Epidemic of measles following the Nationwide Mass Immunization Campaign in City Y, China, 2010

Summary

Background: A prolonged measles epidemic occurred in City Y after a nationwide measles mass immunization campaign (MMIC) in 2010. We investigated this epidemic to know the cause of this epidemic and provide evidence-based recommendations for measles elimination strategies in China. Methods: Measles cases were diagnosed by national criteria. We collected the data on vaccination history for measles patients to estimate measles vaccine coverage of the population. A case-control study was conducted in Hospital Z among children <1 year old. Case-patients were measles outpatients treated at Hospital Z from November 1 to December 31. We randomly selected control-patients among all other outpatients. We reviewed medical records of case and control-patients to compare their exposure history at Hospital Z 7-21 days before illness onset. Results: Measles attack rate for all ages was 3.3/100,000 compared to 113/100,000 for children <1 year old. For children who were not age-eligible for the MMIC but later became age-elig