Efficacy of measles and rubella vaccination one year after the nationwide campaign in Shiraz, Iran.

BACKGROUND: The World Health Organization target for measles elimination in the Eastern Mediterranean Region was established in 2010. In Iran, the national measles-rubella campaign, targeting individuals aged 5-25 years, was initiated in December 2003.

METHODS: To evaluate the impact of the campaign after one year, 909 serum samples were collected in Shiraz, southern Iran, from a population aged 6-26 years, divided into five groups according to age. IgG antibodies were tested using ELISA for the measles and rubella antibodies, and the plaque reduction neutralization test (PRNT; measles) was used for samples with equivocal results.

RESULTS: Measles protective immunity reached 80.6%, 72.7%, 84.9%, and 87.5% and rubella immunity reached 91.0%, 99.6%, 99.6%, and 97.0% for the age groups 6-10, 11-15, 16-20, and 20-26 years, respectively. Seropositivity to the rubella virus in this population was high, especially in women of childbearing age (98.9%), thereby preventing congenital rubella infections. However for measles, it was significantly lower than the rate required to achieve >or=95% coverage for elimination.

CONCLUSIONS: These data indicate that an increase in immunization coverage by supplementary administration of a second dose of measles vaccine is needed to interrupt the endemic transmission of the measles virus.