Table 2.

Evidence for nosocomial transmission of influenza using classical and genetic methods, University College London Hospitals NHS Foundation Trust, 2012‐2014 (n = 214)

Classical definitiona	Genetic definitionb
	Hospital‐acquired (n = 34)		Community‐acquired (n = 180)
	n	%c	n	%
Hospital‐acquired (n = 32)	14	43.8	18	56.3
Community‐acquired (n = 182)	20	11.0	162	89.0

^aCases defined as hospital‐acquired if PCR‐positive influenza sample was taken more than two days after admission; and as community‐acquired if taken within two days.

^bCases defined as hospital‐acquired if they were part of a genetically defined cluster (except the first case to be identified in the cluster, classified as the “index” case); and as community‐acquired if they were index cases or had unique genetic strains.

^cRow percentages