Diagnostic study of pertussis using PCR in primary care clinics

Pertussis is a respiratory infection caused by bacteria of the genus Bordetella, mainly pertussis and parapertussis species. Despite the high vaccination coverage in developed countries, it is considered a re-emerging disease that is also underreported and underdiagnosed, especially in patients who do not require hospital referral.

Descriptive, prospective and multicentre study of pertussis diagnosis and contact investigation in 17 primary care paediatric clinics through collection of samples for polymerase chain reaction (PCR) testing over a period of 4 years and after the implementation of routine vaccination against pertussis during pregnancy.

Pertussis was diagnosed in a total of 50 patients; the estimated incidence in these years was higher compared to previous rates in the paediatric age group. Fourteen percent of the cases occurred in children aged less than 1 year. The mean age was 6.7 years. Cough was present in 100% of cases, followed in frequency by vomiting and rhinorrhoea. Only 1 patient required hospital admission, and none died or developed complications. B. pertussis was the predominant causative agent. Only 40% knew the source of infection. In 26% of the cases, pertussis was confirmed in contacts of the patient by PCR, and in 46% it was suspected based on the clinical presentation but without microbiological confirmation.

Access to diagnostic tests (PCR) for pertussis in primary care allows us to optimise its diagnosis and treatment, to break the chain of transmission, to know the real incidence rates and to assess the impact of routine vaccination of pregnant women on this disease.