Pertussis clinical case definition: Time for change in developing countries?

Sheila Gopal Krishnan,Malini Devi Ramadras,Rahmah Yunus,Weng Hong Fun,Sondi Sararaks,Yik Fan Lye,Monica Cartelle Gestal

doi:10.1371/journal.pone.0219534

Abstract

BackgroundDeveloping countries still struggle with late detection and mortality from pertussis. A review of clinical case definitions is necessary for early disease detection. This paper aimed to study possible clinical characteristics for earlier pertussis detection in a sporadic setting.MethodsWe conducted a retrospective review of medical and laboratory records in a general paediatric ward of a district hospital in a developing country. Inclusion criteria were all children hospitalised with nasopharyngeal swab taken for Bordetella pertussis. We compared sensitivity and specificity of World Health Organization diagnostic criteria with other clinical characteristics. Polymerase chain reaction Bordetella pertussis was the gold standard used.ResultsOut of 207 eligible admissions, the study retrieved 128 complete records. Approximately half of the children were less than 3 months old. The World Health Organization diagnostic criteria had a low sensitivity (15%), but high specificity (92%). In comparison, combinations that included paroxysmal cough, ill contact and facial congestion had higher sensitivity. Increasing cough duration improved specificity while compromising sensitivity.ConclusionSeveral clinical characteristics such as paroxysmal cough, facial congestion and a history of ill contact have potential for early clinical detection. Conventional emphasis on cough duration may hamper early detection.

Highlights

Pertussis remains a major cause of childhood illness with estimated case fatality rates of 4% in developing countries [1]
A resurgence in the incidence of pertussis has been observed in the recent years globally [3], and implicated were acellular vaccine effectiveness, asymptomatic transmission from individuals vaccinated with acellular vaccines [4], genetic adaptation of Bordetella pertussis [5], vaccination delay or refusal [6], improved surveillance and laboratory capabilities [7] as well as overall increased awareness of the disease [2]
At the ground level, diagnosing pertussis remains a major challenge for clinicians

Summary

Introduction

Pertussis remains a major cause of childhood illness with estimated case fatality rates of 4% in developing countries [1]. This disease spares no age group, though infants have the highest casualties [2]. Most clinical case definitions require a two-week cough with at least one additional symptom of paroxysmal cough, inspiratory whoop, posttussive vomiting or apnoea [9]. France requires cough of more than 7 days with at least one symptom of paroxysmal cough, whooping, or vomiting, and a high index of suspicion if clinical presentation is at early infancy [9]. A review of clinical case definitions is necessary for early disease detection. This paper aimed to study possible clinical characteristics for earlier pertussis detection in a sporadic setting

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