Social regulations predispose people to complete vaccination for vaccine-preventable diseases.

Japan experienced measles outbreaks in both 2006 and 2007 mainly among university students. Improvement of vaccine coverage against vaccine-preventable viral infections is the prime task for preventing outbreaks of viral infections. To elucidate the promoting factors for complete vaccination against measles, rubella, mumps, and varicella-zoster viruses, we conducted a case-control study among single university students in Japan. Information on vaccinations and clinico-demographical factors were collected using a self-administered questionnaire and a photocopy of the Maternal and Child Health Handbook. Logistic regression analysis was performed to estimate odds ratios (ORs) and their 95% confidence intervals (CIs) for two-time vaccination against measles and rubella viruses as mandatory vaccinations and at least one-time vaccination against mumps and varicella-zoster viruses as optional vaccinations. A total of 1,370 (744 medical, 508 paramedical, and 118 pharmaceutical) students were invited to participate, 960 (70.1%) of whom were enrolled in the study. Students aged < 20 years had a greater propensity for measles and rubella vaccinations (OR 7.8 [95% CI, 5.1-11.8] and OR 6.1 [95% CI, 3.7-10.0], respectively) compared with those aged ≥ 20 years. Students with a history of living over-seas for 1 month or longer were more likely to complete vaccination for measles (OR 4.4 [95% CI, 1.4-13.5] compared with those without such history. This significantly high vaccination coverage was attributed to the measles-rubella catch-up campaign by the Japanese government and the immunization regulations by foreign countries. These findings suggest that social regulations would predispose people to complete vaccination.