The impact of increasing vaccination coverage in children on symptomatic
influenza cases using the Framework for Reconstructing Epidemiological
Dynamics (FRED)
Abstract
Background: The availability of self- or caregiver-administered
nasal spray live attenuated influenza vaccine (LAIV) raises the
potential for increased influenza vaccine uptake and increased vaccine
effectiveness (VE) via mucosal immunity. Direct and indirect benefits of
increased uptake among school-age children (decreased influenza cases
and hospitalizations) may be realized across the age spectrum. We used
an agent-based model, the Framework for Reproducing Epidemiological
Dynamics (FRED) to determine the extent to which increased vaccination
of children might affect overall influenza epidemiology.
Methods: FRED uses a population based on the US census and
accounts for individual characteristics to estimate the effect of
changes in parameters including vaccine uptake on outcomes. We modeled
increases in vaccine uptake and VE among school-age children 5-17 years
on influenza cases and hospitalizations by age group. Results:
Increasing vaccination rates in school-aged children by 5%-15%
decreased their symptomatic influenza cases by 3.2%-10.9%, and over
all age groups by 3.3%-11.6%, corresponding to an estimated annual
reduction in cases among school-age children of 522,867-1,810,170 and
1,394,687-4,945,952 overall. Fewer days of missed school by children and
work by caregivers could offset those required to increase vaccination
coverage. Annual U.S. hospitalizations could decrease by as much as
49,977, with the greatest impact (23,258) in those ages 65 years and
over. If childhood influenza VE increased only 5%, the attendant
improvement in cases would exceed that of a 5%-15% increase in
vaccination coverage. Conclusion: The opportunity to increase
vaccination coverage in school-age children using LAIV can have a
positive impact across all ages.