Oregon’s flu season one of the worst in the past decade

Seasonal flu is causing a second peak of illness and hospitalizations in Oregon this month, in what may end up being the worst flu season in the past decade.

That’s part of a national trend. The Centers for Disease Control and Prevention is classifying this flu season as high severity overall for all age groups for the first time since 2017-2018.

That means flu is responsible for a higher-than-usual percentage of doctors visits, hospitalizations and deaths so far this season.

Flu can cause previously healthy people to become extraordinarily sick, according to Dr. Wendy Hasson, medical director of the pediatric ICU at Randall Children’s Hospital at Legacy Emanuel in Portland.

Hasson said that during her shifts this month, she’s treated several children who were critically ill due to the flu “that I have had to put on a ventilator, and on heart support, and sit bedside to manage them moment-to-moment.”

In Oregon, the flu season started out normally. Transmission appeared to peak, as it often does, in late December.

Public health officials use the percentage of flu tests ordered by hospitals and doctors that come back positive as an indicator of how widespread a virus is in the community.

The week of Christmas 2024, 31.5% of Oregonians tested for the flu got a positive result back — a high percentage indicating lots of community transmission.

By mid-January, that positivity rate had fallen to about 18%. Hospitalizations were falling too. It looked like the beginning of the end for the flu season.

Then something unusual happened, said Dr. Paul Cieslak, medical director for communicable diseases at the Oregon Health Authority. The test positivity rate for influenza started to climb again, along with hospitalizations. Last week, 21% of flu tests came back positive. The week before, the percentage was even higher. Both peaks have been due to Influenza A.

State health officials don’t have the capacity to track flu hospitalizations statewide, so the Portland metro area serves as a proxy for how severe the season is. Since the start of flu season in October, OHA has reported 1,345 influenza hospitalizations in Clackamas, Multnomah and Washington counties. That number appears to be on par with what the state reported in the 2017-2018 season, a notably bad year for flu.

The hospitalization rate is the highest for people 65 years and older by far. That population accounts for about half of the patients hospitalized from the flu in the Portland metro area.

“This is not a quiet year for flu. I think it’s gonna be one of our worst,” Cieslak said. “I would definitely get vaccinated if you haven’t already.”

The flu shot: not perfect, but effective

The CDC recommends the flu shot annually for everyone 6 months and older.

Despite that, less than half of Oregonians typically get their annual flu shot. And the percentage that does has been falling. Five years ago, 36.5% of Oregonians had their flu shot by late February. To date this flu season, 29% of Oregonians have been vaccinated.

To Hasson, who treats people for flu complications in the ICU every year, the flu shot is the single vaccine she would recommend above all others.

Yet the shot has a reputation for not working well.

“This isn’t our best vaccine,” when compared to shots like the measles vaccine, which prevent almost all cases of infection, Cieslak said.

“In a typical year, flu vaccine is 40% to 50% effective against having to go to the doctor with the flu. It’s better, maybe 60%, in keeping you out of the hospital, but there are always some cases that manage to get through despite vaccination,” he said.

What that means is that many people who get the flu shot will get the virus anyway, giving the shot bad word of mouth and contributing to people skipping it.

The problem, according to Hasson, is that influenza is a more serious virus that many people realize. It can affect the entire body, attacking the heart, lungs, brain and kidneys.

In cases in which people felt miserable and view the shot as not having worked, it may have provided some protection against even worse outcomes.

In 2019, with funding from the CDC, researchers looked more closely at the most serious outcomes of the flu in children: patients who were sick enough to need a ventilator and those who died from the virus. That study found that even in a year when the flu shot was not a great match for the strains of the virus that were circulating, it reduced the worst outcomes for kids by about 75%.

To date, OHA has reported 22 children 4 years and under hospitalized due to the flu. Fifty-two children between 5 and 17 years old have been hospitalized. In December, OHA reported two pediatric deaths due to flu.

Hasson said that pediatric deaths from flu are rare. But the influenza virus is much more likely than others that have been in the news — RSV, COVID-19 or norovirus — to cause extended hospitalizations for children. Some of those extended battles with the virus can cause long-term harm, leaving kids in need of ongoing oxygen support or unable to participate in sports.

This year, the ICU at Randall Children’s Hospital has treated higher-than-usual numbers of children with complex cases of influenza, she said. Those include cases in which a child, weakened by the flu virus, develops a secondary bacterial infection or abscess.

Hasson said the “overwhelming majority” of children who need prolonged ICU stays have not been vaccinated against the flu.

Along with getting the vaccine, another step health officials recommend is proactively testing for the virus. For the first time this year, there’s an at-home test for the flu available over the counter at pharmacies: the single-swab tests for influenzas A and B and COVID-19. Antiviral treatments for flu work best if they are started one or two days after symptoms begin.

Changes at the federal level

The severe flu season also comes in the midst of policy changes on the federal level that trouble Hasson.

Last week, NPR and STAT reported that the CDC pulled the plug on a paid ad campaign for the flu vaccine, called Wild to Mild, shortly after Robert F. Kennedy Jr. was appointed as secretary of the U.S. Department of Health and Human Services. A spokesperson for HHS told NPR that officials inside the CDC were “falsifying and misrepresenting guidance they receive.”

The goal of the CDC’s flu campaign was to “reset public expectations around what a flu vaccine can do in the event it does not entirely prevent illness,” according to a press release. That message, the agency said, helped consumers and motivated some to get the shot.

Earlier this month, Kennedy told senators he would not change the childhood vaccination schedule. Later, according to the Associated Press, he told staffers at HHS that childhood vaccines would be investigated to see if they contribute to chronic illnesses.

Hasson is concerned that in years to come more parents will be swayed by Kennedy’s rhetoric. He has previously cast doubt on the safety of routine childhood vaccines, which have been found under numerous studies to save lives and very rarely have serious side effects.

“I am really worried that I am looking down the barrel of seeing the number of children that we’re treating for vaccine preventable illnesses just go up and up,” Hasson said.