The Nasal Spray Flu Vaccine May Be Less Effective Than the Shot—so Should You Get It?
After a two-year hiatus, the Centers for Disease Control and Prevention (CDC) has again included the FluMist nasal spray flu vaccine in its annual flu vaccine recommendations. The CDC now says, “[N]o preference is expressed for any one vaccine type.” For the 2018-2019 season, people now have the option of getting the traditional flu shot or a nasal spray.
Experts will tell you that getting vaccinated against this year’s circulating flu strains is the best way to stay healthy. But in any given year, the effectiveness of the vaccine–injection or spray–is always a gamble. Some may feel the spray may be a better bet than the shot, but others, like the American Academy of Pediatrics (AAP), for instance, are still leaning toward the injection.
The flu strains that circulate change every year (and each year there are several), so vaccine developers base their formulas on their best predictions of which strains will be around in the coming season (often based on what’s being seen in the Southern Hemisphere). In a good year, a vaccine will be at least 50 or 60% effective. Last year, the shot was not a good match, offering protection only 36% of the time.
The nasal spray performed poorly for three seasons in a row, from 2013 to 2016, especially among kids aged 2 through 17. That’s why both the CDC and the AAP stopped recommending the nasal spray vaccine for the 2016-2017 and 2017-2018 flu seasons. (The nasal spray was still licensed by the Food and Drug Administration during that time).
“Data from the three previous seasons (2013 to 2016) showed that the nasal spray wasn’t as effective as the shot, especially against the influenza A H1N1 virus,” says Kristen Nordlund, a spokesperson for the CDC.
New research analyzing previous flu vaccine studies adds to these findings. In the study, published in Pediatrics in January, the nasal spray flu vaccine was found to be less effective at warding off influenza than flu shots between 2013 and 2016.
“For a couple of years there was data that the efficacy against one influenza strain–H1N1–wasn’t performing as well as the injection,” adds David Cennimo, MD, assistant professor in medicine and pediatrics at Rutgers New Jersey Medical School in Newark. “It turns out the virus they were using in constructing the vaccine wasn’t that good at making your body form antibodies.”
So why is this year different? “The manufacturer of the nasal spray has included a new influenza H1N1 virus in the vaccine, and data from abroad may suggest this will result in improved effectiveness,” says the CDC’s Nordlund.
Both the spray and injection forms of the influenza vaccine work in similar ways. The traditional flu shot uses dead viruses to stimulate your body to produce antibodies, or proteins, to fight off influenza. It takes about two weeks for the antibodies to ramp up. Then, hopefully, if you’re exposed to the actual flu, your body has the wherewithal to fight it off, and you make it through flu season without actually getting sick–or at least not getting that sick.
The nasal spray vaccine also teaches your body to produce flu-fighting antibodies, but it uses a live virus, albeit a very weakened one. The vaccine is sprayed directly into your nose, where the virus strains reproduce. In fact, they’re created to replicate only at the cooler temperatures found in your nose, as opposed to warmer areas like your lungs. You won’t get the actual flu.
Of course, only time will tell how effective the nasal spray proves to be. “Right now, we don’t have data showing how well it works in real life because it’s off-market," says Dr. Cennimo. "The science and the limited trial data show it should work as well as injections, but to be really accurate, we’re not going to know until the end of this [flu season].”
The CDC and the AAP differ slightly in their recommendations about the nasal spray vaccine. In a statement, the AAP says all children over the age of six months should get the shot, and that the nasal spray should be reserved for cases when a child "wouldn't get vaccinated otherwise–for example, if your child is absolutely refusing the shot but is willing to get the nasal spray or if your doctor is out of the flu shot but has the nasal spray available.”
Still, many experts believe the shot remains the way to go.
“I think that the shot is still preferred,” says Jean Moorjani, MD, a pediatric hospitalist with Arnold Palmer Hospital for Children in Orlando. “But if you have a child that says there is absolutely no way I am getting a shot ... maybe getting the nasal spray is better than nothing.”
“If someone is willing to get the injection they should just get that,” adds Dr. Cennimo. “If they meet the criteria for the spray and would prefer that, it is acceptable.”
The nasal spray is approved for individuals aged 2 to 49, while the shot is approved for all individuals starting at six months. The nasal spray should not be given to pregnant women or to individuals with certain medical conditions. Check with your health care provider to make sure whichever vaccine you choose is safe for you.
The bottom line? Get vaccinated–and get used to washing your hands.
“Like many of the viruses that will circulate this winter, the influenza virus is contracted through contact, so it really is [about] washing your hands and trying to prevent infecting others,” says Dr. Cennimo. “If you’re sick, stay at home. Don’t go in and be a hero at work and infect everybody else. Cover your cough and your sneeze. If soap and water aren’t available, then used an alcohol-based hand sanitizer.”
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