Measles elimination: A mass immunization campaign in Romania

Despite high single-dose measles immunization. coverage since the 1980s and high 2-dose coverage since 1995, Romania experienced a measles epidemic be tween November 1996 and June 1998. Apart from unvaccinated children younger than 2 years, the largest numbers of cases occurred among persons aged 8 t hrough 18 years, 73% of whom had previously been vaccinated.(1) Vaccine eff ectiveness studies conducted during the epidemic found the measles vaccine to be highly effective, indicating that measles among vaccinated school-age d children was primarily due to failure to respond to a single dose of meas les vaccine.(2) A nationwide campaign was conducted to immunize school-aged children, most of whom were not immunized under the second-dose policy established in 1994 (persons aged 1018 years). This campaign appears to have reduced susceptib ility to levels required to prevent further measles outbreaks and interrupt the transmission of indigenous measles. Preschool-aged children were not i ncluded, because the campaign should decrease measles transmission and redu ce the risk of exposure among preschool-aged children, who are now covered by the routine 2-dose schedule. Because of the size of the campaign and the goal of the World Health Organi zation's (WHO's) European region to eliminate measles by 2007, special effo rts were made to monitor Romania's experience.(3)