We wish we were starting 2026 on a lighter note, but flu season has other plans.

As we said goodbye to 2025 we saw a sharp rise in serious flu cases, including more hospitalizations than we typically expect in late December. If it feels like “everyone is sick right now,” that’s not just your group chat talking.

The numbers change each day, but as of January 6, 2025, CDC and public health officials estimated about 11 million flu illnesses, ~120,000 hospitalizations, and ~5,000 deaths so far. That’s nearly double the last season’s numbers at this point (~5.3 million illnesses and ~63,000 hospitalizations).

Let’s unpack what’s going on.

Generally, we see a surge in flu cases at year’s end.

A few factors tend to collide all at once.

First, holiday timing. Travel, crowded gatherings, and indoor celebrations make it easier for viruses to spread—especially when people are tired, stressed, or brushing off early symptoms.

Second, delayed vaccination. Many people plan to get a flu shot “later” and never quite get around to it. By December, immunity levels across communities can be lower than ideal.

Third, post-pandemic behavior shifts. Masking, staying home when sick, and cautious social habits have eased. That’s understandable, but it also gives respiratory viruses more room to move.

Why is it worse this year?

Much of the current surge is due to the “subclade K” subvariant, which is highly transmissible and now accounts for the majority of cases. This variant wasn’t as common when the vaccine was designed, which may help explain faster spread and higher infection rates.

Vaccination rates are lower than ideal. Coverage this season has lagged prior years; for example, only about 42% of U.S. children had received a flu shot by mid-December. That’s down from 53% at the same point in 2019–20 (pre-COVID).

Population immunity may be lower overall. Because flu activity was relatively low during some recent seasons when people were masking and staying home more (COVID era), fewer people have recent immunity from infection. That can leave larger swaths of the population susceptible now.

Where is flu hitting hardest right now?

The CDC, along with regional health departments track something called ILI. It stands for “influenza like illness,” and it means that the cases tracked may include other viral infections like RSV and COVID but is not likely to include patients with suffering from bad colds. Flu activity tends to rise unevenly across the country, with large week-to-week swings. But the dramatic and broad increase in cases during the last three weeks is breaking records in all but a few states, like Montana, South Dakota, and Vermont.

Is this year’s flu vaccine less effective?

This is a common question, and an important one to understand.

So far, there’s no indication that this season’s flu vaccine is unusually weak or mismatched. Flu vaccine compositions are set months in advance (around February for the Northern Hemisphere). That means as flu season is ending one year, experts are selecting the strains to target with the next season’s vaccine. Viruses being viruses, those strains always mutate in some way between February and September when the vaccine is rolled out. That means there will always be strains that get past the vaccine, but the vaccine will protect against some strains completely and will ensure a milder infection if you’re exposed to a mutated strain. A vaccine will always prevent or mitigate symptoms.

This season’s dramatic increase in severe flu cases can only be explained by lower vaccination rates and lower immunity overall, not by relative vaccine efficacy. This is true even though many people cite rumors of lower efficacy as their reason for not getting a flu shot.

All flu vaccines train your body to fight the flu. The vaccine will lower the severity and duration of the flu and will likely keep you out of the hospital. That matters, especially for older adults, people with chronic conditions, pregnant individuals, and young children.

Is it too late to get a flu shot?

No. It’s absolutely not too late.

Flu activity begins in earnest in November and peaks again in January or February. Getting vaccinated now can still protect you for the rest of the season, and help reduce spread to others.

If you’re unsure whether it makes sense for you, this is a great moment to talk with a medical professional. Our Amaze team can help you decide what’s right for your health, your risk level, and your household.

A Quick Word on Vaccine Hesitancy

Vaccine hesitancy has risen in recent years, for many reasons. We won’t get political here, but we will say this: the most reliable guidance comes from trusted medical professionals who know your health history, not headlines or social media. Also, flu shots are not particularly controversial. Everyone six months and older is eligible for the flu vaccine unless they have a specified medical condition, such as an allergy to its ingredients or a previous severe reaction to the shot.

Outside of squeezing in a late vaccine, you know the drill: Wash your hands religiously (warm water, at least 20 seconds) and disinfect common areas. Most important, do not go to work! Powering through when you begin to feel rotten always does more harm than good. You are quite likely to infect your colleagues and lengthen the duration of your own virus, which thrives on activity.

If someone in the family has the flu take every necessary precaution so your family isn’t serially suffering through spring. Avoid sharing pens, papers, clothes, towels, sheets, blankets, food or eating utensils unless they have been cleaned between uses. Disinfect doorknobs, switches, handles, computers, telephones, toys, and other surfaces that are commonly touched around the home or workplace. Wash dishes in the dishwasher or by hand using very hot water and soap. Wash clothes as you normally would, using detergent and very hot water. Wear disposable gloves when in contact with or cleaning up anything used by the person who is ill. Wear a mask, for your own protection, when checking in.