Review on pertussis case definitions: a need for reliable disease surveillance

Existing clinical case definitions of pertussis are decades old and mainly rely on clinical signs and symptoms in infants and children. In the recent past, an age shift of pertussis towards adolescents and adults has been noted and disease presentation often is different from that in children. Therefore, in 2011 the Global Pertussis Initiative (GPI) proposed an age-stratified case definition, but its uptake has been slow. This prompted members of the GPI steering committee to critically review the case definition. In preparation for this, we performed a review to learn which case definitions have been used worldwide.

We performed a narrative literature review to collect publications from January 1, 1975, to September 1, 2025, which include pertussis case definitions. This was complimented by a survey amongst GPI members to gather case definitions currently in use for pertussis surveillance in their countries.

The literature review identified 117 relevant publications. The two most often used case definitions were those proposed by CDC and WHO, followed by individual case definitions developed by the respective investigators for the purpose of their studies. Additionally, GPI members provided 16 country-specific surveillance case definitions. Cough and typical pertussis signs paroxysms, whooping and post-tussive vomiting are most commonly used clinical criteria. With regards to laboratory confirmation of B. pertussis infection, all case definitions require at least one criterion, most often a positive culture and/or PCR, followed by specific serology. Most case definitions do not use age-specific criteria.

Many different case definitions are in use all over the world. Most of them are focusing on the typical presentation of pertussis, i.e. disregarding less typical disease presentations and do not use age-specific criteria. This hampers a reliable and comparable disease surveillance. Therefore, a harmonized case definition that could be used globally would be highly welcome.

Not applicable.