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It’s officially fall in the US, which means it’s time for cozy sweaters, pumpkin-flavored everything, and...your seasonal influenza vaccine. Given that last year's flu season was one of the deadliest in the last 40 years — an estimated 80,000 people died, including 180 children — it's important to get a flu shot as soon as possible. The Centers for Disease Control and Prevention recommends that everyone who is 6 months or older get vaccinated by the end of October. And this year, it doesn't even necessarily have to be a shot. The nasal spray vaccine is back this flu season — so, needle-phobes, rejoice. Keep in mind that the flu shot isn't perfect. Even if you get vaccinated, you can still get the flu. But your symptoms should be less severe, and you are less likely to be hospitalized or die of the flu. To answer all of your flu shot questions, we spoke with Dr. Lisa Maragakis, senior director of infection prevention at the Johns Hopkins Health System in Baltimore, Maryland, and included advice from a panel of public health experts at the 2018 CDC and National Foundation for Infectious Diseases (NFID) flu vaccination conference.

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Which type of flu vaccine should I get? There are several different types of flu vaccine available — which one you get will depend on your age and health. The shot is either trivalent, meaning it protects against three strains of the virus, or quadrivalent, meaning it protects against four. They are both effective. The viruses are killed or attenuated (weakened), so they won't make you sick, but they will allow your body to develop antibodies so you can fight off the actual flu. You may have mild symptoms as your body responds to the vaccine, but these are typically short-term side effects. The flu shot will not give you the flu. Here's the CDC's list of vaccines available for the 2018–2019 season. Talk to your health care provider to find out which vaccine is right for you. * Standard dose flu shots: meant for people between 6 months and 65 years of age, including pregnant women. * High-dose shots (Fluzone): meant for people over 65. * Shots made with adjuvant (Fluad): meant for people over 65. * Cell-based flu vaccine (Flucelvax): These are made in animal cells grown in a laboratory instead of in eggs, like other flu vaccines. This vaccine could be beneficial for people who are allergic to eggs. * Recombinant vaccine (Flublok): another egg-free alternative for people over 18. * Live attenuated influenza vaccine or nasal spray (FluMist): meant for people between 2 and 49 years of age who aren't pregnant. FluMist provides the same protection as an injectable shot, but it isn't meant for everyone. “It's a live-virus vaccine; it's attenuated so it won't give you the flu, but people who have suppressed immune systems shouldn't get that type,” Maragakis told BuzzFeed News. Some groups shouldn’t get the flu vaccine at all. These include babies under 6 months and people with a life-threatening allergy to an ingredient in the vaccine.

Is it possible to get vaccinated “too early”? The CDC is recommending you get your flu shot by the end of October. Even if it’s still warm outside and nobody around you seems to have the flu, it’s still a good idea to get vaccinated. It takes about two weeks for your immune system to respond to the shot and make antibodies so you’re protected from the flu, Maragakis said. Considering that flu season starts in November, it's definitely not “too early” to get your shot in late September or October. The vaccine will help protect you for the duration of flu season, which typically goes until March — but it only lasts for one season, so you need to get one every year. What if you don't get vaccinated by the end of October? “It's still worthwhile to get a vaccine during flu season — even in December and well into the peak of the season. ... It’s not ideal, but it’s better than being unvaccinated,” Maragakis said.

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Where do I get the shot and how much will it cost me? You can get a flu shot at your doctor’s office, pharmacy, certain supermarkets, college health centers, and local or state health departments. Use the CDC's Flu Vaccine Finder to find a location near you. If you need a specific type of vaccine, call ahead to make sure that location has it in stock. In many cases the flu vaccine is free, but it depends on your insurance coverage, age, and other factors. Under the Affordable Care Act, insurance plans are required to cover the flu shot with no copay — but check with your insurance beforehand, because some plans only cover the shot if you get it at a certain location. Military insurance covers vaccines for members and their dependents. Medicare covers one flu shot each season, and Medicaid covers flu shots for children and some adults — contact your state’s Medicaid office to find out if you’re covered. If you don’t have insurance and can’t afford the out-of-pocket cost (which is anywhere between $20 and $70 or higher depending on the type of vaccine), there are still ways to get the shot for free or low-cost. The Vaccines for Children Program covers vaccines for children under 19. Many pharmacies offer coupons; just check their website or call and ask. Finally, your state health department can help you find out where to get a free or low-cost flu shot.

