Hepatitis A serostatus and vaccination outcomes after on-campus education and point-of-care antibody testing

Susceptibility to hepatitis A virus (HAV) remains high among young adults in Korea, reflecting birth-cohort effects and vaccination history. Because foodborne transmission has contributed to outbreaks, students in food and nutrition or culinary arts represent a relevant target group as future food handlers. We aimed to estimate anti-HAV immunoglobulin G (IgG) seroprevalence, describe pre- to post-intervention changes in knowledge, perceptions and vaccination intention and report two-dose vaccination completion and its correlates.

From April 2023 to December 2024, we conducted a campus-based hepatitis A prevention program at four universities. Students completed a baseline questionnaire before the session and a post-intervention questionnaire immediately after the education session and same-visit POCT result feedback. Students who were IgG-negative and had no verified prior two-dose vaccination in the national Immunization Registry Information System (IRIS) were referred to public health centers for no-cost vaccination. Two-dose completion was defined as IRIS documentation of a second HAV vaccine dose by the study end date. We modeled anti-HAV IgG positivity using mixed-effects logistic regression with an institution-level random intercept, and series completion (and correlates) using modified Poisson regression with institution-clustered robust standard errors.

Of 692 participants who underwent anti-HAV IgG POCT, 188 (27.2%) were IgG-positive and 504 (72.8%) IgG-negative. Among IgG-negative participants, 37 had documented prior two-dose vaccination and were not vaccine-eligible. The remaining 467 were vaccine-eligible (0 dose n = 435, 1 dose n = 32). Overall, 354/467 (75.8%) completed the two-dose series. Baseline intention was strongly associated with series completion (aRR 1.55; 95% CI, 1.39-1.72). Among those initially no/undecided (n = 114), endorsing vaccine distrust was associated with higher completion (aRR 1.46; 95% CI, 1.09-1.98).

In a cohort of future food handlers with a susceptibility gap, a campus-based program integrating standardized education with same-visit anti-HAV IgG testing and vaccination record verification achieved high two-dose completion among those without evidence of protection. These findings inform targeted young-adult hepatitis A prevention strategies by using on-site triage to focus counseling and referral on susceptible individuals and reduce reliance on off-site testing and return visits. Comparative studies are needed to assess the incremental value and cost-effectiveness of on-site testing and serostatus feedback.