people start dropping precautions. Health authorities are still urging people to get flu shots this year. The last time the numbers were relatively low at this point in the year was during the 2011-12 flu season, which had an increase in the number of cases in late January but remained generally mild, said Dr. Jernigan.

According to the CDC, about 49% of adults in the US had been vaccinated against the flu in early November, slightly more than the 44% who received flu shots during the same period a year ago.

“The best we can hope for is that people will be vaccinated, they will continue to comply with the requested measures and therefore the flu will be limited as much as possible for the rest of the season,” said Dr. Jernigan.

—Anthony DeBarros contributed to this article.

Write to Brianna Abbott at [email protected]