As summer vacations wrap up, schools begin again and temperatures begin to dip, Americans are falling back into their usual routines.
And one task to put on the fall to-do list is get your annual flu vaccine, experts say.
Last year’s respiratory season in the US brought about a ‘super flu’ surge driven by subclade K, a highly mutated variant of the Influenza A (H3N2) virus that caused a rapid and severe spike in cases nationwide.
The 2025-2026 respiratory season saw at least 32 million flu cases, according to the Centers for Disease Control and Prevention (CDC). There were about 390,000 hospitalizations and 24,000 deaths.
Influenza, commonly known as the flu, is one of the most common and highly contagious respiratory infections, impacting around eight percent of the US population each year.
The infection can cause symptoms such as body aches, headaches, fever and a cough and can lead to more serious complications including pneumonia and influenza-associated encephalopathy (IAE) a severe, brain dysfunction condition.
Doctors recommend an annual flu vaccination to help lower the chances of being infected, but when exactly is flu season and is there such thing as getting the shot too early?
Flu season normally starts in October, with infection rates peaking in December through February, and then dwindling down by springtime, per the CDC. As of September 5, there is minimal activity level for flu cases in the US.
Doctors recommend an annual flu vaccination to help lower the chances of being infected
The shot provides protection for about six to eight months, so experts say timing matters. Getting vaccinated too early could mean protection wears off before flu season ends.
While pharmacies start stocking the vaccine in August and promoting it in September, doctors agree these months are still too early to get the shot.
October is the ideal month to get vaccinated, with the CDC recommending vaccination by Halloween for the upcoming 2026-2027 respiratory season.
‘October is when I recommend getting the vaccine as there is more actual influenza activity then – there is very little now,’ Infectious disease expert Dr Amesh Adalja, told Prevention.com.
‘The vaccine will last further into the season if administered in October,’ Adalja added.
One exception for an early flu shot is children under eight years old who have never received one – as they would need two doses spaced apart to build immunity.
Additionally, people at high risk of flu complications, such as those with asthma, may want to consider getting vaccinated earlier.
There are three different flu virus strains that cause illness: influenza types A, B and C.
Influenza type A can infect people and animals, while type B is usually found only in humans and is generally associated with less severe infections.
Type C occurs much less frequently than A and B and causes minor illness in humans.
The seasonal flu shot, which is updated every year as the virus mutates, protects against influenza types A and B, as these are the most common and severe strains.
Symptoms of the flu include fever, cough, sore throat, stuffy nose, headaches and fatigue. While most people recover within a week, some may develop complications such as pneumonia, which can be life-threatening and require medical treatment.
The flu shot is one of the most effective preventative measures against infection, reducing the risk of doctor visits by 34 percent and the risk of hospitalization by 30 percent per the CDC, but it can take up to two weeks for the body to develop antibodies after receiving the vaccination.
Because of this, doctors recommend getting the shot a few weeks before an event or gathering where large numbers of people will be indoors.
As of September 5, the US is facing a minimal activity level of flu cases
Anyone can catch the flu, but those most susceptible include people 65 years and older, those with chronic medical conditions, pregnant women, and children under five.
Last year’s dominant strain, dubbed the ‘super flu,’ was brand new to people’s immune systems, making them highly vulnerable and at an increased risk of severe, hospitalizing illness.
While symptoms were the same as other flu strains, experts warned the ‘super flu’ variant was causing more severe illness, especially in children, with signs including week-long fevers and a cough that led to trouble breathing.
Super flu’s symptoms appear to be similar to previous influenza A strains, though doctors have noted they could be more severe.
Health officials recommend regular handwashing and avoiding contact with people who have flu-like symptoms.
Treatment includes rest, staying hydrated, taking over the counter medication such as Mucinex, or in severe cases, prescription antivirals such as Tamilflu.
