The new flu pill joins Tamiflu and other antiviral meds as options for treating influenza. But doctors still say the flu shot is the best way to protect yourself.

For the first time in nearly two decades, the U.S. Food and Drug Administration (FDA) has approved a new flu drug for the treatment of influenza. The new medication, called Xofluza (baloxavir marboxil), joins Tamiflu and other antiviral medicines as available options for people who get sick—and want to feel better faster—this flu season.

Xofluza is approved for people 12 and older who have had flu symptoms for no more than 48 hours. When taken within this time period, “antiviral drugs can lessen symptoms and shorten the time patients feel sick,” said Debra Birnkrant, MD, director of the Division of Antiviral Products in the FDA’s Center for Drug Evaluation and Research, in a statement yesterday.

“Having more treatment options that work in different ways to attack the virus is important,” she added, “because flu viruses can become resistant to antiviral drugs.” (Don't ditch your Tamiflu just yet, though: The U.S. Centers for Disease Control and Prevention says that the “vast majority” of flu viruses circulating today are still sensitive to all of the drugs currently approved for the treatment of influenza.)

In clinical trials involving more than 1,800 people, those who took Xofluza had shorter durations of flu symptoms, on average, compared to those taking a placebo. Xofluza was also tested against Tamiflu in one study, and there was no difference in duration of symptoms between the two groups. The most common side effects in people taking Xofluza included diarrhea and bronchitis.

According to a press release from Genentech, Xofluza's parent company, the drug can reduce flu symptoms “by more than a day” with a single oral dose. Xofluza works differently than other antiviral medicines: It’s the first to block an enzyme called polymerase acidic endonuclease, which the flu virus needs to replicate itself.

Tamiflu, on the other hand, attacks the flu virus itself, and it should be taken twice a day for five days. Unlike Xofluza, Tamiflu is also approved for children 2 weeks old to 12 years (with dosage based on the child’s weight), and is available as a table or a liquid. Two other antiviral drugs—one inhaled and one intravenous—are also approved to treat the flu in the United States.

Waleed Javaid, MD, director of Infection Prevention and Control at Mount Sinai Downtown Health System in New York City, says the fact that Xofluza works via a different mechanism probably won't make much difference to sick patients. "The question, really, will be how well does it perform and how quickly do we see improvement," he says. "It seems that it will be very similar to the current drugs, but I think it's a little too soon to know for sure."

A Xofluza tablet will cost $150, but coupons will be available to lower the cost to "as little as $30" for patients with health insurance, according to a spokesperson for Genentech. The company says that the drug will be available across the United States, with a doctor’s prescription, in the coming weeks.

Millions of Americans get the flu every year, and many get seriously ill or die. Last year was one of the worst flu seasons on record: An estimated 80,000 Americans died of influenza or related complications.

Dr. Javaid stresses that antiviral drugs like Xofluza and Tamiflu are not a substitute for getting a flu shot. Xofluza is also not approved for children younger than 12, one of the groups most vulnerable to complications from the flu.

"This is another drug in the arsenal for providers to treat a deadly illness called influenza," says Dr. Javaid. "But what remains even more important than having a new drug is having the vaccine. We have that vaccine, and that's still much better than getting ill with influenza and getting treatment."

The CDC recommends getting vaccinated by the end of October; it's one of the safest and most effective ways to prevent yourself and loved ones from getting the flu or developing serious flu-related complications.

Just today, the CDC released data showing that last year’s adult flu vaccination rates were down 6.2 percentage points from the previous year, at just 37.1%—the lowest rate since the 2010-2011 season. Experts say this may be one reason last year’s flu season involved so many illnesses, hospitalizations, and fatalities.

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