Effect of Studying Abroad on Catch-Up Vaccination in Young Adults: A Study Using the Japan Pretravel Consultation Registry1.

Purpose: To investigate the effect of studying abroad on catch-up vaccination coverage for measles, rubella, mumps, varicella, and tetanus during the pretravel consultation among young adult travelers.

Methods: This retrospective cohort study analyzed data from the Japan Pretravel Consultation Registry (J-PRECOR) on individuals aged 18-21 years with childhood vaccination records. Propensity score weighting was used to estimate the average treatment effect on the proportion of participants receiving catch-up vaccination.

Results: Among 1,091 eligible participants, the catch-up vaccination need was highest for mumps (65.7%) and varicella (49.0%) and lowest for measles (9.9%) and rubella (14.0%). In the unadjusted analysis, the catch-up vaccination rate was 70.6% for tetanus, 50.9% for measles, 47.7% for rubella, 40.0% for mumps, and 23.9% for varicella. In the weighted analysis, the study-abroad group had significantly higher catch-up vaccination rates for measles (54.6% vs. 29.8%, P = 0.039), rubella (53.0% vs. 22.1%, P < 0.001), and varicella (26.8% vs. 10.9%, P = 0.002), whereas the non-study-abroad group had a higher catch-up vaccination rate for tetanus (62.4% vs. 78.4%, P = 0.024).

Conclusion: Compared with other travelers, the catch-up vaccination rate among travelers studying abroad was higher for measles, rubella, and varicella, but lower for tetanus. In clients planning to study abroad, vaccinations required for travel should be recommended in addition to those required by the host institution, and vaccination against highly infectious diseases with potential for complications, such as measles, rubella, mumps, and varicella, should be recommended to clients traveling for reasons other than studying abroad.