This year is proving to be a challenging one when it comes to fighting the flu. As of January 13, this season's flu is responsible for more than 9,000 hospitalizations—and 30 deaths in children alone, according to the Centers for Disease Control and Prevention. (See the CDC flu activity map, below.)

What's more, the CDC estimates that this year’s vaccine is only 32 percent effective in providing protection against the H3N2 strain of the flu—the predominant one currently circulating. (But it’s still important to get vaccinated).

If you get the flu, your doctor can prescribe an antiviral medication such as oseltamivir (Tamiflu and generic) that can help relieve symptoms and get you back on your feet a bit faster. But antivirals can have side effects, and not everyone with the flu needs them. Here, answers to pressing questions about these drugs.  

What Are Antivirals Anyway?

Tamiflu is the best-known of the prescription flu antivirals—drugs that can ease symptoms and shorten the course of the illness by inhibiting the growth of the flu virus in the body.

More on the Flu

For those who may need an antiviral, the CDC is recommending one of three for use this flu season: Tamiflu and its generic (in pill or liquid form), zanamivir (Relenza, an inhaled powder), and the IV drug peramivir (Rapivab, which is reserved for very sick, already hospitalized flu sufferers).

Most people prefer Tamiflu or its generic, because it’s easier to take a pill or drink a liquid than to inhale a powder. Both Tamiflu and its generic and Relenza are usually prescribed for 5 days, while one dose of Rapivab is given via an IV for 15 to 30 minutes.

It's important to know that these drugs are not a type of antibiotic. Antibiotics are used to fight bacterial infections and should not be used for viral infections like the flu.

How Effective Are Antivirals?

“All three drugs work in the same way and have similar effectiveness rates,” says William Schaffner, M.D., professor of preventive medicine and an infectious disease specialist at Vanderbilt University in Nashville.

Research shows that when given within 48 hours of the onset of flu symptoms—such as fever, cough, sore throat, body aches, and chills—these drugs lessen a person's sick time by about 17 hours in adults and 29 hours in children.

They also ease the intensity of symptoms and help prevent more serious complications from the flu, such as pneumonia.

There may be some benefit in taking antivirals even outside of that 48-hour window. One 2013 CDC study published in The Lancet Infectious Diseases found that children given oseltamivir within five days of getting sick experienced an improvement in symptoms.

They also had significantly less virus shedding, which means they were much less likely to spread the illness to others.

Who Should Take Tamiflu?

If you’re in good health and come down with the flu, you don't necessarily need Tamiflu or another antiviral medication, because you’ll most likely get better on your own within one to two weeks using self-care strategies, such as rest, getting plenty of fluids, and over-the-counter pain relievers to relieve fever, headache, and muscle aches.

“By the time most people drag themselves out of bed to see the doctor, they’re on the road to recovery already,” says Nicole Bouvier, M.D., an infectious disease specialist at the Icahn School of Medicine at Mount Sinai in New York City.

People at high risk for flu complications, however, should take an antiviral medication. This includes people over age 65, kids 5 and under—especially those below age 2—pregnant women and those up to two weeks postpartum, and people who live in nursing homes. (Find the entire list here.) 

In the above cases, and for those with respiratory conditions such as asthma or chronic obstructive pulmonary disease (COPD), says Schaffner, “they can make the difference between having a milder course of illness and ending up in the hospital.” (Note that because Relenza is inhaled, it shouldn't be taken by anyone with asthma or COPD.)

In addition, “if anyone’s sick enough to already need to be in the hospital, and they come down with the flu, they absolutely should be on one,” Bouvier says. 

If you have a loved one in a nursing home or assisted-living facility, they should also receive an antiviral if there’s a flu outbreak there, even if they aren’t sick themselves, Schaffner says.

According to the CDC, if at least two residents get the flu within three days of each other, everyone should get a drug like Tamiflu for at least two weeks, and continue for at least a week after the last case has been identified.

For normally healthy people, consider requesting an antiviral if you feel really awful and simply can't wait out the time needed for symptoms to ease, says Marvin M. Lipman, M.D., Consumer Reports' chief medical adviser.

"Even if you're basically healthy, the flu can be a devastating experience and leave you exhausted for weeks afterward. Don't be a hero or try to bite the bullet," he says. "And if you have an elderly or infirm person in your household, think in terms of using the medication to prevent spreading the virus to others."

Do Antivirals Have Side Effects?

The most common side effects for Tamiflu and its generic are headache, nausea, and vomiting—but taking the drug with food can minimize stomach discomfort. Diarrhea, fever, nausea, and body aches have been reported for Relenza. Diarrhea can occur with Rapivab.

There have also been rare reports of psychiatric side effects such as delirium and hallucinations with Tamiflu and its generic and Relenza, mostly in children. Let your doctor know right away if you notice anything like this. 

How Much Do Antivirals Cost?

Thes cost to you will vary, depending on your insurance plan. But they can be a bit pricey, although the 2016 introduction of generic Tamiflu has helped.

If you don't have health insurance or your insurer doesn't adequately cover Tamiflu, its generic or Relenza (or doesn't cover them at all) you may be able to get a coupon online that can help you save.

For instance, GoodRx offers a coupon that allows you to purchase generic Tamiflu for just under $52 at Walmart. HealthWarehouse has generic Tamiflu for $85, a significant savings on the brand name drug at $165.  We also found Relenza at Costco for $65 with a GoodRx coupon.

Are There Shortages of Tamiflu?

You probably won't have difficulty obtaining an antiviral if you need one, although there have been reports of temporary shortages of Tamiflu and its generic at various pharmacies in California, which has been hit especially hard by this season’s flu.

“The manufacturers produced enough—it’s just that some pharmacies may not have ordered enough and as a result may be temporarily out of stock,” Schaffner explains.

If that’s the case, you may have to call around to different pharmacies to find one in your area that has the drug.

See How the Flu Spreads Across the U.S.

Below you'll find the CDC's weekly influenza surveillance report. By clicking on the play button you can see how influenza activity has changed over the past several months. (You can also view these maps for past flu seasons via the season dropdown.)

Interactive courtesy of the CDC