Epidemiological characteristics of pertussis from 1954 to 2017 in Taizhou, Zhejiang

Abstract

Objective To explore the epidemiological characteristics of pertussis from 1954 to 2017 in Taizhou prefecture of Zhejiang, so as to provide evidence for disease control and prevention. Methods Clinical data were collected from Historical Epidemic Surveillance Data Collection of Taizhou Prefecture and China Information System for Disease Control and Prevention, and immunization information was mainly collected from Taizhou Contagious Disease Control Records. The epidemiologic distribution and vaccine application of pertussis were analyzed by descriptive method. Results A total of 158 947 pertussis cases were reported from 1954 to 2017, with an average annual incidence of 53.66 per 100 000 population. A total of 298 cases died with the average annual mortality of 0.10 per 100 000 population and case fatality rate of 0.19%. The epidemic of pertussis in Taizhou experienced three phases in terms of periodic phase (from 1954 to 1989) , deperiodic phase (from 1990 to 1999) and periodic phase (from 2000 to 2017) again, and the epidemic period was 3-4 years. The pertussis incidence declined constantly after the application of diphtheria-tetanus-pertussis vaccine (DTP) . The incidence of pertussis decreased 92.41% after implementation of Expanded Program on Immunization. Since 2000, the periodicity had reappeared with incidence at low level, and most cases were under 1 year old with the proportion of 84.78% during 2011 to 2017. The incidence rate in 2017 (0.21 per 100 000 population) had reached the highest since 2000. Conclusions From 1954 to 2017, the prevalence of pertussis decreases gradually in Taizhou. The effect of Expanded Program on Immunization is obvious, but the epidemic changes over the last 10 years suggest that the reemergence of pertussis should be vigilant. Key words: Whooping cough; Epidemiologic characteristic; Program on immunization; Reemergence