Assessing the spatial and temporal analysis of pertussis transmission among Hanoi, Vietnam population in the period of 2015 to 2019

Abstract

Despite the vaccination program’s great effectiveness, pertussis outbreaks are still reported with substantial spatial heterogeneity. Thus, this study aimed to investigate the spatio-temporal patterns of pertussis to determine the hot spots with the high-risk transmission in Vietnam from 2015 to 2019. This study was designed as a cluster case study from December 2019 to October 2020 in Hanoi, Vietnam. Data on 564 pertussis cases were collected via the pertussis case report form of the national immunization program and disease surveillance system of the Hanoi Centers for Disease Control and Prevention (CDC) from 2015 to 2019. Knox Test was applied to assess the risk of spreading epidemics by space and time via a program running on R software. The pertussis incidence per 100 000 population was the highest in the inner city, with an average of 2.96/100000 in 2015. An area with an extremely high risk of infection was located within 200 meters away from the pertussis case and within 40 days, apart from the detecting time (Relative risk (RR) = 3 to 222). Sixty-two hot spot clusters were defined, mainly distributed in the inner city areas, while only a few risk clusters belonged to suburban districts. By using well-defined spatio-temporal distributions, a geographical area of high pertussis transmission risk was identified. Our findings play a fundamental part in developing the ongoing and comprehensive database to complete the disease surveillance system and design effective intervention measures.