This story was updated on Nov. 20, 2018.

Flu season is just getting under way and, according to the Centers for Disease Control, the single best way to ward off the virus is—you guessed it—to get a flu shot.

What you may not know: the best time to get the shot (it’s never too late during flu season but some months are better than others); the best vaccine to ask for (there are several kinds); where to go for it (Costco, anyone?), how much it will cost; and how effective it will be.

Here’s what you need to know about this year’s flu shot.

Okay, so when should you get the flu shot?

The flu vaccine is now widely available in most doctors’ offices and pharmacies, where it tends to be prominently marketed.

Although the optimal date to get the vaccine was by the end of October, you’re still well within prime time for the shot, according to the Centers for Disease Control—especially if you do it within the next week or two. That’s because it typically takes about two weeks for the antibodies that protect you against the virus to kick in and the peak period for catching the flu runs from December to February. 

Research suggests the vaccine’s effectiveness begins to drop after four months, especially in older adults.

In fact, it’s probably better to get it a little later than the CDC’s recommended October date than too early. That’s because research suggests the vaccine’s effectiveness begins to drop after four months or so, especially in older adults. Since flu season typically runs from October to March but can last until May, getting your shot too early could leave you more vulnerable to the disease later on.

Can’t get to the doctor or pharmacy for your shot this month? Don’t worry.

“It’s never too late to get vaccinated,” says Litjen Tan, chief strategy officer for the Immunization Action Committee and former director of infectious disease, immunology, and molecular medicine at the American Medical Association., “even in December or January.”

Which type of shot should you get?

There are several different types of flu vaccines, all of which have been updated for the 2018-19 flu season to better match the viruses that will be circulating. Nearly all of this year’s varieties will be quadrivalent vaccines, which protect against four different strains of flu.

If you’re 50 or older but younger than 65, any of the regular-dose vaccines are fine, except for the nasal spray, which is recommended for people up to age 49.

“It’s never too late to get vaccinated, even in December or January.”
Litjen Tan, chief strategy officer
Immunization Action Coalition

Those 65 and older, who are particularly vulnerable to the flu and often get sicker when they come down with it, should ask for one of two stronger vaccines available. That means either a high-dose version,  Fluzone High-Dose, that contains four times the amount of antigen as a regular flu shot; or FLUAD, a vaccine with adjuvant, an ingredient that creates a stronger immune response.

Where should you get the shot?

You can get the vaccine from your doctor, drugstore chains, most local pharmacies, many supermarkets and big-box stores (think Costco, Walmart, or Target) and, increasingly, your workplace. According to a study last year from the Society for Human Resource Management, nearly 60% of employers now offer on-site flu vaccinations.

Does it matter where you go for yours? Not from an effectiveness standpoint, says Tan. He suggests, “Just get the shot where it’s convenient for you.”

How much will the vaccine cost?

For most people with health insurance, the flu shot is free.

The Affordable Care Act requires both government and private health plans to cover all vaccines recommended by the Centers for Disease Control, including the flu shot. Medicare also covers the shot at no cost, while Medicaid covers flu shots for children from six months to four years and adults over 50, plus older children and younger adults with certain health issues.

If you have private insurance, check with your provider to find out if you must visit a specific facility to get your flu shot for free. Many plans cover flu shots given at pharmacies, though some people end up paying out-of-pocket because it’s more convenient than filing an insurance claim, says Tan.

Regular flu shots given in chain pharmacies like CVS and Walgreens generally run $40 to $50. Costco offers shots for around $20 ($19.99, to be precise). The high-dose vaccine may cost more, around $70.

If you do not have insurance, your local health center (find yours here) or state health department may offer free or low-cost flu shots.  

Is the flu shot safe and effective?

Cross safety off your worry list. “I can’t stress enough that the flu shot is an incredibly safe vaccine,” says Tan.

It is a myth that the flu shot can give you the flu. The vaccine takes 10 to 14 days to become effective after getting the shot, says Dr. Tan, so exposure to the flu in that window may make you sick.

The flu shot typically lowers your risk of getting sick by 40% to 60% and reduces the severity of the disease if you do catch it, according to CDC studies. Still, in any particular year, how effective the vaccine will be is the “million-dollar question,” says Tan, since the viruses in circulation change from year to year.

You can further reduce your chances of getting the flu with some simple, commonsense precautions: Stay away from people who are sick and wash your hands frequently, which has been shown to reduce the spread of the disease by up to 50%.

Purell, anyone?