Canada communicable disease report = Releve des maladies transmissibles au Canada最新文献

Background: The coronavirus disease 2019 (COVID-19) pandemic has caused substantial disruption to in-person learning, often interfering with the social and educational experience of children and youth across North America, and frequently impacting the greater community by limiting the ability of parents and caregivers to work outside the home. Real-world evidence related to the risk of COVID-19 transmission in school settings can help inform decisions around initiating, continuing, or suspending in-person learning.

Methods: We analyzed routinely collected case-based surveillance data from Saskatchewan's electronic integrated public health system, Panorama, from the 2020-2021 school year, spanning various phases of the pandemic (including the Alpha variant wave), to better understand the risk of in-school transmission of COVID-19 in Saskatchewan schools.

Results: The majority (over 80%) of school-associated COVID-19 infections were acquired outside the school setting. This finding suggests that the non-pharmaceutical measures in place (including masking, distancing, enhanced hygiene, and cohorting) worked to limit viral spread in schools.

Conclusion: Implementation of such control measures may play an essential role in allowing children and youth to safely maintain in-person learning during the pandemic.

Background: Recombinant protein technology is a novel platform for influenza vaccine manufacturing that differs significantly from existing egg-based and mammalian cell culture-based technologies. Supemtek™ is the first and, to date, the only recombinant quadrivalent influenza vaccine (RIV4) authorized for use in Canada in adults aged 18 years and older. The objective is to review the available evidence for efficacy, effectiveness, immunogenicity and safety of RIV4, and to summarize the National Advisory Committee on Immunization (NACI) recommendation regarding the use of Supemtek.

Methods: A systematic literature review and meta-analysis on the vaccine efficacy, effectiveness, immunogenicity and safety of RIV4 in adults was conducted according to methodology specified a priori in a written protocol. NACI evidence-based process was used to assess the available evidence and develop a recommendation regarding the use of Supemtek.

Results: Ten eligible studies were included in the evidence synthesis. One randomized controlled trial (RCT) in adults aged 50 years and older provided evidence that RIV4 may potentially offer improved protection against laboratory-confirmed influenza A infection compared to standard egg-based influenza vaccines. Data from eight RCTs assessing immunogenicity and five RCTs and one post-marketing surveillance study assessing safety indicated that Supemtek is a safe, well tolerated, and immunogenic alternative to conventional egg-based influenza vaccines for adults.

Conclusion: There is fair evidence that Supemtek is effective, safe, and has non-inferior immunogenicity to comparable vaccines, based on direct evidence in adults 18 years of age and older; thus, NACI recommends that Supemtek may be considered among the seasonal influenza vaccines offered to adults 18 years of age and older for their annual influenza vaccination.

Background: The National Advisory Committee on Immunization (NACI) reviews the evolving evidence on influenza immunization and provides annual recommendations regarding the use of authorized seasonal influenza vaccines to the Public Health Agency of Canada.

Objective: To summarize the NACI seasonal influenza vaccine recommendations for 2022-2023 and to highlight new recommendations and supporting evidence.

Methods: In the preparation of the Statement on Seasonal Influenza Vaccine for 2022-2023, NACI's Influenza Working Group followed the NACI evidence-based process for developing recommendations. The recommendations were then considered and approved by NACI in light of the available evidence.

Results: The following key updates and new recommendations have been made for the 2022-2023 season: 1) updated information/guidance on influenza vaccination in the context of the coronavirus disease 2019 (COVID-19) has been incorporated; 2) Supemtek™ recombinant influenza vaccine may be considered for use among the quadrivalent influenza vaccines offered to adults 18 years of age and older for annual influenza immunization; and 3) Flucelvax^® Quad may be considered among the quadrivalent influenza vaccines offered to adults and children two years of age and older.

Conclusion: NACI continues to recommend that an age-appropriate influenza vaccine should be offered annually for all individuals aged six months of age and older who do not have contraindications to the vaccine, with particular focus on people at high risk of influenza-related complications or hospitalization, people capable of transmitting influenza to those at high risk, and other groups for whom influenza vaccination is particularly recommended.

Background: Laboratory confirmation of influenza is not routinely done in practice. With the advent of big data, it is tempting to use healthcare administrative databases for influenza vaccine effectiveness studies, which often rely on clinical diagnosis codes. The objective of this article is to compare influenza incidence curves using international case definitions derived from clinical diagnostic codes with influenza surveillance data from the United States (US) Centers for Disease Control and Prevention (CDC).

