Related Experiment Video
Updated: Jun 19, 2025
An Optimized Hemagglutination Inhibition HI Assay to Quantify Influenza-specific Antibody Titers
Published on: December 1, 2017
Effect of Childcare Influenza Vaccine Requirement on Vaccination Rates, New York City, 2012-2020
Amy E Metroka1,2, Vikki Papadouka1,2, Alexandra Ternier1
1Bureau of Immunization, New York City Department of Health and Mental Hygiene, Queens, NY, USA.
Insights
New York City's childcare influenza vaccine requirement boosted vaccination rates in young children. Reinstatement of the policy further increased immunization coverage, demonstrating the effectiveness of vaccine mandates.
Area of Science:
- Public Health
- Epidemiology
- Vaccinology
Background:
- Influenza vaccination is crucial for preventing severe illness in children.
- Childcare settings are key environments for monitoring and improving vaccination rates.
- Vaccine requirements are a public health strategy to increase immunization coverage.
Purpose of the Study:
- To evaluate the impact of New York City's childcare influenza vaccine requirement on vaccination rates.
- To assess changes in influenza vaccination coverage among children aged 6-59 months during different phases of the policy (implementation, suspension, reinstatement).
Main Methods:
- Analysis of influenza vaccination rates in children aged 6-59 months over 8 influenza seasons (2012-2020).
- Comparison of vaccination rates before, during, after suspension, and after reinstatement of the childcare vaccine requirement.
- Difference-in-differences analysis comparing age groups affected by the requirement and a control group (children aged 5-8 years).
Main Results:
- The requirement initially increased vaccination rates by 3.7 percentage points, with the most significant impact on 4-year-olds.
- Suspension of the policy led to a decline in vaccination rates.
- Reinstatement of the requirement resulted in a substantial increase of 10.7 percentage points overall, and 22.2 percentage points for 4-year-olds.
Conclusions:
- The New York City influenza vaccine requirement effectively improved vaccination rates in preschool-aged children.
- The findings support the use of vaccine requirements as a strategy to enhance public health immunization levels.
Objectives:
In 2014, New York City initiated a childcare influenza vaccine requirement to increase influenza vaccination rates among children aged 6-59 months attending city-regulated childcare, including prekindergarten. We evaluated the requirement's effect on vaccination rates in childcare-aged children in New York City.
Methods:
We examined influenza vaccination rates in children aged 6-59 months and by age groups of 1, 2, 3, and 4 years for 8 influenza seasons (2012-2013 through 2019-2020), representing 2 seasons before the requirement, 2 seasons during the requirement, 2 seasons after its suspension, and 2 seasons after its reinstatement. We also assessed rates in a comparison group of children aged 5-8 years. We performed a difference-in-differences analysis to compare rate differences in age groups when the requirement was and was not in effect. We considered P < .05 as significant based on the Wald χ2 test.
Results:
Influenza vaccination rates among children aged 6-59 months increased 3.7 percentage points (from 47.7% to 51.4%) by the requirement's second year and declined 6.7 percentage points to 44.7% after suspension. After reinstatement, rates increased 10.7 percentage points to 55.4%. Rate changes were most pronounced among 4-year-olds, increasing 12.7 percentage points (from 45.3% to 58.0%) by the requirement's second year, declining 14.1 percentage points to 43.9% after suspension, and increasing 22.2 percentage points to 66.1% after reinstatement. In the comparison group, rates increased 4.9 percentage points (from 36.5% to 41.4%) after reinstatement. Rates increased significantly among 4-year-olds before versus at the initial requirement and decreased significantly after suspension. After reinstatement, rates increased significantly among all groups except 1-year-olds.
Conclusion:
The New York City influenza vaccine requirement improved influenza vaccination rates among preschool-aged children, adding to the evidence base showing that vaccine requirements raise vaccination rates.
