A cross sectional survey measuring sero-incidence of pertussis infection among Japanese junior and senior high school students in 2013 and 2014

Abstract Pertussis in adolescents has been increasingly documented in recent years, but diagnosis from the clinical symptoms is difficult. Serological diagnosis with IgG antibody to pertussis toxin (IgG PT) is useful for detecting pertussis cases in this population. However, no serological criterion for recent infection has been fully validated and large-scale, longitudinal serological data among Japanese junior and senior high school students are lacking. Paired serum samples of 3243 junior and senior high school students, collected in 2013 and 2014, were analyzed for IgG PT and its relationship to possible risk factors. Regression analysis showed an average decrease of 35% in IgG PT between 2013 and 2014. In 2013, 4.4% of the students showed IgG PT levels ≥100 EU/mL, as did 3.7% in 2014. The seroincidence, defined as [IgG PT] change from B. pertussis in Japanese adolescents. The results also support a “≥4-fold rise in IgG PT” as a useful component of the sero-epidemiological surveillance for pertussis.