Methods: This case series describes influenza incidence by CDC week, defined using International Classification of Disease diagnostic codes over four influenza seasons (2015-2016 to 2018-2019) in a cohort of US individuals three years of age and older who consulted at least once per year between 2015 and 2019. Results were compared to the number of influenza-positive specimens or outpatient visits for influenza-like illness obtained from the CDC flu surveillance data.

Results: The incidence curves of influenza-related medical encounters were very similar to the CDC's surveillance data for laboratory-confirmed influenza. Conversely, the number of influenza-like illness encounters was high when influenza viruses started to circulate, leading to a discrepancy with CDC-reported data.

Conclusion: A specific case definition should be prioritized when data for laboratory-confirmed influenza are not available, as a broader case definition would conservatively bias influenza vaccine effectiveness toward the null.

Background: Invasive pneumococcal disease (IPD), which is caused by Streptococcus pneumoniae, has been a nationally notifiable disease in Canada since 2000. The use of conjugate vaccines has markedly decreased the incidence of IPD in Canada; however, the distribution of serotypes has shifted in favour of non-vaccine types. This report summarizes the demographics, serotypes and antimicrobial resistance of IPD infections in Canada in 2020.

Methods: The Public Health Agency of Canada's National Microbiology Laboratory (Winnipeg, Manitoba) collaborates with provincial and territorial public health laboratories to conduct national surveillance of IPD. A total of 2,108 IPD isolates were reported in 2020. Serotyping was performed by Quellung reaction and antimicrobial susceptibilities were determined in collaboration with the University of Manitoba/Canadian Antimicrobial Resistance Alliance. Population-based IPD incidence rates were obtained through the Canadian Notifiable Disease Surveillance System.

Results: Overall incidence of IPD in Canada decreased significantly from 11.5 (95% confidence interval [CI]: 10.1-13.1) to 6.0 (95% CI: 5.0-7.2), and from 10.0 (95% CI: 9.7-10.3) to 5.9 (95% CI: 5.7-6.2) cases per 100,000 from 2019 to 2020; in those younger than five years and those five years and older, respectively. The most common serotypes overall were 4 (11.2%, n=237), 3 (10.9%, n=229) and 8 (7.2%, n=151). From 2016 to 2020, serotypes with increasing trends (p<0.05) included 4 (6.4%-11.2%), 3 (9.5%-10.9%), 8 (5.2%-7.2%) and 12F (3.6%-5.7%). The overall prevalence of PCV13 serotypes increased over the same period (30.3%-34.9%, p<0.05). Antimicrobial resistance rates in 2020 included 23.0% clarithromycin and 9.9% penicillin (IV meningitis breakpoints). Multidrug-resistant IPD has significantly increased since 2016 (4.2%-9.5%, p<0.05).

Conclusion: Though the incidence of IPD decreased in 2020 in comparison to previous years across all age groups, disease due to PCV13 serotypes 3 and 4, as well as non-PCV13 serotypes such as 8 and 12F, increased in prevalence. Continued surveillance of IPD is imperative to monitor shifts in serotype distribution and antimicrobial resistance.

Background: Direct-acting antivirals (DAAs) are curative treatments for hepatitis C virus (HCV) infection, a condition affecting over 100,000 Ontarians. Although DAAs are covered under the public drug programs in Ontario, receiving prescriptions depends on access to healthcare. The aim of this study is to understand the relationship between DAA treatment rates and distance to prescriber in Ontario, Canada.

Methods: We conducted a cross-sectional study and identified patients who filled a DAA prescription through the Ontario Drug Benefit (ODB) in 2019. We calculated crude (per 100,000 ODB recipients) and adjusted (by a regional HCV infection rate) DAA treatment rates by public health unit (PHU). We reported median distances to provider for all visit types, in-person visits, virtual visits, and proportions of visits that were virtual.

Results: In 2019, the crude DAA treatment rate for Ontario is 83.0 patients per 100,000 ODB recipients. The HCV-adjusted DAA treatment rate ranges from 28.2 (Northwestern Ontario) to 188.5 (Eastern Ontario) per 100,000. In our primary analysis, patients in rural PHUs, including Northwestern and Porcupine, were among the highest median distances to prescriber for all visit types (1,195 km and 556 km, respectively). These PHUs also had the highest proportions of virtual visits (greater than 60%). Urban PHUs, such as Toronto and Ottawa, had smaller median distances for all visit types, with smaller proportions of virtual visits (10.8% and 12.4%, respectively).

Conclusion: We observed heterogeneity in treatment rates, distance to DAA prescribers and use of virtual care in the management of HCV. Increasing use of telemedicine in regions with limited utilization of DAAs may improve access.