Analysis of the Auckland 2014 measles outbreak indicates that adolescents and young adults could benefit from catch-up vaccination.

AIM: To analyse the epidemiology, serology and vaccine effectiveness in a recent New Zealand measles outbreak that started in Auckland, from December, 2013 to June, 2014, to guide further preventive measures.

METHOD: Cases had a clinically compatible illness, which was either confirmed by PCR or serology, or were linked to a laboratory confirmed case.

RESULTS

A total of 113 cases with 3,113 contacts were traced and managed in the Auckland region. Thirteen overseas acquired cases, produced a total of 98 locally acquired secondary cases, (plus two cases with unknown travel history). The majority of cases occurred in adolescents and young adults; 68/113 cases (60.1%) were aged 10 to 19 years. Among cases, 38.9% (44/113) were unimmunised, and 31.8% (36/113) had unknown immunisation status. A further 15.0% (17/113) of cases had received one or two doses of measles, mumps, rubella (MMR) vaccine. Of the contacts who underwent serological testing for immunity (n=735), the lowest levels of serological immunity were observed in people aged 10 to 24 years. Vaccine effectiveness was calculated for the 15-24 year age cohort at 92% (95%CI; 82-97).

CONCLUSION

Results suggest that an adolescent catch-up immunisation programme would prevent further outbreaks of imported measles.