Epidemiological characteristics of measles before and after aarge scale supplementary immunization activities in Minhang District of Shanghai / 公共卫生与预防医学

ABSTRACT

Objectives Comparative analysis on epidemiological characteristics of measles in Minhang District before and after Large scale supplementary immunization activities of measles containing vaccine(MCV) in 2010. Methods Measles incidence data of MCV-SIA in 2010 and the first five years before 2010 (from January 1, 2005 to December 31, 2009), the next five years (from January 1, 2011 to December 31, 2015) and the second five years (from January 1, 2016 to December 31, 2020) after were collected. Descriptive epidemiological method was used for comparative analysis. Results The incidence rate of measles in Minhang District, Shanghai after MCV-SIA in 2010 showed a significant downward trend, The average annual incidence (per 100 0000) in the first 5 years before 2010 was 155.96, SIA was 30.08,The next five years was 29.52, The second five years was 2.84,There was statistical difference in the annual incidence rate between the four groups.（χ2=3165.821，P2=1.646，P=0.223）The proportion of 8-month-old children under the age of MCV decreased from 15.46% in the first five years of MCV-sia to 5.88%,In the second five years after MCV-sia, the proportion of 10-14 age group increased from 7.81% to 13.83%, The susceptible population of measles before MCV-SIA was less than 8 month old and under the age of MCV initial immunization, no migrant workers with no history of immunization and adults with registered residence. Once there is a source of infection, it is easy to cause the spread of the epidemic. After MCV-SIA, foreign students in international schools and nonworking population became the focus of measles. Of the 95 cases in which measles virus genotypes were available in the next five years, 2 (2.11%) were A genotype, and 93 (97.89%)were the indigenous H1 genotype ; Of the 7 cases in which measles virus genotypes were available in the second five years,7 (100%)were the indigenous H1 genotype . Conclusions After MCV-SIA, the comprehensive measles prevention and control measures can effectively control the incidence and prevalence of measles in Minhang District. But circulation of the indigenous H1 genotype was not interrupted, the work of normalization measures to eliminate measles also needs to cooperate with many departments to strengthen the prevention and control measures of measles in foreign schools and the nonworking population.