A Measles Outbreak among Unvaccinated Children of Migrant Workers: Zhejiang Province, June to August, 2010

Background: Improving vaccination coverage among children of migrant workers (MW) is an important part of Chinese goal of measles elimination by 2012. On July 6, 2010, the parents of a confirmed measles patient reported several similar patients in their village. An investigation was conducted to verify and understand the cause of the outbreak.

Methods: A suspected case was onset of fever and rash among a resident of this village and other neighboring villages during June 1 to August 3, 2010. A confirmed case was a suspected case with measles-specific IgM identified in the serum. We conducted door-to-door visits and searched measles surveillance records to find cases. A retrospective cohort study among children of MW children aged 8 months-14 years was conducted to identify risk factors for measles infection.

Results: We identified 19 measles cases (2 were previously reported) in the village, all among children of MW. Children aged 1-2 years had the highest attack rate (13%). The primary case-patient had onset on June 4 when she arrived from another province. All cases had been treated at 3 unlicensed private clinics that had not reported cases. From a sample, measles vaccine coverage was 81% among 315 children of MW and 100% among 23 resident children (p <0.02). Among 61 unvaccinated children, the 16 who had close contact with measles patients had an 88% (14/16) attack rate compared to 4.4% (2/45) of those who did not (relative risk=20, 95% confidence interval: 5.7-94).

Conclusions: The lower measles vaccine coverage among children of MW and delayed reporting contributed to this outbreak. We recommend improved immunization services for children of MW and better targeting of surveillance in this group. 

Year: 
2009
Author (s): 

Jie Gao, H.Q. He, J.C. Shen, Z.Y. Huang, H.L. Ma, S.Y. Luo, E.F. Chen

Presenter (s): 
Gao
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