Pertussis outbreak in southern Ethiopia: challenges of detection, management, and response

Abstract

Background: Despite the availability of effective vaccines, pertussis remains endemic with high fatality rates in low and middle-income countries (LMIC). This study aims to describe an outbreak of pertussis in a health district of Ethiopia. The study highlights the challenges faced by the health system in identifying pertussis cases and appropriately responding to the outbreak at the district level. Methods: A descriptive cross-sectional study was conducted using data sourced from the District Public Health Emergency and Management (PHEM) surveillance service and outbreak management field reports. Stratified attack rates and fatality rates for pertussis are described. Systemic problems leading to the outbreak are explored and narrated. A modified CDC pertussis case definition was employed with a polymerase chain reaction used to confirm cases. Results: From September 2018 to January 2019, 1840 suspected, probable, and confirmed pertussis cases and six deaths were identified. Pertussis cases ranged from 1 month to 51 years in age. An outbreak occurred in 14 out of the 24 villages of Dara Malo district. The overall attack rate was 1708 per 100,000 population with a fatality rate of 3.3 per 1000 pertussis cases. The highest attack rate of 12,689/100,000 was seen in infants. Among confirmed, probable and suspected pertussis cases, only 41.1% had completed the three-dose pertussis vaccine's primary schedule. The household survey revealed a population coverage of 73.4 and 40.8% for Pentavalent vaccine dose one and three respectively. Investigations suggested the existence of a poor cold chain management system in the study area. Conclusions: There is an urgent need to build capacity to strengthen routine vaccination services and improve the maintenance of the vaccine cold chain. Other LMICs are urged to take lessons learned from this outbreak to strengthen their own vaccination programs and capacitate health workers to manage local outbreaks.

Pertussis outbreak investigation in Likimsa-Bokore kebele, Meda Walebu district, Bale zone, Oromia region, Ethiopia, 2019

“…Out of three deaths reported from pertussis outbreak, two have occurred among females with a case fatality rate of 0.91%. This result is in line with the report of a pertussis outbreak investigation in Mekdela district, Northwest Ethiopia [9], the Dara Malo district, Southern Ethiopia in 2018 [17], and the Janamora district, Amhara Regional State, Ethiopia in 2017 [18]. This nding indicates females are more affected than males which could be explained as females spend more time working at home and caring for children or adults, which puts them at higher risk of contracting the disease.…”

“…Children aged below ve years are the most affected age group with an attack rate of 198/1000, which is in line with the ndings of a pertussis outbreak investigation in Mekdela district, Northwest Ethiopia [9], the Dara Malo district, Southern Ethiopia in 2018 [17], and with the study conducted in Aleppo [20]. The sex-speci c attack rate in this study indicates a high attack rate among females (57/1000) than males (54/1000).…”

“…However, more than half cases 256 (58.3%) have occurred in under ve years children and almost one-third of cases 80 (31.6%) in under-ve years children were reported among infants below one year. The overall attack rate of 55/1000 residents of Likimsa-Bokore village was much higher than the previously documented pertussis attack rate of 130 per 100,000 population reported in Mekdela district, Northwest Ethiopia in 2017 [9], and 1708 per 100,000 inhabitants of Dara Malo district, Southern Ethiopia in 2018 [17]. Similarly, the attack rate reported in this study is higher than the attack rate of 130 per 100,000 population reported in pertussis outbreak in Janamora district, Amhara Regional State, Ethiopia in 2017 [18], and the 14 per 1000 population of Goilala district, Central Province in Papua New Guinea in 2011 [19].…”

Pertussis outbreak investigation in Northwest Ethiopia: A community based study

“…The southern part of our country indicated that the overall attack rate was 1708 per100,000 population, and the fatality rate 3.3 per 1000 cases. This attack rate was very high in infant age groups and only 41% had completed the three-dose pertussis vaccine primary schedule, whereas the household survey resulted in 73% pentavalent vaccine coverage [ 18 ].…”

Spatiotemporal analysis of pertussis in Hunan Province, China, 2009–2019

“…With the widespread implementation of pertussis vaccine immunisation, the incidence of this disease has decreased significantly 4 5. However, in the past two decades, outbreaks of pertussis have been reported in many areas worldwide,6–9 and large-scale outbreaks of pertussis (termed as ‘pertussis recurrence’) have also been reported in Shandong, Taiwan, and other regions in China 10 11…”