Analysis of pertussis surveillance 2017 to 2019 in Minhang District of Shanghai

Yan DU; Jia REN; Li-ping ZHANG; Xi WANG; Bao-fang JIN; Ye WANG; Ke-wen MEI; Xiu-hong TIAN

ABSTRACT

Objective:To analyze the source of infection， clinical symptoms and epidemiological characteristics of pertussis surveillance cases in Minhang District of Shanghai from 2017 to 2019，so as to provide the basis for pertussis surveillance and immunization strategy. Methods:Descriptive epidemiological method was used to analyze the pertussis surveillance cases. Results:A total of 334 cases were included in the pertussis active surveillance system， 237 cases were confirmed cases. There were 13 towns or streets in Minhang District， except for Pujin Street， all the other 12 towns or streets had cases. The high risk group （131/237， 55.27% of the cases） were the infants under five months old who did not reach the age of immunization or did not complete the basic immunization of diphtheria， tetanus， and acellular pertussis combined vaccine （DTaP）. The cases mainly occurred in March to July， accounting for 71.31% （169/237）. The highest culture-positive rate of Bordetella pertussis was in August （82.76%， 24/29）； the highest positive rate of polymerase chain reaction （PCR） detection was in March （58.82%， 20/34）. All the monitored cases had cough symptoms with an average cough days of 22.05±9.81 in confirmed cases. A total of 64 clustered outbreaks were detected， with an attack rate of 37.45% （94/251）. 32.91% （78/237） of the cases had contact history with coughing patients 21 days before the onset， and 94.87% （74/78） of them were family members. The aggregation of pertussis was mainly transmitted from adults to infants and infants to adults. Conclusion:Children under five months old are the high incidence population of pertussis， and family members are the main source of infection. It is suggested that pertussis monitoring and prevention should be carried out in adolescents and adults.