Region of Waterloo Public Health and Emergency Services Local Influenza Surveillance Bulletin Released October 31, 2016 Current Assessment of Influenza Activity in Waterloo Region As of October 31, 2016, there have been 4 laboratory confirmed cases of influenza (2 influenza A and 2 influenza B) and 0 institutional influenza outbreaks reported in Waterloo Region this season. Among laboratory-confirmed cases of influenza in Waterloo Region, there has been 1 hospitalization 1 and 0 deaths. 2 To date, 1 case has been travel-related and 3 cases were locally acquired. Influenza Activity: August 28, 2016 to October 22, 2016 (Weeks 35 to 42) Figure 1: Number of reported 3 laboratory confirmed cases of influenza by week and type, Waterloo Region, August 28, 2016 to October 22, 2016 4 Source: iphis, Ministry of Health and Long-Term Care (MOHLTC), extracted October 31, 2016 Alternate text: The figure displays the weekly count of influenza A and B cases for Waterloo Region. As of week 42, there have been 2 cases of influenza A and 2 cases of influenza B. 1 In the 2016-2017 season, only a proportion of laboratory confirmed cases are being followed up by public health units; therefore, the number of hospitalized cases may not be representative of the true burden of illness in the Waterloo Region population due to possible underreporting. 2 Includes deaths where influenza was the underlying cause, and where influenza was a contributing factor, but not the underlying cause. In the 2016-2017 season, only a proportion of laboratory confirmed cases are being followed up by public health units; therefore, the number of deaths may not be representative of the true burden of illness in the Waterloo Region population due to possible underreporting. 3 Reported laboratory confirmed cases are based on case reported date which needs to be interpreted with caution due to the lag between the onset of illness, hospital admission, or death and reporting of the infection to public health. 4 The week numbers referenced throughout the bulletin refer to FluWatch weeks, which are established by the Public Health Agency of Canada. 1
Figure 2: Rates 5 of reported laboratory confirmed cases of influenza by week, Waterloo Region and Ontario, 2011-2012 to 2016-2017 Source: iphis, MOHLTC, extracted October 31, 2016. Ontario Respiratory Pathogen Bulletin: Week 42. Population estimates (2011-2016), 2011 Census (Table 109-5355), Statistics Canada, extracted April 26, 2016. Alternate text: The figure displays the weekly occurrence of new cases per 100,000 persons at risk in Waterloo Region and Ontario. The week 42 rate for Waterloo Region is 0.18. The week 42 rate for Ontario is 0.08. Influenza rates in Waterloo Region are higher than Ontario's. Table 1: Number of reported laboratory confirmed influenza cases and incidence rates, by age group, Waterloo Region, August 28, 2016 to October 22, 2016 Age Group Number of cases Age-specific Rate per 100,000 0 to 19 1 0.78 20 to 64 2 0.58 65+ 1 1.27 Source: iphis, MOHLTC, extracted October 31, 2016. Population estimates (2011-2016), 2011 Census (Table 109-5355), Statistics Canada, extracted April 26, 2016. Alternate text: The table displays the cumulative number and age-specific rate per 100,000 of confirmed cases by age group for Waterloo Region. As of week 42, there has been 1 case (0.78 per 100,000) aged 0 to 19, 2 cases (0.58 per 100,000) aged 20 to 64, and 1 case (1.27 per 100,000) aged 65 and older. 5 Crude rates are presented throughout the bulletin, and thus are not age-standardized. Caution should be used when comparing crude rates across different geographical areas (i.e., Waterloo Region and Ontario), because part of the difference may be attributable to the differences in age distribution between the two populations. 2
Table 2: Influenza indicators, Waterloo Region and Ontario, August 28, 2016 to October 22, 2016 Waterloo Region Ontario Indicator Number Rate per 100,000 Number Rate per 100,000 Laboratory confirmed cases 4 0.73 60 0.43 Hospitalized confirmed cases 6 1 0.18 15 0.11 Deaths among confirmed cases 7 0 0.00 0 0.00 Institutional outbreaks 8 0 NA 3 NA Source: iphis, MOHLTC, extracted October 31, 2016. Ontario Respiratory Pathogen Bulletin: Week 42. Population estimates (2011-2016), 2011 Census (Table 109-5355), Statistics Canada, extracted April 26, 2016. Alternate text: The table displays the cumulative number and rate of confirmed cases, hospitalized cases, deaths, and institutional outbreaks for Waterloo Region and Ontario. As of week 42, have been 4 confirmed cases (0.73 per 100,000), 1 hospitalized case (0.18 per 100,000), 0 deaths (0.00 per 100,000), and 0 institutional outbreaks in Waterloo Region, while there