New influenza A (H1N1) 2009 in Primary Care: what have we found?

Objective: to describe the clinical features of pandemic influenza cases diagnosed in primary health care by sentinel pediatricians who participate in the PIDIRAC surveillance scheme (Programa de información diaria de las infecciones respiratorias agudas de Catalunya).

Methods: study sample included the cases of confirmed influenza A (H1N1) 2009 attended by sentinel pediatricians that collaborate with PIDIRAC. Pharyngeal and nasopharyngeal swabs for virologic analysis of suspected influenza cases were collected on a systematic basis in order to avoid bias. Every week during the study period the first two patients that consult and comply with the definition of suspicious case of influenza were recruited, if consent was obtained. Demographic characteristics and clinical features were recorded, and virologic studies were performed. The fifty-five children with confirmed pandemic influenza A (H1N1) 2009 were contacted by telephone in order to obtain information regarding their clinical status.

Results: most of the cases were 5-14 years old children and adolescents (89.1%, 95% CI 77.8-95.9). The most frequent symptoms were fever (inclusion criteria), that lasted a mean of 3.6 days (SD = 1.6) and cough. More than 50% of patients also presented with sore throw, rhinitis or headache. In general, the disease was mild even though one child was hospitalised during 48 hours because he (or she) had a pneumonia. Of the thirteen patients who suffered from asthma only two had mild exacerbations. None of the patients needed antiviral treatment.

Conclusions: despite initial fears, the cases of pandemic influenza A (H1N1) 2009 treated in our community health centres have been generally mild.