By Caroline Shannon-Karasik
Oct 01, 2019 @ 5:30 pm
Brent Lewis/Getty Images

October is here, officially kicking off the month of Halloween and PSL everything. But the truth is, there’s another season upon us — and it’s not exactly the festive sort. It’s flu season. 

Flu diagnoses have already begun to crop up (ICYMI, Kylie Jenner was recently hospitalized for “severe flu-like symptoms”) and the Centers for Disease Control and Prevention (CDC) and the National Foundation for Infectious Diseases (NFID) just kicked off their annual flu vaccine campaign, sharing updated stats about the flu shot and onset of the 2019 flu season.

Among them was the fact that more than half of American adults remain unprotected from the flu each season; last year, adults 18 to 49 years old were the least vaccinated subgroup at just 35 percent. And that’s despite super-scary numbers from the previous flu season: A record-breaking 900,000 Americans were hospitalized and more than 80,000 died from the flu in 2017, according to a 2018 report by the National Foundation for Infectious Diseases.

RELATED: How to Tell If You Have a Cold or the Flu

Still need some convincing to go out and get a flu shot (or just want to clear up some common flu shot myths)? We’ve got you covered. Here’s everything you need to know about this year’s flu shot, including what’s changed (hint: it’s better!), who should get vaccinated, flu shot side effects, and where to go to get your flu shot. 

VIDEO: Kylie Jenner Has Reportedly Been Hospitalized

So, How Does a Flu Shot Work?

If you’ve always wondered how the flu shot works, here's the gist: Depending on the type of vaccine you receive, it will contain either "dead" strains of the flu virus, or weakened "live" viruses.

"Injectable flu vaccines are made from either inactivated or partial flu virus and are meant to activate your immune system so that you develop antibodies against the flu virus," explains Nate Favini, M.D., a doctor and the medical lead at Forward, a preventive primary care service. In other words, it triggers your body's natural defense mechanism to be able to fight the actual flu when the time comes. 

When Is Flu Season?

OK, so there isn’t really a clear cut answer for this one. The CDC notes that flu season’s timing varies from year to year — it can peak from as early as October to as late as May — and is therefore rather unpredictable. 

The 2018-2019 flu season was record-breaking in duration, with flu activity remaining elevated for 21 weeks, according to the CDC. The U.S. had two different waves of flu, the first caused by H1N1 viruses and the second caused by H3N2 viruses. 

The CDC has not released official data on the 2019-2020 flu season, but, starting in late fall, the organization will release weekly forecasts that predict the impact of the flu.

When Is the Best Time to Get a Flu Shot?

Since flu season is a bit of a moving target, it can also be tough to predict when to get the flu shot. But that doesn’t mean experts don’t try. This year, the CDC recommends that everyone get their flu shot by the end of October.

While you may assume the earlier the better, some experts suggest holding off until later in the month. "Late October is probably the ideal time to get the shot, since February is the most common month for flu outbreaks, and immunity to the flu wanes about 10 percent each month following vaccination," explains David Cutler, M.D., a family medicine physician at Providence Saint John’s Health Center. (For this reason, it’s usually not advisable to get your flu shot as early as August, even if it is available.)

One exception? If you have upcoming travel plans to the tropics (where flu activity occurs throughout the year) or to a destination currently experiencing an outbreak, then it's best to get your flu shot stat, according to the CDC.

RELATED: When Is It Too Late to Get a Flu Shot?

Has the Flu Vaccine Changed This Year? 

This year’s vaccine has been updated, just as it is every year when the CDC reviews and makes changes to the vaccine to accommodate the ever-changing nature of the flu virus.

One major improvement? The regular dose and recombinant flu vaccine (the only egg-free vaccine) will now protect against more strains than last year. 

“Though some flu shots protect against three strains of the flu (called trivalent vaccines) — two strains of influenza A and one strain of influenza B — most of the vaccines on the market this year are quadrivalent (meaning they protect against four strains of the flu), covering two influenza A strains and two influenza B strains,” says Dr. Favini. 

Who Needs the Flu Vaccine? 

The short answer: everyone who is six months or older. There are only a few rare exceptions, according to the CDC, including if you have an allergy to the flu vaccine or any ingredients included in it. Luckily, this is extremely rare, Dr. Favini says, “with only about one in 1 million people having a severe allergic reaction after receiving a vaccine.”

If you are pregnant or have a compromised immune system, it doesn't mean the flu shot is off the table, but it does mean you'll want to make sure you're sticking to a "killed" vaccine — found in the traditional flu shot. 

