CI, confidence interval; cp, copies; CRISPR, clustered regularly interspaced short palindromic repeats; Ct, cycle threshold; LAMP, isothermal loop-mediated amplification; NAAT, nucleic acid amplification test; NDU, NAAT detectable units; NP, nasal pharyngeal; RNA, ribonucleic acid; RT-PCR, reverse transcription polymerase chain reaction; TMA, transcription-mediated amplification.