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Unavailability of LAIV may decrease pediatric vaccination rates

Ben Fogel

Vaccination rates were lower among children in the 2016 to 2017 influenza season when compared with the 2015 to 2016 season, according to recent findings. These results coincide with the CDC Advisory Committee on Immunization Practices recommending against using live-attenuated influenza vaccine in June 2016, suggesting the unavailability of this vaccine may impact vaccine uptake in pediatric patients.

“We saw a 1.6% decrease in end of season influenza vaccination rates after the live-attenuated vaccine was no longer recommended by the CDC. This difference is small but statistically significant,” Ben Fogel, MD, MPH, assistant professor of pediatrics, medical director of Hope Drive Pediatrics and associate director of quality for outpatient pediatrics at Penn State College of Medicine, told Healio Family Medicine. “The CDC makes evidence-based recommendations about the influenza vaccine every year. It is important for researchers to study the effects of these recommendations on real-world outcomes.”

As a nasal spray, the live-attenuated influenza vaccine (LAIV) seemed a less painful and more convenient option for young children; however, later research found the nasal spray was less effective than the injectable vaccine in preventing the H1N1 strain of influenza, which prompted the 2016 CDC Advisory Committee on Immunization Practices recommendation that LAIV should not be used. Although there have been concerns that abandoning the vaccine could reduce influenza vaccination among children, a CDC official said earlier this year that vaccination coverage had changed little after the reversal.

To understand the impact of this recommendation on the pediatric population, Fogel and colleagues compared early season (before November 1) and end-of-season (before March 1) vaccination rates in the 2015 to 2016 influenza season with rates in the 2016 to 2017 season. They examined the vaccination rates in 9,591 Penn State Pediatrics patients aged 2 to 17 years, and recorded the percentage of children who received flu vaccine in subsequent seasons.

The results showed that early vaccination rates in the absence of LAIV in the 2016 to 2017 season were significantly higher (24.7% vs. 22.8%; P = .004), but end-of-season influenza vaccination rates were lower when compared with the 2015 to 2016 season (50.4% vs. 52%; P = .03). Additionally, the researchers found that the revaccination rates were even lower in children who had received the nasal spray in the year before.

“One thing we found that we didn’t expect was a large percentage of people who switched their vaccine preference from one year to the next,” Fogel said. “Our data showed that 35% to 50% of people changed their minds about getting the influenza vaccine from one year to the next. This is interesting because previous studies on vaccination show that the single highest predictor of getting vaccinated is if that person got vaccinated the year before.”

Children who received inactivated influenza vaccine in the 2015 to 2016 season were more likely to receive another vaccination in the 2016 to 2017 season (OR = 1.32; 95% CI, 1.15-1.52) compared with those who had received LAIV in the 2015 to 2016 season.

“These results suggest that patients and families do not just fall into the ‘pro flu vaccination’ or ‘anti flu vaccination’ camps; there is a third grouping of people who will get vaccinated if it is convenient, but won’t necessarily go out of their way to get it,” Fogel said. “This knowledge could inform future quality improvement efforts to increase influenza vaccination rates, as well as conversations about the influenza vaccine between primary care physicians and their patients.” – by Savannah Demko

Disclosures: The researchers report no relevant financial disclosures.