Preparing for the 2026-2027 Flu Season

“Vaccination is the single most important step people can take to protect themselves from influenza.”

Tom Frieden, American physician and former director of Centers for Disease Control and Prevention

“Continued efforts to undermine the safety and efficacy of vaccines are incredibly dangerous and will have grave consequences for children and families.”

David Freedman, professor emeritus of infectious diseases, University of Alabama

Influenza (flu) is an acute respiratory infection caused by the influenza virus. Seasonal flu imposes a substantial disease burden every year, straining healthcare systems and causing significant morbidity and mortality. For the 2024-2025 flu season in the U.S., the Centers for Disease Control and Prevention (CDC) estimates that 51 million people had symptomatic influenza, 71,000 were hospitalized, and 45,000 died from flu-related illness. As we are on the threshold of the 2026-2027 flu season, in this week’s post, I provide some guidance on preparing for it.

The influenza viruses (a recap). Influenza viruses are mRNA viruses that attack the respiratory tract. There are four major types: A, B, C, and D. Influenza A and B cause seasonal epidemics of disease in people.

The influenza A group of viruses is by far the most important in human infections. (Influenza A caused the 1918-1919 flu pandemic that killed an estimated 50 million people globally.) It has a high morbidity and mortality causing millions of illnesses and up to 650,000 deaths globally each year. It is highly contagious spreading easily from person to person through respiratory droplets from coughing, sneezing, and talking. And, it has the ability to constantly evolve (genetic malleability) allowing it to evade existing immunity and requiring annual vaccine updates.

Symptoms of influenza.  The common symptoms of influenza include: fever, chills, dry cough, sore throat, runny nose, muscle or body aches, headache, fatigue or extreme tiredness. Nausea, vomiting, and diarrhea can also occur, especially in children. (Even though vomiting and diarrhea can be symptoms of influenza, it is important not to confuse the flu, a respiratory infection, with what is commonly, but mistakenly, referred to as “the stomach flu,” a gastrointestinal infection caused by a virus—norovirus, rotavirus, or adenovirus—bacteria, or parasite.)

The illness usually lasts for 1-4 days, although fatigue and cough can linger for two or more weeks. And a recent study indicated that almost a third of patients continue to suffer with a runny nose, cough, or fatigue for four or more weeks after infection. (Hu, T, et al., “The one-month impact of influenza infection on patient-reported symptom burden among U.S. adults with a test-confirmed illness: a longitudinal study,” BMC Infectious Diseases, July 9, 2026).

In home test for influenza and SARS-CoV-2.  Influenza, COVID-19 and respiratory syncytial virus can cause many of the same symptoms. It is important, however, to know what virus is causing your illness as there are specific treatments for both influenza and SARS-CoV-2 (the cause of COVID-19) that may help you recover faster and avoid serious complications.

Fortunately, establishing a diagnosis of influenza has become much easier; there is a highly reliable multiplex test readily available at your local pharmacy that can detect influenza A and influenza B viruses in a nasal swab specimen within 20 minutes. In addition, the test can also pick up SARS-CoV-2 virus, the cause of COVID-19, which is in the differential diagnosis of viral respiratory tract infections.

Influenza virus and SARS-CoV-2 are the only respiratory tract viral pathogens for which there are antiviral therapies. But for these antiviral therapies to be effective, “timing is everything;” they should be taken within the first 48 hours of illness.  Therefore, if you suspect that you may have the flu, don’t wait; get one of these test kits, swab the back of your throat or nose and wait 20 minutes for the results.

Get treated. If your at-home multiplex test confirms your suspicion that you have the flu, contact your health care provider. Report your symptoms and test results to the health care provider and ask about a prescription for treating your infection.

The treatment options for influenza A and B in the outpatient setting are the antiviral drugs Xofluza (baloxavir marboxil) and Tamiflu (oseltamivir). Both are effective if taken early in the course of the illness (within 48 hours of the first symptoms).

