Summer vacation and vaccination: Seasonal variation in uptake of adolescent vaccines

Background. Identifying cycles of variation in adolescent vaccination would highlight periods when vaccine promotion programs could be particularly effective. We hypothesized that uptake of recommended adolescent vaccines would vary cyclically across years, with vaccination concentrated in the summer months.

Methods. Data came from 72,931 participants in the 2008-2012 versions of the National Immunization Survey-Teen, which collects nationally-representative, provider-verified data about vaccination among 13- to 17-year-old adolescents. Using administration dates of each recommended adolescent vaccine (tetanus, diphtheria, and pertussis (Tdap), meningococcal, and human papillomavirus (HPV)), we examined cyclical patterns in vaccination. We analyzed HPV vaccine initiation only among female adolescents.

Results. Uptake of adolescent vaccines in the United States demonstrated cyclical patterns for each year and for each state (all P<0.001). Uptake was 5 times as frequent at the cycle’s peak as at its trough for Tdap booster, 10 times for meningococcal vaccine, and 5 times for HPV vaccine. Adolescent vaccination was highest in June, July, and August (three-month totals: Tdap booster, 40.2%; meningococcal vaccine, 41.1%; HPV vaccine, 38.7%). Nationally, concomitant vaccination (i.e., receipt of 2 or more vaccines on the same day) also demonstrated cyclical patterns each year (all P<0.001).

Conclusions. Adolescent vaccination had dramatically higher uptake during the summer months, particularly in August. Practitioners and researchers should anticipate summer peaks in adolescent vaccination when allocating resources, setting goals, and planning and evaluating efforts to increase uptake.