CDC recommendation against nasal spray vaccine decreased flu vaccine rates in children

By Liz Meszaros, MDLinx
Published August 27, 2017

Key Takeaways

For the 2016-2017 flu season, influenza vaccination rates in children may have decreased as a result of a recommendation by the Centers for Disease Control and Prevention (CDC) that the nasal spray version of the vaccine not be used, according to researchers from Penn State College of Medicine, Hershey, PA, who published their results in Vaccine.

The nasal spray vaccine was often preferred by parents as a painless and convenient option, and initially, several studies demonstrated that it was more effective than the injectable version in children.

Additional research in 2016, however, showed that the nasal spray vaccine was less effective than the injectable form in preventing the H1N1 influenza strain. Following this, the CDC reversed its stance, recommending against the nasal spray for the 2016-2017 influenza season.

“We wanted to understand what happened to vaccination rates with this new recommendation,” said study co-author Ben Fogel, MD, MPH, assistant professor of pediatrics, Penn State College of Medicine, and medical director, Penn State Pediatric Primary Care, Hershey, PA. “Would this recommendation against nasal spray vaccine shake people’s confidence in the influenza vaccine in general or make them less likely to get it because they have to get a shot?”

For the study, Dr. Fogel and Steven Hicks, MD, PhD, assistant professor of pediatrics, Penn State College of Medicine, retrospectively assessed total vaccination rates in 9,591 patients from Penn State Pediatrics, aged 2 to 17 years during the 2014-2015, 2015-2016, and 2016-2017 influenza seasons. They also assessed the percentage of children vaccinated against influenza during subsequent seasons.

They found that when the option of the nasal spray vaccine was not given (2016-2017), total influenza vaccination rates were 1.6% lower compared with rates in 2015-2016, when the nasal spray option was available. Early vaccination rates in the 2016-2017 season were significantly higher compared with rates in 2015-2016 (24.7% vs 22.8%, respectively; P=0.004), but end-of-season rates were lower (50.4% vs 52.0%; P=0.03). Why these rates started high and but then decreased are not known.

“We worried that there was going to be a huge drop off in vaccination rates without the nasal spray available,” said Dr. Fogel. “We saw a drop off but I would not call it huge, which is reassuring.”

They also found that black and Hispanic children, those aged 13 to 17 years, and those with public insurance were less likely to be vaccinated again in 2016-2017.

“One thing we found that we didn’t expect to see was a large percentage of people who switched their vaccine preference from one year to the next, meaning that one year they didn’t get the influenza vaccine and the next year they did or vice versa,” said Dr. Fogel. “Our data showed that 35% to 50% of people change their minds about getting the influenza vaccine from one year to the next.”

Their findings suggest that the highest predictor of vaccination was not previous vaccination, as was previously shown.

“Instead, it seems that people may not be either vehemently pro-flu vaccine or anti-flu vaccine; rather if it’s convenient, they’ll get the vaccine, and if it’s not convenient, they won’t go out of their way to get it,” said Dr. Fogel, who plans to study a follow-up intervention to improve vaccination rates in those who do not feel strongly one way or the other.

“We plan to call patients who already have appointments scheduled during flu season and see if they can bring in a sibling at the same time to make that flu vaccine happen. I’m excited to see if we can drive vaccination rates up,” he concluded.

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