[Epidemiology of pertussis in adults and related factors in Tianjin, 2005-2014].

Abstract To understand the epidemiological characteristics of pertussis in adults and related factors in Tianjin. Descriptive epidemiological analysis was conducted by using the epidemiological data of pertussis in adults in Tianjin during 2005-2014. The transmission routes of family cluster cases were analyzed. ELISA was conducted to detect pertussis immunity levels in adults aged 18-83 years. The pertussis cases in adults accounted for 28.57%(252/882)of the total cases in Tianjin , the annual incidence of pertussis in adults was 0.16/100 000. The highest incidence was 0.46/100 000 in 2013. The age specific proportion of the cases was highest in age group 21-30 years(36.12%, 91/252). Three household transmission routes of pertussis were identified, the major one was adult-to-infant(77.78%,98/126). The parents were the infection sources of 81.64% of infant cases(80/98). Of the 904 study subjects, the average positive rate of antibody against pertussis was 55.20%(95%CI: 51.96%-58.44%). There were significant differences in antibody positive rate among different age groups(P= 0.015), and which had the linear correlation with the reported annual incidence(r=0.98, P=0.003)and showed upward trend(χ(2)=11.79, P=0.001). The study indicated that adults have become the population at high risk for pertussis and the major infection sources for infants in Tianjin. The positive rate of antibody against pertussis was low in adults. It is suggested to conduct pertussis vaccination in adults.