Figure.
Influenza detections among specimens collected from eligible patients presenting with influenza-like illness, by week of specimen collection, Canadian Sentinel Practitioner Surveillance Network, 1 November 2019–1 February 2020 (n = 2,811a)
a The epidemic curve includes three influenza A and B co-infections, two involving influenza A(H1N1)pdm09 plus influenza B and one involving influenza A of unknown subtype plus influenza B. These six viruses from three specimens are each plotted separately giving 2,811 displayed specimens rather than 2,808.
Missing specimen collection dates were imputed as the date the specimen was received and processed at the provincial laboratory minus 2 days.