Children should find the sampling procedure for acute respiratory infection much less painful, after a small study has shown for the first time that nasal swabs are suitable and provoke much less discomfort than nasopharyngeal swabs.
Detection of influenza virus was very similar for nasal swabs and nasopharyngeal swabs by direct immunofluorescence (27% v 29% positive, respectively) and enzyme assay (26% v 28% positive). Detection of respiratory syncytial virus was identical, at 20% for both samples. The difference in sensitivity and specificity of nasal and nasopharyngeal swabs and in their positive and negative predictive values was negligible or non-existent.
Pain scores according to crying time (25 children), or assessment by Oucher score (12) or facial coding (14) were all significantly lower with nasal swabs.
Paired samples were obtained with a lower nasal swab and a high nasopharyngeal swab from opposite nostrils of 199 children (median age 1.5 years, range 11 days–13.8 years) with suspected acute respiratory infection. Each was examined by direct immunofluorescence and enzyme assay for influenza and by direct immunofluorescence for respiratory syncytial virus. Pain was measured by duration of crying for children aged under 3 years or by standard Oucher pain scale and a validated facial coding system in older children.
Acute respiratory infection is the commonest cause of childhood illness. One recent study found these two sampling methods equally effective for detecting influenza virus, though the pain they cause has not been studied before.
▴ Archives of Disease in Childhood 2002;86:372–373.