Epidemiological characteristics of measles in Beijing, 2011-2016

Abstract

Objective To analyze the epidemiological characteristics of measles in Beijing during the period of 2011-2016 and to explore the focal point of measles prevention and control. Methods A total of 5 715 measles cases reported by hospitals in Beijing from 2011 to 2016 were selected. Descriptive epidemiological analysis was conducted on measles incidence, regional distribution, time distribution and population characteristics. Chi-square test was used to analyze the difference between resident population and immigrant population. Results The average annual incidence was 4.50 /100 000 from 2011 to 2016 in Beijing, with the lowest incidence in 2012 (0.39/100 000, 80 cases) and the highest incidence in 2014 (11.08/100 000, 2 385 cases). The incidence peak was during March to May of a year, and the proportion was 66.02% (3 373/5 715). The incidence in the suburban area (0.52/100 000-12.61/100 000, 33-864 cases) were always the highest, except for 2012. The incidence of immigrant population (0.75/100 000-16.59/100 000, 76-1 332 cases) was higher than that of resident population (0.17/100 000-8.03/100 000, 22-1 053 cases), but incidence ratio decreased from 6.35 (1.08/0.17) in 2011 to 1.59 (7.60/4.78) in 2016. The measles cases were mainly children of <1 years old (14.28/100 000-297.02/100 000, 17-486 cases) and adults aged in 20-39 years old. The peak value were in 2011-2013 in age group of 20-29 years old (0.39/100 000-3.29/100 000, 20-175 cases) and in 2014-2016 in age group of 30-39 years old (8.14/100 000-15.95/100 000, 300-578 cases). The proportion without vaccination was 59.36% (501/844) of 8 months old to 6 years old and was 63.98% (318/497) in immigrant population which was higher than 52.74% (183/347) in resident population. The proportion of scattered children decreased from 5.71% (35/98) in 2011 to 9.93% (125/1 259) in 2016, and office workers increased from 5.10% (5/98) to 28.28% (356/1 259) as well as catering, commercial and housekeeping service personals increased from 26.53% (26/98) to 33.84% (426/1 259). 171 outbreaks were reported and the number ascended from 2 to 55. Conclusions The overall incidence of measles was rising in Beijing during the year of 2011-2016. So it is necessary to continue implementing the current measles elimination immunization strategy, to promote the vaccination timelines of 8 months children, and to encourage MCV vaccination of babysitter or family members and to expand measles vaccine coverage of workers. Key words: Measles; Incidence; Immunity; Vaccination