As the winter season officially begins, flu cases are climbing across the United States, and health authorities are warning that the worst is yet to come.
In a presentation on YouTube about the current respiratory virus season, Mandy K. Cohen, MD, MPH, director of the Centers for Disease Prevention and Control (CDC), cautioned that respiratory illnesses are expected to keep rising in the weeks ahead, with the flu being “the most accelerated.” (COVID-19 is also increasing, but RSV appears to be slowing a bit as it most likely has peaked for the season.)
Latest CDC tracking indicates that flu cases and related hospitalizations are trending upward, and deaths from flu also inching up slightly.
The CDC Influenza Surveillance Report on December 22 shows the highest levels of flu activity in the southeast, south-central, and West Coast areas of the country, but the illness is spreading in all regions of the United States.
With more people traveling and gathering with family and friends for the holidays, Robert H. Hopkins Jr., MD, medical director of the National Foundation for Infectious Diseases (NFID), anticipates we will at least see a few more weeks of rates continuing to climb.
“We’re seeing a very common pattern this year,” says Dr. Hopkins. “Influenza is a respiratory virus that tends to circulate among people who are in crowded conditions, and as the weather gets colder, more people are crowded together indoors. Also, influenza tends to pass easily among schoolchildren and then they pass it on to the adult population.”
How Bad Will This Flu Season Be?
So far this season, the CDC estimates that there have been 3.7 to 7.4 million flu illnesses, 1.4 to 3.5 million flu medical visits, 38,000 to 80,000 flu hospitalizations. and 2,300 to 6,800 flu deaths.
For the entire U.S. flu season last year, the CDC calculated that there were about 31 million people sick with flu, 14 million visits to a healthcare provider for flu, 360,000 hospitalizations for flu, and 21,000 flu deaths.
Last year’s flu season in the U.S. was characterized as highly severe, particularly among children and adolescents, the CDC notes. This was in stark contrast to the first years of the COVID-19 pandemic, when flu rates plummeted as many people took more precautions against respiratory viruses. Then, as COVID slowed and people dropped their guard, a population with lower flu immunity from prior virus exposure experienced an influenza spike.
Whether this year will be as bad is still a question.
“They had a particularly difficult influenza season in Australia this year in the Southern Hemisphere [which can act as an indication of what’s to come for our flu season],” says Hopkins. “That concerns me that we may be looking at a severe season here, but it’s really challenging to predict.”
The CDC is not seeing anything out of the ordinary so far. “We know this time of year, we’re going to see more respiratory illnesses,” Dr. Cohen said in her presentation.
Vaccinations Provide Proven Protection Against Flu
No matter the trajectory of flu illnesses in the weeks to come, Hopkins stresses that the available flu vaccination should provide strong protection against serious illness. A CDC study from earlier this year found that the vaccine reduced the risk for influenza-associated hospitalizations by 52 percent in the Southern Hemisphere during their past flu season.
Annual vaccination is recommended for people of all ages, including children 6 months and older, and adults over 65 are urged to get a higher dose or adjuvanted flu vaccine, per the CDC. The National Institute on Aging stresses that flu is more dangerous in older adults as peoples’ immune systems weaken with age, increasing the risk of picking up a secondary infection such as pneumonia.
Although vaccination provides a powerful defense against influenza, Hopkins is concerned that flu vaccination rates are way down this season compared to last, with about 7 million fewer doses being administered to adults.
“Although it does take 10 days to two weeks to develop full immunity from the vaccine, I’d encourage anyone who has not yet been vaccinated to get vaccinated,” he says. “If you haven’t had it, better to get vaccinated now and get protected through the rest of the season than to take a chance. I really encourage people to do everything they can to protect themselves and their families.”