Vaccine coverage estimation using a computerized vaccination registry with potential underreporting and a...

Area of Science:

• Epidemiology
• Biostatistics
• Vaccinology

Background:

• Computerized vaccine registries are crucial for monitoring immunization programs.
• Underreporting in registries can lead to inaccurate vaccine coverage estimates.
• Seroprevalence studies offer an alternative measure of population immunity.

Purpose of the Study:

• To develop and illustrate a novel method for estimating vaccine coverage using both registry data and seroprevalence.
• To quantify the underreporting rate in a vaccine registry for meningococcal C conjugate vaccine (MCCV).
• To assess MCCV uptake in different age groups.

Main Methods:

• A Bayesian model was developed to integrate data from a vaccine registry (SIV) and a seroprevalence study.
• 1430 subjects aged 3-29 years were analyzed for MCCV status and seroprotection levels.
• Subjects with unregistered MCCV were categorized based on other vaccine records.

Main Results:

• Seroprotection levels were similar between registered and unregistered MCCV subjects, indicating substantial underreporting.
• Estimated MCCV coverage exceeded 80% in most age groups, but was 67.6% for those >22 years.
• Underreporting rates varied by age group, ranging from 23.5% to 73.4% for the 2002 catch-up campaign.

Conclusions:

• The Bayesian model provides a more accurate estimation of vaccine uptake compared to registry data alone.
• The study quantified significant underreporting in the SIV registry, particularly for vaccinations during the 2002 catch-up campaign.
• This methodology is valuable for improving vaccine coverage assessments and understanding registry limitations.