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I heard the flu shot didn't work well last year. What happened? Last year, the flu vaccine included two influenza A viruses, H1N1 and H3N2, and an influenza B virus. The predominant circulating strain (H3N2) was not particularly well matched with the strain included in the vaccine, Maragakis explained, so it had a lower effectiveness of about 25%. That said, the vaccine effectiveness was in the ~50–65% range for the other strains. The overall vaccine effectiveness was 40%, which means the vaccine reduced a person’s risk of having to seek medical care for the flu by 40%, according to the CDC. The flu shot is, at best, about 60% effective. The effectiveness varies each year based on how well the strains in the vaccine match the ones that circulate in the population. Scientists predict which strains will pop up during flu season in the US by looking at surveillance data from other parts of the world at the start of the year, because it takes at least 6 months to produce large quantities of the flu vaccine. Sometimes, these predictions are off and one of the strains that circulates isn't included in the vaccine, said Maragakis. The flu also mutates constantly, so the circulating strains can change between the time scientists make a prediction and when the flu vaccine is ready. The good news? The flu vaccine includes three to four strains, so even if there’s a mismatch it will still protect against other viruses, Maragakis noted. Some protection is better than none.

But wait — isn't this year's flu season supposed to be mild because last winter’s was so bad? Influenza activity does vary year to year; however, the experts said it’s still too early to tell whether this year’s flu season will be mild. Last year, there were some prior indications that the US was in for a bad season, Maragakis said, based on what was going on in other parts of the world, particularly in Australia. But this isn't a perfect predictor and you should still get a flu shot regardless. “By the time we figure out if a flu season is mild or not, the damage has been done. ... Everyone should look at every season as if it will be a bad season, and everyone should get vaccinated,” Surgeon General Dr. Jerome Adams said at the CDC-NFID conference.

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Last year I got the vaccine and I still got the flu — what gives? Yes, it’s possible to still get the flu even after receiving the vaccine — as we mentioned, there’s no 100% guarantee. However, if this does happen, you’re likely to have a less severe illness. “The flu shot boosts your body’s ability to fight infection, so you may get the flu but have milder symptoms, avoid hospitalization, and avoid death,” said Maragakis. So you can benefit from the shot even if you get the flu. Another reason this happens is because people may get infected right before receiving the vaccine, when they don’t have symptoms yet. The flu has an incubation period of one to four days, so it's possible to get the shot when you already have the flu and don’t know it. In this case, the vaccine could still protect you against other strains that circulate later in the season.

The flu isn’t that serious, and if I get it and recover, I’ll get some immune protection, right? Getting the flu is not better than getting the flu shot. The flu is deadly — and it can kill healthy adults. Even if you do recover, there are vulnerable people who won’t. Those at highest risk for hospitalizations or death from the flu are the elderly, children, and people with suppressed immune systems or underlying medical conditions such as diabetes or heart disease. In some people, flu-related complications can persist and seriously impact their lives even after they recover, Dr. William Schaffner, medical director at the NFID, said at the conference. There are two main post-flu problems. First, the flu can trigger a systemic inflammatory reaction that continues beyond the resolution of illness. The lingering inflammation can involve blood vessels in the heart and brain, Schaffner said, so there is an increased risk of heart attack and stroke during the two to four weeks after a person recovers from the flu. Second, people who have certain disabilities or preexisting conditions may never completely recover or return to their pre-flu functional level. “Flu can knock down the first domino of progressive decline, progressive disability,” Schaffner said.

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My kid is healthy — is the flu shot really necessary? According to Schaffner, about 50% of the children who were hospitalized had underlying conditions that predisposed them to flu-related complications — which means the other half were healthy. But there was one common theme among the children who died last winter. About 80% of deaths occurred in children who had not received a flu vaccination, according to the CDC. Last flu season, there was a 2.2% decrease in vaccinations among children aged 6 months to 4 years. These young children are especially vulnerable, and seeing a decline in vaccination in this age group is worrisome, Adams said. So even if your kid is healthy, they still need a flu shot — not only to protect themselves, but also their classmates, friends, elderly family members, etc.

Can I get the flu shot if I'm pregnant? Yes, yes, yes. The CDC recommends that all pregnant women get a flu vaccine during any trimester. Pregnant women can pass the antibodies to the baby, so they are protected for the first 6 months of life, when they are too young to get a flu vaccine. Pregnant women are particularly vulnerable, even if they are healthy. Pregnancy affects the immune system and decreases lung volume, so it’s harder to clear a respiratory infection. Pregnant women who get the flu generally do very poorly, Dr. Laura Riley, chair of the department of obstetrics and gynecology at Weill Cornell Medicine, said at the CDC-NFID conference. When pregnant women get the flu, it can also harm the pregnancy and increase the risk of birth defects and premature delivery, Riley said. “Last year about 49% of pregnant women got the flu vaccine — it really should be 80-plus percent. ... We really need to do a much better job,” Riley said.

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