have been 60 confirmed cases (0.43 per 100,000), 15 hospitalizations (0.11 per 100,000), 0 deaths (0.00 per 100,000), and 3 institutional outbreaks in Ontario. School Absenteeism Surveillance School Absenteeism Monitoring school absenteeism rates is an indicator of the level of community transmission of influenza. An absenteeism rate of 10 per cent or greater has been identified as a threshold by the Ministry of Health and Long Term Care (MOHLTC) to signify higher than expected levels of school absenteeism. The figure below shows the per cent absent of all schools, the average per cent absent of the previous five years of all schools in Waterloo Region by week, the overall average absenteeism of the previous five years, and the overall average of the previous five years plus two standard deviations. 6 In the 2016-2017 season, only a proportion (20 per cent) of laboratory confirmed cases are being followed up by public health units; therefore, the number of hospitalized cases may not be representative of the true burden of illness in the Waterloo Region and Ontario population due to possible underreporting. 7 Includes deaths where influenza was the underlying cause, and where influenza was a contributing factor, but not the underlying cause. In the 2016-2017 season, only a proportion (20 per cent) of laboratory confirmed cases are being followed up by public health units; therefore, the number of deaths may not be representative of the true burden of illness in the Waterloo Region and Ontario population due to possible underreporting. 8 The number of outbreaks reported is based on the onset date of illness for the first case in an outbreak meeting the provincial outbreak definition. 3
Figure 3: School Absenteeism, Waterloo Region, August 28, 2016 to October 21, 2016 *Indicates incomplete/partial data due to school closure (e.g. PA day, secondary school exams, statutory holiday, school break, or snow day). Source: Waterloo Region District and Catholic School Boards, extracted October 31, 2016. Alternate text: The figure displays the weekly proportion of students absent from Waterloo Region schools. Absenteeism for week 42 was 2.2 per cent which is lower than the 5-year historical average of 2.3 for week 42. Canada Influenza Strain Characterization In order to determine how well the influenza vaccine recommendations from the World Health Organization (WHO) for the 2016-2017 season match with the influenza strains exhibited in the population, Figure 4 shows the breakdown of influenza strains in Canada to date. The recommended components for the 2016-2017 northern hemisphere trivalent influenza vaccine include: A/California/7/2009(H1N1)pdm09-like virus, A/Hong Kong/4801/2014 (H3N2)-like virus, and B/Brisbane/60/2008-like virus. For quadrivalent vaccines, the addition of B/Phuket/3073/2013-like virus is recommended by the WHO. Canada authorized quadrivalent vaccines as of July 2014. Figure 4: Strain characterization completed on influenza isolates at the National Microbiology Laboratory: Canada, 2016-2017 Season, N = 34 Source: Influenza and Respiratory Viruses Section, National Microbiology Laboratory (NML); Public Health Agency of Canada (PHAC); FluWatch Bulletin: Week 42 Alternate text: The figure displays the weekly proportion of Canadian influenza cases by strain. As of week 42, A/Hong Kong/4801/2014-like is the dominant strain in circulation with 85% of characterized isolates. 4
Provincial and National Influenza Surveillance For more information on influenza for the 2016-2017 season, please visit the following websites: Public Health Ontario, Ontario Respiratory Pathogen Bulletins: http://www.publichealthontario.ca/en/servicesandtools/surveillanceservices/pages/ Ontario-Respiratory-Virus-Bulletin.aspx Public Health Agency of Canada, FluWatch Reports: http://healthycanadians.gc.ca/diseases-conditions-maladies-affections/disease-maladie/flu-grippe/ surveillance/fluwatch-reports-rapports-surveillance-influenza-eng.php Contact Information Region of Waterloo Public Health and Emergency Services Epidemiology and Health Analytics Team 99 Regina Street South, Third Floor Waterloo, Ontario, N2J 4V3 Canada Phone: 519-575-4400 Fax: 519-883-2241 TTY: 519-575-4608 Website: www.region.waterloo.on.ca/ph Email: eha@regionofwaterloo.ca Accessible formats of this document are available upon request. Please call the Coordinator, Marketing and Communications at 519-575-4400 ext. 2244, (TTY 519-575-4608) to request an accessible format. Internal access to report: DOCS #2229399 The Epidemiology and Health Analytics Team would like to express thanks to all of the local influenza partners for their contributions to this year s influenza surveillance program. 5