OBJECTIVE: Incomplete and delayed vaccination is a barrier to individual and population protection from vaccine-preventable diseases. We aimed to assess visit frequency and pattern in relation to vaccination status in a Swiss cohort of 2-year-old children in order to review opportunities for completion of scheduled immunizations.
METHOD: A retrospective dynamic cohort study design involving children insured with a single health insurer in Switzerland was chosen. Time-to-event analysis was used to evaluate timing of defined immunizations of interest from submitted invoices. Diphtheria, tetanus, acellular pertussis (DTaP) and measles, mumps and rubella (MMR) immunizations administered to children registered with this health insurer were assessed. The specified vaccines are recommended at 2, 4, 6 and 15-24 months, and 12 and 15-24 months of age, respectively.
RESULTS: 21,588 children born between January 1st, 2006 and June 30th, 2008 and registered with the health insurer from no later than 4 weeks of age were included. Only 40.9% of the cohort was up-to-date for both vaccines (DTaP and MMR) at 2 years of age. The average number of visits made during up to 2 years of age was 14.7 (95% CI: 15.9-16.3). Less than 5% of children made fewer than 5 visits, the minimum number required to complete all recommended immunizations by 2 years of age. Although number of visits varied by final vaccination status, more than 90% of the cohort made sufficient visits to complete the specified courses, even when contraindications were assumed to be present at up to half the visits.
CONCLUSION: Swiss children who are not fully immunized at 2 years of age make fewer visits to ambulatory health care up to that age, but they have more than sufficient opportunities to complete immunizations as scheduled. Ambulatory healthcare providers in Switzerland have ample opportunity to promote and administer vaccinations in a timely manner.