BACKGROUND: The first coronavirus disease 2019 (COVID-19) case was reported in Canada on January 25, 2020. In response to the imminent outbreak, many provincial and territorial health authorities implemented nonpharmaceutical public health measures to curb the spread of disease. "Social distancing" measures included restrictions on group gatherings; cancellation of sports, cultural and religious events and gatherings; recommended physical distancing between people; school and daycare closures; reductions in non-essential services; and closures of businesses. OBJECTIVES: To evaluate the impact of the combined nonpharmaceutical interventions imposed in March 2020 on influenza A and B epidemiology by comparing national laboratory surveillance data from the intervention period with 9-year historical influenza season control data. METHODS: We obtained epidemiologic data on laboratory influenza A and B detections and test volumes from the Canadian national influenza surveillance system for the epidemiologic period December 29, 2019 (epidemiologic week 1) through May 2, 2020 (epidemiologic week 18). COVID-19-related social distancing measures were implemented in Canada from epidemiologic week 10 of this period. We compared influenza A and B laboratory detections and test volumes and trends in detection during the 2019-20 influenza season with those of the previous nine influenza seasons for evidence of changes in epidemiologic trends. RESULTS: While influenza detections the week prior to the implementation of social distancing measures did not differ statistically from the previous nine seasons, a steep decline in positivity occurred between epidemiologic weeks 10 and 14 (March 8-April 4, 2020). Both the percent positive on week 14 (p≤0.001) and rate of decline between weeks 10 and 14 (p=0.003) were significantly different from mean historical data. CONCLUSION: The data show a dramatic decrease in influenza A and B laboratory detections concurrent with social distancing measures and nonpharmaceutical interventions in Canada. The impact of these measures on influenza transmission may be generalizable to other respiratory viral illnesses during the study period, including COVID-19.
BACKGROUND: The first coronavirus disease 2019 (COVID-19) case was reported in Canada on January 25, 2020. In response to the imminent outbreak, many provincial and territorial health authorities implemented nonpharmaceutical public health measures to curb the spread of disease. "Social distancing" measures included restrictions on group gatherings; cancellation of sports, cultural and religious events and gatherings; recommended physical distancing between people; school and daycare closures; reductions in non-essential services; and closures of businesses. OBJECTIVES: To evaluate the impact of the combined nonpharmaceutical interventions imposed in March 2020 on influenza A and B epidemiology by comparing national laboratory surveillance data from the intervention period with 9-year historical influenza season control data. METHODS: We obtained epidemiologic data on laboratory influenza A and B detections and test volumes from the Canadian national influenza surveillance system for the epidemiologic period December 29, 2019 (epidemiologic week 1) through May 2, 2020 (epidemiologic week 18). COVID-19-related social distancing measures were implemented in Canada from epidemiologic week 10 of this period. We compared influenza A and B laboratory detections and test volumes and trends in detection during the 2019-20 influenza season with those of the previous nine influenza seasons for evidence of changes in epidemiologic trends. RESULTS: While influenza detections the week prior to the implementation of social distancing measures did not differ statistically from the previous nine seasons, a steep decline in positivity occurred between epidemiologic weeks 10 and 14 (March 8-April 4, 2020). Both the percent positive on week 14 (p≤0.001) and rate of decline between weeks 10 and 14 (p=0.003) were significantly different from mean historical data. CONCLUSION: The data show a dramatic decrease in influenza A and B laboratory detections concurrent with social distancing measures and nonpharmaceutical interventions in Canada. The impact of these measures on influenza transmission may be generalizable to other respiratory viral illnesses during the study period, including COVID-19.
Entities:
Keywords:
COVID-19; NPI; SARS-CoV-2; influenza; nonpharmaceutical interventions; physical distancing; public health; social distancing
Authors: Howard Markel; Harvey B Lipman; J Alexander Navarro; Alexandra Sloan; Joseph R Michalsen; Alexandra Minna Stern; Martin S Cetron Journal: JAMA Date: 2007-08-08 Impact factor: 56.272
Authors: Harunor Rashid; Iman Ridda; Catherine King; Matthew Begun; Hatice Tekin; James G Wood; Robert Booy Journal: Paediatr Respir Rev Date: 2014-01-31 Impact factor: 2.726
Authors: Benjamin J Cowling; Sheikh Taslim Ali; Tiffany W Y Ng; Tim K Tsang; Julian C M Li; Min Whui Fong; Qiuyan Liao; Mike Yw Kwan; So Lun Lee; Susan S Chiu; Joseph T Wu; Peng Wu; Gabriel M Leung Journal: Lancet Public Health Date: 2020-04-17
Authors: Justin Lessler; Nicholas G Reich; Ron Brookmeyer; Trish M Perl; Kenrad E Nelson; Derek A T Cummings Journal: Lancet Infect Dis Date: 2009-05 Impact factor: 25.071
Authors: Joel R Koo; Alex R Cook; Minah Park; Yinxiaohe Sun; Haoyang Sun; Jue Tao Lim; Clarence Tam; Borame L Dickens Journal: Lancet Infect Dis Date: 2020-03-23 Impact factor: 25.071
Authors: Chand S Mangat; Michael G Becker; Jade Daigle; Kathleen Racher; Justin Hazenberg; Allan Yeoman; Heather Hannah; Diep Duong; Umar Mohammed; Dave Spreitzer; Branden S J Gregorchuk; Breanne M Head; Adrienne F A Meyers; Paul A Sandstrom; Anil Nichani; James I Brooks; Michael R Mulvey Journal: Appl Environ Microbiol Date: 2022-01-05 Impact factor: 4.792