RESUMO
Objective@#To investigate the epidemiological characteristics of a pertussis outbreak in a primary school in Rizhao City, so as to provide reference for the prevention and control strategy of pertussis.@*Methods@#The method of field epidemiological investigation was used to determine case definition for case search and case investigation,and the characteristics of the outbreak were comprehensively analyzed through descriptive epidemiological method.@*Results@#The outbreak lasted for 29 days from April 19 to May 17, 2022, with a total of 14 cases detected. All the cases were students aged 6-7 years from Class 2, Grade 1 in this primary school,including 6 boys and 8 girls. The attack rates of boys and girls were 30.00% and 34.78%, respectively. The time interval from onset to diagnosis of 14 cases ranged from 2 to 22 days, with a median of 10 days. All of them had received 4 doses of Diphtheria and Tetanus and acellular Pertussis(DTaP) combined vaccine, and the interval between the last vaccination and the onset of disease was 5-6 years. After isolated treatment, all the 14 sick students recovered, without severe or death cases.@*Conclusion@#The outbreak of pertussis in a primary school may be related to the decline in the effectiveness of pertussis vaccine protection over time, the lax implementation of a school registration and reporting system for sick absenteeism, and the poor sensitivity of existing pertussis surveillance systems.