Pertussis: a cluster of linked cases in the United Kingdom, 2006.

Pertussis is a vaccine-preventable disease with a high rate of complications, especially in young children. It often presents in an atypical fashion in adults and adolescents, making diagnosis difficult. This report describes a cluster of linked cases of three adults and one infant in a family, spread across the United Kingdom (UK). The initial follow-up was of a 20-year-old student with clinical symptoms of pertussis. This diagnosis led to the discovery of two other unvaccinated adult family members with symptoms that fit the case definition for pertussis and a laboratory-confirmed tertiary case in an unvaccinated infant who had to be hospitalised. This report aims to act as a reminder for including pertussis as a differential diagnosis in patients with a long duration of respiratory symptoms and highlights the importance of rapidly identifying and managing close contacts of cases. This is key in protecting the most vulnerable - namely, infants - from infection.