The mumps surveillance data from 2004 to 2011 showed that the incidence of mumps remained high after the one-dose measles-mumps-rubella (MMR) vaccine was introduced in China in 2008. A cross-sectional survey of mumps IgG in the general population of Jiangsu province was conducted in 2012 to gain comprehensive information on the immunity profile of the general population. The mean incidence was 15.2 per 100 000 individuals in Jiangsu province from 2004–2013. Two mumps incidence peaks were observed each year after introduction of the one-dose MMR vaccine. The seroprevalence did not significantly differ by region or sex, while the GMC significantly differed by region and sex. The overall GMC in Jiangsu province was 99.1 IU/ml (95% CI: 90.1–108.2), while the seroprevalence was only 59.1% (95% CI: 56.5–61.6). The seroprevalences for the 2 age groups that received the one-dose MMR vaccine, with reported coverage exceeding 95%, were 42.6% and 70.0%, respectively. The data on the incidence, MMR coverage, and seroprevalence in children younger than 6 years of age indicate that a two-dose MMR strategy should be considered. Mumps surveillance should be strengthened in children aged 6–11 and in those aged 12–17 because of their high contact rates and relatively low seroprevalences.

BackgroundChanges in the epidemiological characteristics of measles since 2007 appeared in the Jiangsu province. Although the reported coverage with two doses of measles vaccine was greater than 95% in most regions of the province, measles incidence remained high across the whole province. Cross-sectional serological surveys of measles antibodies in the Jiangsu province of China were conducted from 2008 to 2010 to assess and track population immunity.MethodsMeasles-specific IgG levels were measured in serum samples using ELISA. GMTs and seroprevalence with 95% CIs were calculated by region, gender, and age. ANOVA and χ2 tests were used to test for statistically significant differences between groups for GMT levels and seroprevalence, respectively.ResultsSeroprevalence showed a significantly increasing trend annually (CMH χ2 = 40.32, p<0.0001). Although the seroprevalence among children aged 2–15 years was consistently over 95%, vaccine-induced measles antibodies may wane over time. Measles seropositivity in the Jiangsu province was 91.7% (95% CI: 90.1–93.2%) in 2010. Among adults aged 15 to 29-year-olds, the seropositivity rate was 88.4% (95% CI: 82.7–92.8%).ConclusionsVaccination strategies may need to be adjusted depending on the individual age and regions, particularly individuals between the ages of 8 months-14 years old and 20–29 years old. Additional SIAs are likely required to eliminate measles in China.

Introduction:Endemic measles persists in China, despite >95% reported coverage of two measles-containing vaccine doses and nationwide campaign that vaccinated more than 100 million children in 2010. In 2011, almost half of the 9943 measles cases in China occurred in children eligible for measles vaccination. We conducted a case-control study during 2012–2013 to identify risk factors for measles infection in children aged 8 months–14 years.Methods:Children with laboratory-confirmed measles were age- and neighborhood-matched with three controls. We interviewed parents of case and control infants on potential risk factors for measles. We calculated adjusted matched odds ratios and 95% confidence intervals of risk factors. We calculated attributable fractions for risk factors that could be interpreted as causal and vaccine efficacy (VE) for the measles containing vaccine (MCV) used in the Chinese immunization program.Results:In all, 969 case-patients and 2845 controls were enrolled. In multivariable analysis, lack of measles vaccination both overall (mOR 22.7 [16.6, 31.1] and when stratified by region (east region, mOR 74.2 [27.3, 202]; central/western regions mOR 17.4 [12.5, 24.3]), hospital exposure (mOR 63.0, 95% CI [32.8, 121]), and migration among counties (overall mOR 3.0 [2.3, 3.9]) were significant risk factors. The calculated VE was 91.9–96.1% for a single dose of MCV and 96.6–99.5% for 2 doses.Conclusions:Lack of vaccination was the leading risk factor for measles infection, especially in children born since the 2010 supplementary immunization activity. Reducing missed vaccination opportunities, improving immunization access for migrant children, and strengthening school/kindergarten vaccine checks are needed to strengthen the routine immunization program and maintain progress toward measles elimination in China.

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Children who received one-dose MMR in kindergarten and primary school were at high risk of mumps infection, and waning immunity occurred with time. Determining the optimal age for the second dose of MMR in children should be prioritized to prevent mumps epidemics.