Got Flu? The Next Steps

“Older adults and other groups at risk for severe complications from influenza infections often do not receive flu antiviral prescriptions in urgent care and emergency department settings…”

Stephanie Soucheray, MA, CIDRAP News, April 14, 2025, citing recent study in Clinical Infectious Diseases

“Our viruses unite us, even when our politicians do not."

Daniel Altman, British immunologist, and Angela Rasmussen, American virologist

The flu season runs from October to May each year with the worst months being December through February. While most of this year’s flu season is behind us, it’s good to remember the words of Yogi Berra who cautioned, “It ain’t over ’til it’s over.”

The seasonal flu causes about 40 million illnesses and 28,000 deaths each year in the U.S. Recent publications suggest many Americans can benefit from a quick update on the flu, including the benefit of early treatment with the oral antiviral drug Baloxavir marboxil (Xofluza). In this week’s post, I provide a brief flu update focusing on steps to take whenever you think you might have the flu.

What is influenza? The influenza virus is one of many viruses that attack the respiratory tract. (Influenza A H1N1 and influenza H3N2 are the main viruses that caused this year’s seasonal flu.) And, it is one of the only respiratory tract viral pathogens for which antiviral treatment is available.

What are the symptoms of the flu? If at any time during the flu season you develop one or more of these symptoms: cough (dry or with phlegm), fever, chills, muscle aches, headaches, sore throat, fatigue, or loss of appetite, consider the possibility that you have the flu. As the severity of these symptoms is of little help in sorting out what virus got hold of you, get a test—an at-home rapid antigen flu test.

Diagnostic tests are available. In the past two years, establishing a diagnosis of influenza has become much easier. Rapid antigen tests, such as Walgreen’s  “SpeedySwab Rapid COVID-19 & Flu A/B Antigen Self-Test,” are now readily available. These tests can detect influenza A and influenza B viruses in a nasal swab specimen within 20 minutes. In addition, they can also pick up SARS-CoV-2 virus, the cause of COVID-19, which is in the differential diagnosis of viral respiratory tract infections.

Get treated. If a rapid antigen test for influenza A and B confirms your suspicion that you have the flu, or if the test is negative but the severity of your illness suggests that what you have is not just one of the viral causes of the “common cold,” the next step is to contact your healthcare provider. Report your symptoms and test results to your health care provider and ask about a prescription for treating your viral infection.

The treatment options for influenza A and B in the outpatient setting are the antiviral drugs Baloxavir (Xofluza) or Oseltamivir (Tamiflu). The Centers for Disease Control and Prevention generally considers Baloxavir a better option than Oseltamavir for flu treatment, especially for those at high risk of complications. This is due to Baloxavir’s superior efficacy in shortening the duration of illness and reducing the spread of influenza virus. (On April 24, 2025, the New England Journal of Medicine reported the results of a randomized, placebo-controlled trial that highlighted the efficacy of Baloxavir treatment in preventing transmission of influenza virus showing a 29% reduction in household flu transmission.)

The advantages of Baloxavir also include convenience—a single dose as opposed to twice a day dosing for five days with Oseltamavir—and fewer side effects. Although Baloxavir may be more costly, its higher cost is largely offset by the single vs multiple dose regimen of Oseltamavir.

Prevention of influenza (vaccines). Taking Baloxavir or Oseltamavir is recommended for asymptomatic individuals who are exposed to the virus in a household setting as prophylaxis to prevent influenza virus infection. Vaccine are considered, however, the mainstay of prevention.

The efficacy of influenza vaccines to prevent seasonal flu varies from year to year, and although they are safe, none of the vaccines is remarkably effective. Hence, ongoing research by government-supported programs, together with researchers in pharmaceutical companies, is a high priority.

Universal vaccines that are active against all influenza strains could materialize soon. The University of Cambridge-based company DioSynvax and Singapore’s Biolabs recently developed a next generation universal mRNA flu vaccine with the potential for oral mucosal delivery. (See, “New agreement geared toward universal avian flu vaccine,” CIDRAP News, April 22, 2025).

Roadblock to vaccine development. Given the astonishing success of rapid development of mRNA vaccines for the prevention of COVID-19, it appears that the scientific and technological knowhow are potentially there to do the same thing for influenza vaccines. But the politicalization of the field of vaccinology is making getting even routine childhood vaccinations a challenge. (See, “Backslide on vaccines puts millions at risk amid shrinking funds, global agencies warn,” World Health Organization, April 24, 2025).

Against this backdrop of political infighting and expanding vaccine misinformation, the University of Minnesota recently launched the Vaccine Integrity Project. (See “CIDRAP launches Vaccine Integrity Project to help safeguard US vaccine use,” CIDRAP News April 24, 2025). According to CIDRAP Director and University of Minnesota Regents Professor, Michael Osterholm, “This project acknowledges the unfortunate reality that the system that we’ve relied on to make vaccine recommendations and to review safety and effectiveness data faces threats.”

This project couldn’t have come at a better time; it is sorely needed. Moreover, knowing firsthand the talent of Michael Osterholm and the quality of the members that have been recruited to this team, I believe this innovative initiative has a good chance of success. For everybody’s sake, let’s hope so.