Each year, experts work to forecast the strains of flu that are most likely to emerge. For the 2017-2018 flu season, which is just ramping up, nailing this appears to be as challenging as ever.

“It’s incredibly hard to predict even what [strain of the] virus will circulate in the coming year,” says Lynnette Brammer, M.P.H., an epidemiologist with the Centers for Disease Control and Prevention’s influenza division. And, she adds, “it’s hard to know how severe the season will be.”

More on the flu

What Brammer and other experts are clear on is that the most important way to fight the flu is the annual vaccine. And while the vaccine for this viral illness is recommended for just about everyone who is 6 months or older (including pregnant women), it’s especially important for those who are most vulnerable to the flu’s more severe effects.

That includes older adults and young children. For example, the flu can bring seven or more days of aches, fever, cough, and headache to most who contract it. But older adults and those with underlying health problems, such as asthma, diabetes, or heart disease, are more likely to have complications such as pneumonia, be hospitalized—or even die.

The vaccine’s effectiveness varies, depending on how well-matched it is to the flu strains that end up circulating. But it usually cuts your risk by about half, says Kathleen Neuzil, M.D., professor of medicine and director of the Center for Vaccine Development at the University of Maryland School of Medicine. Additionally, she says, with a flu shot, you’re much less likely to be hospitalized or to die from the disease.

Here’s what else you need to know about how to fight the flu this year.

When to Get It

October is a good month to get the flu vaccine, because flu activity is usually still low, according to Brammer. “For the vaccine to do the most good, you need to get it before viruses are circulating widely,” she says. It can take two weeks to fully build up your immunity.

But if your timing is off, get the vaccine when you can. The flu usually doesn’t peak until January or February and can circulate for a month or two afterward, so getting the shot later than October will still help you fight the flu.

Consider receiving the vaccine in the morning. A recent University of Birmingham study found that vaccines given between 9 and 11 a.m. led to higher levels of protective antibodies to two out of three flu strains than those given between 3 and 5 p.m.

The researchers haven’t yet looked at whether a morning shot offers more protection, but “more antibodies in principle relate to better resistance,” says study leader Anna C. Phillips, Ph.D.

Which Vaccine Is Right for You?

The standard flu shot protects against the three or four strains that are predicted to be most common—many flu viruses can circulate in a given year. A preservative containing a form of mercury is used in a few formulations of the flu shot. (Evidence suggests this mercury compound is harmless, but you can request a vaccine without it, if you choose.)

Those who are 65 or older can speak to their doctors about whether they’d benefit from a high-dose vaccine (Fluzone High-Dose), which is four times stronger than the standard shot, or the adjuvanted vaccine (Fluad), which has an additive designed to elicit a more robust immune reaction.

As you age, your immune system may become less responsive, and studies suggest that both of these vaccines are better at preventing flu in this age group than standard flu shots. Flublok Quadrivalent, approved last year, may also provide better protection for people 50 and older.

Of the three options, says John Treanor, M.D., director of the New York Influenza Center of Excellence, “The one with the strongest evidence of proved protection is the high-dose vaccine.”

And be aware that for the second year in a row, the CDC is advising against using the nasal spray FluMist, which is delivered by a quick spray in the nose. It has not protected against the flu as well as standard flu shots of late, according to a committee of experts that advises the CDC. (In recent years, FluMist accounted for about one-third of flu vaccines given to children; some adults also used it.)  

Instead, opt for a standard flu shot for youngsters. According to a 2017 study in the journal Pediatrics, the vaccine reduced flu-related deaths in children by 65 percent.

If you’re between ages 18 to 64 and find injections uncomfortable, you can ask about getting the vaccine with a smaller needle that only pierces the skin—the traditional shot is injected into the muscle, which can be more painful.

Know How to Avoid Germs

A few simple lifestyle steps can also help shield you from the flu. For example, because dry air helps the flu virus live longer, consider using a humidifier to keep humidity at 30 to 50 percent, drink plenty of water, and minimize your intake of alcohol, which is dehydrating. Avoid touching your nose and eyes to reduce the chance of transferring any virus you might have on your hands.

Wash your hands often with soap and water for 20 seconds (two rounds of “Happy Birthday”). Or use hand sanitizer with at least 60 percent alcohol. 

If You Get the Flu Anyway

Rest, keep yourself hydrated, and if you have fever, headache, and achiness, opt for acetaminophen (Tylenol and generic), ibuprofen (Advil and generic), or naproxen (Aleve and generic).

Ask your doctor for a prescription for an antiviral medication right away if you develop a fever, cough, and body aches and you’re 65 or older, obese, or have a compromised immune system or a chronic health concern. Your pediatrician may recommend antivirals for children who have severe flu or chronic health conditions like asthma, diabetes, or heart or lung disease.

An antiviral medication can shorten the flu by one to three days, ease symptoms, and cut the risk of complications, but only if you start it within 48 hours of getting sick.

Avoid cough suppressants (flu coughs usually go away on their own) and antibiotics, which don’t work for viral infections. In addition, taking antibiotics when they’re unnecessary can contribute to antibiotic-resistant bacteria.

See your doctor if your flu symptoms start to improve, but then fever returns and your cough worsens, or if you experience difficulty breathing, pain in the chest or abdomen, dizziness or confusion, and severe or persistent vomiting.

— Catherine Roberts contributed additional reporting.