Xofluza has the advantage of being a single-dose pill—"one and done.” It is, however, available by brand-name only causing it to be more expensive and possibly needing prior insurance approval. In addition, it is only available for adults and children 5 years of age and older.

Tamiflu requires twice-daily pills for five days for treatment but is available at lower cost in generic form (oseltamivir). It is also approved for very young children— infants as young as two weeks old. (There is a liquid formulation for young children). Due to its long safety history, Tamiflu is usually preferred for treatment during pregnancy or for very young children.

Get vaccinated. Vaccines are considered the mainstay of prevention of influenza. The efficacy of influenza vaccines to prevent seasonal flu varies from year to year, and although they are safe, to date, none of the seasonal flu vaccines has been remarkably effective. Thus, getting a seasonal flu shot won’t guarantee that you won’t get the flu; nonetheless, vaccination lowers the odds that you will get seriously sick or die from influenza.  (Boden, S, “High-dose flu shot cuts the odds of hospitalization among older adults,” CIDRAP News, June 8, 2026; Van Beusekom, M, “Estimated US flu vaccine efficacy against death in kids 80% over 8 seasons,” CIDRAP News, July 6, 2026).

The flu season generally lasts from October through May, and it usually takes about two weeks after vaccination for your body to build up enough protective antibodies. Therefore, the optimal time for getting your shot is during September and October thereby protecting you before the flu season ramps up and ensuring that your immunity doesn’t fade before the flu season ends.

The CDC routinely recommends a seasonal flu shot for everyone 6 months and older. Unfortunately, no flu vaccine for this fall has been approved by both the U.S. Food and Drug Administration (FDA) and the CDC. (Henderson, J, “What’s Going on With Fall COVID and Flu Shots?,” Medpage Today, August 14, 2026). In March, the FDA made its recommendations about vaccine compositions for influenza vaccines for 2026-2027. But, due to the chaos at the CDC, its recommendation on how to use those vaccines has not been firmed up. (The CDC’s Advisory Committee on Immunization practices hasn’t held its March or June meetings this year.) This has caused confusion as to which products are best for various age groups, and whether additional vaccine doses are needed for immunocompromised patients as well as other considerations.

The Infectious Diseases Society of America, the American Academy of Pediatrics, and the American Academy of Family Physicians have stepped in to fill the gaps and have issued guidance on fall respiratory virus shots.  To determine what vaccines are best for you, contact your doctor.

For those of you aged 50 and older, be aware that on August 6, 2026, the FDA granted full approval for Moderna’s mFLUSIVA, the first mRNA vaccine for this age group. In a Phase 3 trial, this vaccine was 26.6% more effective than a standard-dose flu vaccine at preventing influenza in adults ages 50-64 and its relative efficacy was 27.4% higher among adults age 65 and older. (Schnirring, L, “Moderna announces promising efficacy trials from mRNA flu vaccine trial,” CIDRAP News, June 30, 2025; Leroux-Roels, I, et al., “Efficacy and Safety of an mRNA Seasonal Influenza Vaccine in Adults,” New England Journal of Medicine, May 6, 2026).  mFLUSIVA is expected to become available at select locations during the 2026-2027 flu season, but availability and insurance coverage are still being worked out.  

The bottom line.  This year’s flu season arrives with an unusual wrinkle: due to disruptions at the CDC, official guidance on which vaccine to use for whom has been slower to come together than usual. The fundamentals of protecting yourself against the flu, however, haven’t changed.

Get vaccinated once a shot appropriate for you becomes available, ideally in September or October, and talk to your doctor if you’re unsure which vaccine fits your age group or health situation. Keep an at-home flu/COVID test kit on hand so that if flu symptoms hit, you’re not guessing whether you have the flu, COVID or just a “common cold.” And if that test comes back positive, call your health care provider right away, since antiviral treatment only works if you start it within 48 hours of your first symptoms. Vaccination, early testing, and prompt treatment, taken together, remain your best defense against the influenza virus—a virus that still hospitalizes and kills tens of thousands of Americans every year.