One of the reasons this season is especially brutal is that the most frequently reported influenza virus circulating is the H3N2 subtype of influenza A. “H3N2 is the dominant strain, and H3N2 seasons are more severe,” says William Schaffner, MD, a professor of preventive medicine and health policy at the Vanderbilt University School of Medicine in Nashville, Tennessee. The Centers for Disease Control and Prevention (CDC) warns that “in recent past seasons in which A(H3N2) viruses predominated, hospitalizations and deaths were more common, and the effectiveness of the vaccine was lower.” “H3N2 isn’t the only strain around," says Dr. Schaffner. “We’re also seeing H1N1 and influenza B, which the flu vaccine does better against.” Still, more than 17,000 people have been hospitalized for the flu so far this season. “Overall, hospitalizations are now significantly higher than what we’ve seen for this time of year since [the CDC’s] current tracking system began almost a decade ago, in 2010,” the acting CDC director Anne Schuchat told reporters at a press briefing.
When and Why Should You Take Tamiflu?
Tamiflu (oseltamivir) is one of three antiviral drugs approved by the Food and Drug Administration (FDA) and recommended by the CDC. The other drugs are peramivir, which is administered intravenously, and zanamivir (such as Relenza Diskhaler), which is inhaled. “Tamiflu is the most widely used antiviral because it’s taken orally,” Schaffner says. The CDC recommends that antivirals be given as early as possible to patients once flu-like symptoms develop. “Tamiflu has the best effect when it’s taken within 48 hours [of the onset of flu symptoms]. Though some studies indicate benefits beyond 48 hours,” says Schaffner. Most people who get the flu don’t require treatment with antiviral drugs, and they may not be prescribed to people with mild illness who are otherwise healthy. When it is prescribed, Tamiflu can lessen and shorten the effects of the flu. “It can reduce the duration of symptoms by a half or a full day,” according to Schaffner. “You’re also less likely to get complications and be hospitalized.” Antiviral treatment is recommended for anyone already hospitalized with the flu. It’s also prescribed “for people in outpatient treatment who are more likely to develop severe complications, such as adults 65 and older, young children, people with heart disease, lung disease, or diabetes, immunocompromised patients, and pregnant women,” Schaffner adds. The CDC recommends Tamiflu for treating the flu in pregnant women because “changes in the immune, respiratory, and cardiovascular systems that occur during pregnancy” raise the risk for flu-related complications. Tamiflu is designated a “Pregnancy Category C” drug, which means that it hasn’t been studied in pregnant women. But the CDC says the drug’s benefits are more likely than possible risks of harm to a pregnant woman or her baby. Tamiflu is sometimes prescribed preventively to people at high risk for the flu and potential complications. “It may be used prophylactically in people living in confined environments like senior citizen centers or nursing homes where influenza can spread very rapidly,” says Schaffner.
What Are the Common Side Effects of Tamiflu?
As with any medication, Tamiflu has potential side effects. Nausea and vomiting are not uncommon. “These side effects are usually an annoyance, but lots of vomiting adds to the dehydration risk that comes with the flu,” says Schaffner. Severe dehydration is a medical emergency and may require treatment with intravenous fluids. Signs of dehydration in children include lethargy, fewer or lighter wet diapers, and fewer tears when crying. Adults can develop a dry mouth, urinate less, produce darker-colored urine, and feel light-headed.
Is Tamiflu Safe for Children?
Tamiflu is recommended by the CDC and the American Academy of Pediatrics (AAP) for early flu treatment, regardless of the patient’s age. Treatment with antivirals also reduces the incidence of ear infections and the need for antibiotics in children 12 years of age and under, according to the CDC. Like adults, children taking Tamiflu may experience nausea and vomiting. However, reports from Japan provided evidence of neuropsychiatric symptoms such as hallucinations, hyperactivity, and seizures in children and adolescents taking the drug. “At the time in Japan, doctors were prescribing higher doses over longer periods of time,” which may have been contributing factors, says Schaffner. Reports have surfaced recently in the United States about similar side effects in children taking Tamiflu. In January, a North Texas family said their 6-year-old daughter suffered hallucinations and tried to jump from her bedroom window after taking the drug. More recently, the Indiana parents of a 16-year-old who committed suicide believe the medication was to blame. The prescribing information for Tamiflu includes the following warning: “Patients with influenza, including those receiving Tamiflu, particularly pediatric patients, may be at an increased risk of confusion or abnormal behavior early in their illness.” Schaffner estimates that these effects are rare, occurring in less than 1 percent of pediatric cases. “Sometimes doctors will decide not to treat with Tamiflu” after weighing its potential benefits and risks, Schaffner says. But “influenza is a very nasty virus,” he cautions. “A child can look stable and within hours wind up in the ER.”
