The Flu Forecast: Are We Facing A Sickness Storm?

So, are we in for a mild winter, or is the forecast more stormy? In particular, what’s the forecast for “influenza” storms in the coming months? How bad a flu season we will experience is always a bit of a guessing game. But if we look at some of the “tea” leaves currently available, we may be able to discern a potentially stormy flu season ahead. This is of particular concern to older adults, who are among the most vulnerable to severe illness, hospitalization, and even death due to the flu. According to the CDC, 50%-70% of flu-related hospitalizations, and 70-85% of flu-related deaths, occur in people aged 65 and older. Last year’s flu season was among the most severe in over a decade. During the 2024-2025 flu season, there were over 56 million symptomatic cases in the US, and over 770,00 hospitalizations, with the majority (77%) involving older adults. This year, in countries that typically start their flu season before the US, the signs of trouble are evident. For example, already in the UK, flu cases are triple what they were at the same time last year, and flu cases in Tokyo have surged to nearly six times the level they were at this time last year. Why does this portend bad news for the US, and especially for older adults? It has to do with a new strain of the flu that has emerged, and that is mismatched with this year’s vaccine.

The most prevalent strain of the flu currently circulating is called “subclade K.” It is a mutated variant of the H3N2 influenza that we have faced in previous flu seasons, and it tends to cause more severe symptoms, such as high fever, fatigue, and severe body aches. The CDC estimates that about 56% of current flu cases are this variant. The current flu vaccines were developed before the emergence of the subclade K variant. Does that mean you should skip this year’s vaccine because it has not been formulated to directly fight this virus? The answer from experts is that you should definitely still get the flu shot this year. As influenza experts make clear, even if the current vaccines won’t necessarily prevent infection from subclade K, the data from previous seasons with vaccine mismatches show that getting the flu shot will nonetheless mean you’re less likely to become so sick that you require hospitalization. And current data from the UK is showing that despite the mismatch, the vaccines are about 30-40% protective against hospitalizations among adults. 

However, to date, there are worrisome signs that Americans are not heeding the advice to get flu shots this year. Data shows that US pharmacies gave 2 million fewer flu vaccines this October than last year during October. That means that fewer people will be protected, creating more opportunity for the virus to spread and more hospitalizations as a result. Since none of us wants to get sick, it behooves us all to get this year’s flu vaccine if you haven’t already. That is certainly the advice of the American College of Physicians, which advises that adults over age 65 who are not immunocompromised should receive either a high-dose trivalent or a high-dose quadrivalent egg-based influenza vaccine. And if you’re worried about getting the flu as a result of receiving the flu vaccine, try to put that fallacy aside and find out why you’re falling for a myth here.

If these warnings don’t convince you to get a flu shot, perhaps some additional new research will. A new study published in the Journal of the American Heart Association reports that flu (and other viruses, including COVID) can dramatically increase your risk of stroke or heart attack in the weeks following your infection. According to the research, there is a clear association between viral infections and heart disease and stroke, and the more you can protect yourself from infection in the first place, the lower your risk of these potentially serious or even fatal heart conditions. In sum, flu vaccines play an important role in lowering or even preventing your risk of cardiovascular disease. To find out more, read here, and for more pointers on how to lower your risk for flu, wash your hands, and click here.