Nasal discharge: A unique enhanced alternative for the detection of respiratory pathogens in adults

Upper respiratory tract infections are a significant cause of social- and disease burden worldwide. Currently, invasive and uncomfortable molecular detection methods are used for respiratory pathogen detection. We aimed to assess the ability and bearability of a rhinorrhea swab (RS) to detect respiratory pathogens in comparison to the combined nasopharyngeal and oropharyngeal swab (NP/OP). This study was performed at a Public Health Service severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) testing facility between November and December 2022 in the Netherlands. Adults aged 16 years and older, being subjected to a standard of care NP/OP swab with nasal discharge, were included and received an additional RS. Respiratory pathogen detection was evaluated using SARS-CoV-2 polymerase chain reaction (PCR) and multiplex ligation-dependent probe amplification (MLPA) PCR. Bearability was evaluated using visual analog scale (VAS) scores and a questionnaire. A total of 100 adults with a mean age ± SD of 46 ± 16 years were included. The NP/OP swab detected 104 pathogens, the RS 83 pathogens (p < 0.001), and in total 108 respiratory pathogens were identified in 89 adults (89%). The ability to detect respiratory pathogens compared between the RS and the combined NP/OP swab revealed a sensitivity of 82% (95% CI 73%-89%) and specificity of 100% (95% CI 72%-100%). RS were significantly more bearable than the combined NP/OP swab (p value < 0.001). Therefore, nasal discharge found in adults can be used as an adequate reliable medium for respiratory pathogen detection using SARS-CoV-2 PCR and MLPA PCR.