You’ll also want to chat with your doctor before getting the vaccine if you have ever had Guillain-Barré Syndrome, a rare but serious autoimmune disorder. 

What About the Nasal Spray Flu Vaccine?

In addition to the traditional flu shot, there's another option available for healthy, non-pregnant people who are 2 to 49 years old: The nasal spray flu vaccine, which is administered just like an allergy nasal spray. Although it's been around for a few years, the CDC gave its seal of approval last year as an effective alternative to the traditional flu shot for the needle averse.

Since it's a "live" rather than a "killed" vaccine, it should also be avoided by anyone who is severely ill, has an immune disorder, or who cares for someone who is severely immunocompromised. You should also take precautions if you have asthma or any other underlying health condition, such as lung, kidney, or heart disease. 

The CDC notes that, while age and health status are a factor in deciding the type of vaccine an individual should get, the important thing is simply getting one in the first place. 

Do I Really Need to Get a Flu Shot Every Year?

No matter the flu shot that ends up working best for you and your needs, it’s important to make getting one an annual habit. That's because the flu virus morphs and changes every year, meaning last year’s shot might do absolutely nothing to protect you from the straing of flu that sweeps through your office this year.

But there's another reason, too. The vaccine might have a cumulative effect.

In one 2017 study, researchers found that the flu shot’s effectiveness may be influenced by vaccines from prior seasons. And in a 2018 study published in the Canadian Medical Association Journal, researchers found that people 65 and older — one of the most vulnerable populations to the effects of influenza — who had repeat vaccines were twice as able to fight the most severe complications related to the flu, including death.

Should I Still Get the Flu Shot If I'm Sick? 

You’ve probably heard that if you’re feeling less than 100 you should skip the flu shot, but this is one major flu shot myth. 

“If you have a mild cold or are a little under the weather, you can still get the shot,” Dr. Favini says. 

The exception: If you also have a fever. “The concern is that your immune response to the vaccine might not be as strong as needed to boost your immunity, because you’re already fighting another infection,” he says. “In those cases, it’s best to wait until you’re feeling better before getting the shot.”

Are There Flu Shot Side Effects?

It’s true: You might experience some side effects as a result of getting the flu shot, which can include soreness, redness, and/or swelling in the area where the shot was administered, headache, fever, nausea, and muscle aches.

While these symptoms will resolve on their own, the CDC notes that you should seek emergency care if you begin to experience any of the following: a high fever, difficulty breathing, wheezing, swelling around the eyes or lips, hives, paleness, weakness, dizziness and/or a rapid heartbeat. 

Overall, flu shot side effects are generally mild — and no, it's not possible for the shot to 'give you the flu.' “It’s common to experience mild aches, fever, or headache after getting the shot, but that’s considerably better than getting the actual flu," Dr. Favini emphasizes.

How Effective Is the Flu Shot Anyway?

Getting the flu shot can reduce your risk of getting the flu by 30 to 60 percent, depending on the strains that are circulating during a season. In one 2018 study, researchers discovered that from 2012 to 2015, adults who got the flu shot saw a 37 percent reduced risk of being admitted to the hospital with the flu.

It's true that a person's age and health can impact the overall effectiveness of the vaccine — and it isn't a sure-fire guarantee you won’t get the flu. That's because it’s tough to create a vaccine well-matched to the exact strains of the virus that will circulate during a specific flu season. 

But just because the flu vaccine isn’t 100 percent effective doesn’t mean you should skip it — it's simply the best way to protect yourself and everyone around you. 

“Getting the flu shot is the smart thing to do for your own health — many people don’t realize that even healthy, young adults can get sick to the point of hospitalization or even death,” Dr. Favini says. “Beyond that, getting vaccinated contributes to what’s called 'herd immunity' — the more people that get vaccinated, the less likely a severe epidemic becomes.”

He added: “This helps protect more vulnerable people like young babies who can’t get the flu shot and seniors who are more likely to become very ill with the flu. Your shot could save the life of someone you know.”

So, Where Can I Get a Flu Shot?

Convinced? Good. 

“The flu vaccine for the winter 2019-2020 season is available now at your primary care physician’s office, local pharmacies, and perhaps through your work or other community vaccine programs,” Dr. Cutler says. 

It’s true: You can pop into your local Walgreens or CVS while you’re grabbing toilet paper and cross it off the to-do list. Check out the CDC’s flu vaccine finder where all you have to do is type in your zip code for a list of places that offer the flu shot in your area.