The performance of respiratory illness surveillance case definitions to detect Bordetella pertussis in children aged < 5 years seeking healthcare for respiratory illness in South Africa, 2017-2023

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dc.contributor.advisorDe Voux, Alex
dc.contributor.advisorWalaza, Sibongile
dc.contributor.authorJensen, Katherine
dc.date.accessioned2025-12-01T09:43:31Z
dc.date.available2025-12-01T09:43:31Z
dc.date.issued2025
dc.date.updated2025-12-01T06:44:02Z
dc.description.abstractBackground: Pertussis is vaccine‐preventable and requires surveillance to guide interventions. Assessing the performance of syndromic surveillance and the World Health Organization (WHO) pertussis case definitions can improve sensitivity and accuracy in detecting laboratory‐confirmed Bordetella pertussis, ensuring effective monitoring in South Africa. Methods: We conducted a secondary analysis of respiratory illness surveillance data among children aged <5 years across sentinel sites from January 2017 through December 2023. Participants were enrolled as either outpatients eligible for influenza‐like illness (ILI), or hospitalised patients eligible for severe respiratory infection (SRI) surveillance. Nasopharyngeal swabs were tested for B. pertussis using polymerase chain reaction (PCR). Sensitivity, specificity, and other performance indicators of case definitions were evaluated against PCR results. Results: Of 23,887 participants, 23,640 (99.0%) had PCR results. B. pertussis was detected in 0.7% (30/4,125) from ILI and 1.6% (314/19,517) from SRI surveillance. Compared to the WHO pertussis case definition, a modified WHO pertussis case definition which includes apnoea and omits cough duration, improved sensitivity (ILI: 30.0% vs. 43.3%; SRI: 55.7% vs. 60.2%), but reduced specificity (ILI: 90.5% vs. 75.8%; SRI: 88.3% vs. 80.9% %). Negative predictive values were high for both definitions (ILI: 99.5% vs. 99.4%; SRI: 99.2% vs. 99.2%). The WHO pertussis case definition missed 44.3% of hospital laboratory‐confirmed cases, while the modified case definition missed 39.8%. Conclusion: Both WHO and modified pertussis case definitions missed many laboratory‐confirmed pertussis cases, likely underestimating disease burden. Revising the WHO pertussis case definition and integrating pertussis into syndromic surveillance is recommended to improve detection while optimising resources.
dc.identifier.apacitationJensen, K. (2025). <i>The performance of respiratory illness surveillance case definitions to detect Bordetella pertussis in children aged < 5 years seeking healthcare for respiratory illness in South Africa, 2017-2023</i>. (). University of Cape Town ,Faculty of Health Sciences ,Department of Public Health and Family Medicine. Retrieved from http://hdl.handle.net/11427/42371en_ZA
dc.identifier.chicagocitationJensen, Katherine. <i>"The performance of respiratory illness surveillance case definitions to detect Bordetella pertussis in children aged < 5 years seeking healthcare for respiratory illness in South Africa, 2017-2023."</i> ., University of Cape Town ,Faculty of Health Sciences ,Department of Public Health and Family Medicine, 2025. http://hdl.handle.net/11427/42371en_ZA
dc.identifier.citationJensen, K. 2025. The performance of respiratory illness surveillance case definitions to detect Bordetella pertussis in children aged < 5 years seeking healthcare for respiratory illness in South Africa, 2017-2023. . University of Cape Town ,Faculty of Health Sciences ,Department of Public Health and Family Medicine. http://hdl.handle.net/11427/42371en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Jensen, Katherine AB - Background: Pertussis is vaccine‐preventable and requires surveillance to guide interventions. Assessing the performance of syndromic surveillance and the World Health Organization (WHO) pertussis case definitions can improve sensitivity and accuracy in detecting laboratory‐confirmed Bordetella pertussis, ensuring effective monitoring in South Africa. Methods: We conducted a secondary analysis of respiratory illness surveillance data among children aged <5 years across sentinel sites from January 2017 through December 2023. Participants were enrolled as either outpatients eligible for influenza‐like illness (ILI), or hospitalised patients eligible for severe respiratory infection (SRI) surveillance. Nasopharyngeal swabs were tested for B. pertussis using polymerase chain reaction (PCR). Sensitivity, specificity, and other performance indicators of case definitions were evaluated against PCR results. Results: Of 23,887 participants, 23,640 (99.0%) had PCR results. B. pertussis was detected in 0.7% (30/4,125) from ILI and 1.6% (314/19,517) from SRI surveillance. Compared to the WHO pertussis case definition, a modified WHO pertussis case definition which includes apnoea and omits cough duration, improved sensitivity (ILI: 30.0% vs. 43.3%; SRI: 55.7% vs. 60.2%), but reduced specificity (ILI: 90.5% vs. 75.8%; SRI: 88.3% vs. 80.9% %). Negative predictive values were high for both definitions (ILI: 99.5% vs. 99.4%; SRI: 99.2% vs. 99.2%). The WHO pertussis case definition missed 44.3% of hospital laboratory‐confirmed cases, while the modified case definition missed 39.8%. Conclusion: Both WHO and modified pertussis case definitions missed many laboratory‐confirmed pertussis cases, likely underestimating disease burden. Revising the WHO pertussis case definition and integrating pertussis into syndromic surveillance is recommended to improve detection while optimising resources. DA - 2025 DB - OpenUCT DP - University of Cape Town KW - surveillance KW - whooping cough KW - pertussis KW - case definition KW - sensitivity KW - specificity KW - predictive value KW - children KW - southern Africa LK - https://open.uct.ac.za PB - University of Cape Town PY - 2025 T1 - The performance of respiratory illness surveillance case definitions to detect Bordetella pertussis in children aged < 5 years seeking healthcare for respiratory illness in South Africa, 2017-2023 TI - The performance of respiratory illness surveillance case definitions to detect Bordetella pertussis in children aged < 5 years seeking healthcare for respiratory illness in South Africa, 2017-2023 UR - http://hdl.handle.net/11427/42371 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/42371
dc.identifier.vancouvercitationJensen K. The performance of respiratory illness surveillance case definitions to detect Bordetella pertussis in children aged < 5 years seeking healthcare for respiratory illness in South Africa, 2017-2023. []. University of Cape Town ,Faculty of Health Sciences ,Department of Public Health and Family Medicine, 2025 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/42371en_ZA
dc.language.isoen
dc.language.rfc3066eng
dc.publisher.departmentDepartment of Public Health and Family Medicine
dc.publisher.facultyFaculty of Health Sciences
dc.publisher.institutionUniversity of Cape Town
dc.subjectsurveillance
dc.subjectwhooping cough
dc.subjectpertussis
dc.subjectcase definition
dc.subjectsensitivity
dc.subjectspecificity
dc.subjectpredictive value
dc.subjectchildren
dc.subjectsouthern Africa
dc.titleThe performance of respiratory illness surveillance case definitions to detect Bordetella pertussis in children aged < 5 years seeking healthcare for respiratory illness in South Africa, 2017-2023
dc.typeThesis / Dissertation
dc.type.qualificationlevelMasters
dc.type.qualificationlevelMPH
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