Dr. Michael Teng
By Ryan Hughes, University Communications and Marketing
Flu levels are elevated and continuing to rise during the 2026 season, with Influenza A emerging as the dominant strain.
People across the country, including in the Tampa Bay area, are coping with the latest surge of illness. The virus is contributing to a growing number of hospitalizations.
Dr. Michael Teng, an associate professor in the Division of Allergy & Immunology at USF Health, studies how host-virus interactions drive viral disease. He answered questions about what's behind this season's surge and what people should know to stay healthy.
How is the flu outbreak different from what we've seen in previous seasons and who is at greatest risk?
Seasonal influenza is caused by two types of influenza virus: A and B. Within influenza A, there are two strains that predominate: H1N1 and H3N2. Ninety-percent of influenza cases spreading right now are caused by the H3N2 strain.
What is different this year is that the circulating H3N2 strain has several mutations that appear to allow the virus to avoid our pre-existing immunity. This means that more people will be infected and become sick. There does not seem to be a difference in symptoms and disease with the new H3N2 strain compared to previous years.
The people at higher risk are also the same as in previous seasons: children under 5, people over 65 and those with chronic medical conditions, such as asthma and heart disease.
Can someone still get the flu shot, and if so, is it effective against the current strain(s)?
The flu shot is still available at most pharmacies and still a match for the H1N1 and B strains that are circulating. The new mutations in the H3N2 strain have likely decreased the efficacy of the vaccine against the H3N2 strain, although there should still be some protection from severe disease. It is important to get the vaccine sooner rather than later because it takes up to two weeks for your immunity to build after immunization.
When should someone seek medical attention for the flu as opposed to dealing with it at home?
For most people, flu can be managed at home with over-the-counter medication and symptoms will resolve within a week. However, people with a high fever (>104oF), trouble breathing or dehydration should seek medical attention immediately.
How can people reduce the spread of the flu at home, work, school, etc.?
The best ways to reduce the spread of flu are the mitigation measures we are used to with SARS CoV-2: get vaccinated, avoid close contact with sick people, stay home when you are sick, cover your nose and mouth, hand washing/sanitizing. Influenza is spread by large aerosol droplets, so distancing and masks are effective against flu.
Anything else of importance?
Since the symptoms of flu resemble those of other respiratory viruses like SARS CoV-2, it is important to test if you have flu-like symptoms. There are rapid antigen tests that can distinguish influenza A, influenza B, and SARS CoV-2. Early testing is particularly important in those at higher risk as antiviral drugs against influenza A and SARS CoV-2 are most effective within two days of symptom onset.
