Got Flu? What to Do

Getting a flu shot isn’t a guarantee you won’t get the flu: The vaccines protect against the four strains of the influenza virus scientists predict will be most common each season, but if you’re exposed to a different strain, all bets are off. And because it takes about two weeks for immunity from flu to kick in post-vaccination, if you encounter a flu virus before that happens you could wind up sick.

And having the flu is no joyride, with symptoms more comparable to COVID-19 than to the common cold. Flu is associated with a range of complications as well — from ear infections to pneumonia — although again, if you’re vaccinated you’ll be far less likely to have complications, according to a report published in June 2021 in the journal Vaccine.

Whether you’ve been vaccinated or not, it’s important to understand how to recognize the symptoms of flu and if you or someone you care for winds up getting sick, to know the steps to take for a speedy recovery.

How to Know It’s Really Flu

First things first: In order to know how to manage flu, you’ll need to make sure that’s what you’re dealing with. For example, it’s easy to mistake flu for COVID-19, or even a common cold, as all three can cause a cough, chest discomfort, sore throat, runny nose, and fatigue.

But colds and COVID are caused by different viruses than influenza, so they do have some key differences. For one thing, “colds usually come on slowly, over several days, and cause mild illness,” explains Eric A. Weiss, MD, professor emeritus of emergency medicine at the Stanford University Medical Center in Palo Alto, California.

Flu, on the other hand, can hit you like a truck: You suddenly feel weak and find yourself overcome with abrupt chills, a fever that gradually rises, muscle aches, shortness of breath, and fatigue.

And like flu, COVID can cause severe illness, but is associated with a few unique symptoms. Chest pain is a common symptom for both, for example, but with flu it tends to be mild to moderate while COVID can cause persistent pain and interfere with breathing.

The CDC recommends managing flu with rest and drinking plenty of water to prevent dehydration. Acetaminophen (Tylenol) or ibuprofen (Advil, Motrin) can help ease muscle aches and relieve fever. Because the virus is highly contagious, staying home is also important so as not to spread the sickness to others.

When to Consider Antiviral Drugs

Antivirals don’t actually kill the flu virus. Instead, they stop it from replicating or reproducing in the body. They can be helpful whether you have been vaccinated or not.

When taken within 24 to 48 hours of when symptoms start, these prescription drugs make symptoms less severe and can shorten the amount of time you feel sick by about a day, says William Schaffner, MD, an infectious disease specialist and a professor of preventive medicine and health policy at the Vanderbilt University School of Medicine in Nashville, Tennessee.

Four antiviral medications are approved by the U.S. Food and Drug Administration to treat flu:

• Oseltamivir phosphate (Tamiflu), which comes as a capsule or liquid to be taken every 12 hours for five days
• Zanamivir (Relenza), an inhaled medication you take twice a day for five days
• Peramivir (Rapivab), given once via infusion (through a needle into a vein) by a healthcare provider; the treatment takes 15 to 30 minutes
• Baloxavir marboxil (Xofluza), a one-and-done single-dose tablet that must be swallowed within 48 hours of the start of symptoms

Experts don’t always agree about who should take antivirals for flu, but these medications generally are recommended for people who have severe flu symptoms or are at high risk for serious complications. If you fall into one of these categories, see your healthcare provider as soon as possible, as antivirals are most effective when taken early in the course of infection.

When the Going Gets Tough

Extreme flu symptoms require immediate medical attention. The most common are:

• A high fever (103 or above) or one that lasts four or more days
• Trouble breathing or shortness of breath
• Pain or pressure in the chest or abdomen
• Sudden or persistent dizziness or confusion
• Flu-like symptoms that seem to improve or go away, then get worse or come back

“If you’re getting worse, if you’re having difficulty breathing, or if you’re so sick you can’t keep fluids down and you’re getting dehydrated, you absolutely need to seek medical care,” says Dr. Schaffner.

He advises people who are especially vulnerable to flu complications — those over 65, pregnant people, and people with chronic illnesses — to be on the alert for extreme symptoms. Parents should also keep an eye on kids who come down with the flu.

How Vaccinations Help

The CDC advises everyone older than 6 months get a flu shot. Again, although the vaccine is not a guarantee you won’t come down with the flu, it’s estimated it can reduce the risk of illness by 40 to 60 percent.

What’s more, it’s never too late to get vaccinated, Weiss says. Although flu season peaks from December through February, it can last well into May. Also, the predominant flu strains circulating in a single season can change, so even if you get the flu early you should still get vaccinated to protect yourself from the possibility you’ll encounter a different strain later in the season.

Weiss advises people with mild upper respiratory infections (colds) get vaccinated even if they are sick, but people who have moderate to severe illnesses with or without a fever should wait until they recover or consult their doctor before getting vaccinated.

“Vaccination doesn’t influence the effectiveness of the treatment,” says Schaffner. “The vaccine makes it likely that you will have a less severe infection, but that doesn’t mean you shouldn’t get treatment in addition.”