Positive predictive value of respiratory infection diagnoses in the Danish National Patient Registry: A post hoc validation analysis of the DANFLU-1 trial. - Christensen J; Johansen ND; Bernholm KF; Borchsenius JIH; Janstrup KH; Modin D; Skaarup KG; Nealon J; Samson S; Loiacono M; Huang Y; Harris R; et al. (International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases, 2026)