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

Abstract

Background Developing 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. Methods We 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. Results Out 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. Conclusion Several 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.

A data driven clinical algorithm for differential diagnosis of pertussis and other respiratory infections in infants

“…Current clinical case definitions for surveillance may miss cases early in the course of the disease and, as a matter of fact, a significant number of pertussis cases fulfilled the clinical case definition for surveillance only several days after the enrollment in this study. Specific algorithms, therefore, may help to improve early diagnosis even in low resource settings [25]. Moreover, the performance of case definitions is affected by the prevalence of the disease.…”

“…A possible change of pertussis case definition and duration of cough has long been debated [ 9 , 25 , 28 – 30 ]. To our knowledge, an algorithmic approach to refine pertussis case definitions and achieve a better performance has never been used, and deserves attention in perspective.…”

Diagnostic limitations of clinical case definitions of pertussis in infants and children with severe lower respiratory tract infection

“…Involving only suspected cases of pertussis to assess diagnostic accuracy of the same features on which the sample was selected has the potential of exaggerating the diagnostic accuracy of clinical criteria. [ 23 ]…”

Clinical and epidemiological features of pertussis in Salvador, Brazil, 2011–2016

“…Considering that non-specific symptoms of pertussis constitute a mandatory notification of a suspected case of pertussis, it is possible that this procedure could introduce bias into the classification of pertussis cases. Moreover, several studies have shown a higher frequency of pertussis in children aged one year or less, mainly those under six months, who present high numbers of hospitalizations and more frequent disease complications [ 1 , 13 , 24 – 27 ].…”

“…Fortunately, cure was the predominant outcome and no pertussis deaths were identified among the patients investigated during the study period. Indeed, the prognosis is generally good in most confirmed pertussis cases, with a typical mortality rate of around 2% [11,27,35].…”