Epidemiology of measles in infants aged8 months and related risk factors in Wenzhou, Zhejiang

Objective To understand the reason for the high incidence of measles in infants aged8 months in Wenzhou, Zhejiang province, and provide evidence for the development of measles immunization strategy to reduce the incidence of measles in young infants. Methods Descriptive epidemiological analysis was conducted on the 350 measles cases in infants aged8 months in Wenzhou reported to national measles surveillance information management system during 2009-2013. Frequency matching case control study was conducted (case group: measles cases reported through surveillance system,control group: non measles cases). Logistic regression analysis was done to identify risk factors, and the serum antibody level to measles virus was detected. Results The average annual incidence rate of measles was 83.05/lakh during 2009-2013 in Wenzhou, the cases in infants aged8 months accounted for 35.79% of the total and were mainly distributed in age group 6-8 months. The OR for infants receiving no medical care 7 days before the onset was 0.68 (95% CI: 0.49-0.94). Compared with the infants in floating population,the OR was 0.53 (95% CI: 0.39-0.72) for local infants aged8 months and 1.53 (95% CI: 1.07-2.18) for local infants aged3 months.The detection of serum measles antibody level in healthy infants indicated that the mean antibody level was 214.94 IU/L for the newborns and 86.38 IU/L for infants aged 6 months, and over 80% of infants in Wenzhou might be susceptible to measles at the age of 6 months,. Conclusion Infants aged8 months are at risk to be affected by measles due to low antibody level among them and other risky factors, such as nosocominal infection and being floating population. The reproductive women are recommended to receive MCV vaccination before marriage to increase maternal measles antibody level. It is necessary to strength the management of floating population and control of nosocominal infection.