Anterior nasal swabs compared to nasopharyngeal swabs for detection of respiratory viruses in children

Respiratory viral testing often uses invasive nasopharyngeal (NP) swabs, which can be painful and require trained personnel. Anterior nasal swabs (NS) are less invasive and can be self-collected. The sensitivity of NS compared to NP specimens for detecting multiple respiratory viruses in children are not well described. Hospitalized children in Kansas City, MO, from January 2023 to February 2024, who had NP specimens obtained for standard of care multiplex respiratory viral testing in the previous 72 h, were enrolled. NS specimens were collected and tested alongside salvaged NP specimens for adenovirus, seasonal coronaviruses, human metapneumovirus, respiratory syncytial virus, influenza, rhinovirus/enterovirus, SARS-CoV-2, and parainfluenza viruses using multiplex molecular testing. Concordance, sensitivity, and specificity of NS compared to NP specimens were assessed. A total of 147 paired NP/NS specimens were analyzed. Overall, 114 (77.6 %) NP/NS pairs were concordant, including 86 (58.5 %) virus-positive and 28 (19.1 %) virus-negative pairs. NS sensitivity was 84.3 % compared to NP, increasing to 95.7 % when collected within 24 h of NP specimens. Sensitivity for seasonal coronavirus was poor (36.4 %), but was over 75 % for other viruses, and 100 % for adenovirus, influenza, parainfluenza, RSV, and SARS-CoV-2 within 24 h of NP specimens. Virus cycle threshold counts were similar among paired specimens. NS specimens showed good concordance with NP specimens and high sensitivity for most viruses, except seasonal coronavirus. NS testing may enable respiratory virus monitoring outside medical settings.