Flu season: Vaccines, symptoms and more

As flu season approaches, everyone should take precautions to avoid contracting the virus, which can significantly impact your health. Dr. Pedro Piedra, professor of molecular virology and microbiology at Baylor College of Medicine, explains updates to the flu vaccine and what you need to know about flu symptoms in children and adults.'

Flu vaccine updates

The flu vaccine gets updated yearly. For the 2025-2026 flu season, one of the vaccine's three components, the H3 antigen targeting influenza A (H3N2), has been updated, while the influenza B and H1N1 components remain the same as last year. There is also FluMist, a nasal spray that contains the live attenuated influenza vaccine.

"This (FluMist) is now available for self-administration of adults and administration by adults to their children," said Piedra. "FluMist is only approved for individuals 2 through 49 years of age."

The recombinant flu vaccine, previously approved for adults 18 years and older, is now approved for children 9 years of age and older. Also, it is recommended by the U.S. Centers for Disease Control and Prevention that children, adults and pregnant women should only receive single-dose vaccines that don't contain thimerosal.

"Everyone 6 months of age and older is recommended to receive one of the flu vaccine types that are available," Piedra said.

Flu symptoms

Flu symptoms can look different in children under the age of 5, compared to older children and adults. Piedra says that in young children, it's difficult to discern flu from other respiratory viruses because the symptoms are similar. Young children with flu symptoms:

• Will feel tired.
• Have a sore throat.
• Get a runny nose.
• Feel achy, feverish.
• Can sometimes have gastrointestinal manifestations such as vomiting, abdominal pain or diarrhea.

For older children and adults, the flu can start with an abrupt illness. It is highlighted by:

• Fever/feverishness.
• Muscle aches.
• Headaches.
• A sore throat progressing to nasal congestion and a runny nose.
• Can sometimes develop gastrointestinal manifestations such as vomiting, abdominal pain or diarrhea.

"This can last several days, and you just don't feel well at all. When you start to recover, it can take a while before you start feeling like yourself," said Piedra.

Who is at risk of becoming severely ill?

"Flu vaccinations are safe. They have been given to millions of individuals for many years, making them a good way to help maintain health. Getting influenza is not fun, and for some individuals, it's deadly," Piedra said. "Flu can go beyond the lungs and affect other organ systems in your body, such as the brain, heart, muscles, gastrointestinal tract and kidneys."

Several groups of people are at risk of getting severely ill from the flu and other respiratory illnesses.

"Young children, particularly those under 2 years of age, are at a higher risk for hospitalization, children and adults with underlying health conditions (heart, lungs, diabetes, obesity, neuromuscular, immunodeficiency, cancer, etc.) and older or elderly adults about 60 to 65 years of age and older," Piedra said.

Piedra adds that if you are part of one of these risk groups, have an underlying disease, have an immune deficit or are exposed to older adults and young children, ask your physician how you can quickly get a prescription for an antiviral against the flu if you were to get it. Talking to your physician about strategies for early intervention is crucial.