Vaccine effectiveness and severity of current and prior seasons of influenza have demonstrated no association with vaccination rate in children, according to a study published in JAMA Pediatrics.

Compared with other pediatric and adolescent vaccines, the influenza vaccination rate remains low in children. Although many reasons may affect whether a child is vaccinated, the extent to which the severity of the current and prior year’s vaccine effectiveness affects the vaccination rate has not previously been studied. If severity and vaccine effectiveness influence the vaccination rate for influenza, it is important to understand the mechanics to relay this information to parents and effect an increase in these rates. Therefore, researchers examined the associations of seasonal influenza severity, as well as current and prior year’s vaccine effectiveness with yearly vaccination rates within age groups, using publicly available data.

Data were extracted from the Centers for Disease Control and Prevention (CDC) for the 2010 to 2017 seasons, which included: influenza vaccination rates per age group (6-23 months, 2-4 years, 5-12 years, and 13-17 years), yearly CDC influenza severity designations for pediatric patients (low, moderate, high, and very high), and vaccine effectiveness. The associations of vaccination rate with current and prior year’s vaccine effectiveness and season influenza were assessed using negative binomial models and were adjusted for age groups and linear and quadratic terms of years.

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Data showed that vaccine effectiveness varied across the years studied, ranging from 19% to 60%. Vaccination rate did not show a significant association with the current or prior year’s vaccine effectiveness. However, after a particularly low rate of vaccine effectiveness (19%) in 2014, there was a slight decline in vaccination rates in 2015. Severity of the current influenza season was also not associated with vaccination rates across age groups and years: high/very high severity vs low severity had a rate ratio (RR) of 1.02 (P =.63), and moderate severity vs low severity had a RR of 1.03 (P =.21). Similarly, prior season severity was not associated with vaccination rates.


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The overall trend of influenza vaccination rates across age groups has been declining over the recent years and could be a reflection of the antivaccine movement. Furthermore, hesitancy in the influenza vaccine may be a result of a several compounding issues, including misperception of influenza risk and severity and a lack of confidence in vaccine effectiveness and safety, as well as healthcare authorities. Overall, the study authors concluded that, “Further research understanding what factors affect vaccination decisions that could be targeted in future interventions may be warranted.”

Reference

Abraham C, Chen Q, Fan W, Stockwell MS. Association of seasonal severity and vaccine effectiveness with influenza vaccination rates in children. JAMA Pediatrics. doi:10.1001/jamapediatrics.2019.4221