The declining antibody level of measles virus in China population, 2009–2015

BACKGROUND: To eliminate measles, the coverage of more than 90% vaccine is required in China. Nonetheless, the measles incidence still reached to 3.88 per 100,000 in 2014, which is far more than the target of 1 per 1,000,000. Moreover, there is little national surveillance to measles antibody level indicating herd immunity status in China. METHODS: We detected the level of antibody to measles using commercially available indirect enzyme-linked immunosorbent IgG assays, and calculated the protection rate of population (PRP) to measles virus infection among health peoples in China. RESULTS: During the years 2009–2015, among the Chinese population aged 0–56, PRP was 94.7, 91.6, 91.6, 84.2, 82.1, 81.0, 75.4%, respectively. Among all age bands, the PRP is lowest among children less than 12-month-age, followed by people over 15 years old. CONCLUSION: Measles antibody level among healthy population has been declined since 2012, supplemented measles vaccination activity may be necessary to eliminate measles in China.