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

Background: In April of 2024, studies in the United States (US) identified the presence of influenza A(H5N1) viral RNA in 20%-40% of commercially available pasteurized milk in the US, suggesting that cattle infections were widespread across the country.

Methods: As an initial assessment of the situation in Ontario, 117 samples of pasteurized cow's milk purchased from retail outlets in Ontario in April and May of 2024 were tested for the presence of influenza A viral RNA.

Results: No influenza A viral RNA was detected.

Conclusion: The Canadian Food Inspection Agency has subsequently developed an ongoing surveillance system for testing commercially available pasteurized milk and raw milk at processing plants in Canada.

Background: Over the past ten years, there has been a steady increase in the reported rates of gonorrhea and chlamydia in Canada, with gonorrhea rising by 171% and chlamydia by 26%.

Objective: To collect and synthesize national and international chlamydia and gonorrhea screening guidelines to inform the revision of the current Public Health Agency of Canada (PHAC) recommendations.

Methods: A scan of published chlamydia and gonorrhea screening guidelines of high-income countries was conducted. Guidelines were appraised using the Appraisal of Guidelines for Research & Evaluation II (AGREE II) and PROGRESS-Plus tools.

Results: A total of 17 guidelines on chlamydia and gonorrhea screening published between 2015 and 2023 were included in this review. The overall score of the AGREE II methodological assessment ranged from a rating of three to seven out of seven points. Only one guideline fully met the considerations identified in the assessment tool. Most international organizations recommend universal screening for chlamydia, and a few organizations recommend opportunistic screening and targeted/risk-based screening. As for gonorrhea screening, organizations mostly recommend targeted/risk-based screening and a few organizations recommend universal screening. None of the international gonorrhea guidelines recommended opportunistic screening. The implementation of universal screening has been shown to have minimal negative impact on the individuals being screened, while increasing testing rates. Most guidelines recommend screening individuals <25 years of age, while only two organizations recommend screening individuals <30 years of age.

Conclusion: The findings of this review will be used to inform the revision of the current PHAC recommendations on chlamydia and gonorrhea screening, which will be published in early 2025. International organizations recommend either universal or opportunistic screening. The majority of Canadian provinces and territories follow PHAC's Sexually Transmitted and Blood-Borne Infections: Guides for Health Professionals and recommend universal screening for individuals <25 years of age.

Background: In Canada, gonorrhea is the second most prevalent sexually transmitted bacterial infection. The Gonococcal Antimicrobial Surveillance Programme-Canada (GASP-Canada), a passive surveillance system monitoring antimicrobial resistance in Neisseria gonorrhoeae in Canada since 1985, is the source for this summary of demographics, antimicrobial resistance and N. gonorrhoeae multi-antigen sequence typing (NG-MAST) of gonococcal isolates collected in Canada in 2022.

Objective: To summarize the antimicrobial resistance trends and molecular types of N. gonorrhoeae cultures in Canada from 2018 to 2022. These trends inform the federal, provincial and territorial guidelines for treatment of gonorrhea.

Methods: Provincial and territorial public health laboratories submitted N. gonorrhoeae cultures and data to the National Microbiology Laboratory in Winnipeg as part of the surveillance system. The antimicrobial resistance and molecular type of each isolate received were determined.

Results: In total, 3,855 N. gonorrhoeae cultures were identified and tested across Canada in 2022, a 12.1% increase since 2021 (n=3,439). Decreased susceptibility to cefixime declined in 2022 (0.3%) compared to 2018 (0.5%). Decreased susceptibility to ceftriaxone also declined between 2018 (0.6%) and 2022 (0.3%). Azithromycin resistance was similar in 2022 (8.1%) to what it was in 2018 (7.6%). In 2022, NG-MAST-17972 (13.3%) was the most prevalent sequence type in Canada.

Conclusion: The spread of antimicrobial-resistant gonorrhea is a significant public health concern. The continued regional and national surveillance of antimicrobial resistance in N. gonorrhoeae is essential in ensuring effective treatment therapies are recommended.

Background: A variety of methods, including self-report and antibody testing, has been used to estimate the prevalence of SARS-CoV-2 infections and related longer-term symptoms, but the impact of employed methods on conclusions has not been thoroughly explored.

Objective: We examined associations between self-report and antibody findings in the Canadian adult (aged 18 years and older) population.

Methods: We used data from a large population-based cross-sectional probability survey conducted between April and August 2022. Self-reported infection status and experiences with common longer-term COVID-19 symptoms since the start of the pandemic was collected, as well as a dried blood spot to measure SARS-CoV-2 antibodies.

Results: As of August 2022, the number of adults reported having had a confirmed or suspected infection was 37.9% (95% CI: 36.8%-39.1%), while the overall mean probability of having infection-related antibodies was 52.9% (95% CI: 51.8%-54.0%) and increased with respondent certainty they had been infected. However, the mean probability of having infection-related antibodies was not associated with infection severity or the reporting of common longer-term COVID-19 symptoms. More than one in five adults were unaware they had been infected.

Conclusion: Self-report surveys may misclassify the SARS-CoV-2 infection status of a substantial proportion of untested people and may bias estimates of the percentage infected, the severity of infections and the risk of developing infection-related longer-term symptoms. Common longer-term COVID-19 symptoms reported by some could have been caused by other infections or diseases.

Background: Immunization programs for the prevention of respiratory syncytial virus (RSV) in infants have been available in Canada since the authorization of palivizumab in 2002. However, these programs have been limited to only those infants at highest risk for severe RSV disease. The authorization of new passive immunizing products to prevent RSV, including a new monoclonal antibody (nirsevimab) and a vaccine administered in pregnancy (RSV pre-fusion stabilized F protein; RSVpreF) offers the opportunity to prevent RSV in more Canadian infants. The objective of this article is to summarize guidance from the National Advisory Committee on Immunization (NACI) on the prevention of RSV in infants.

Methods: NACI established key policy questions and performed an evidence review and synthesis. NACI made evidence-based recommendations in consideration of the burden of illness to be prevented, safety and efficacy of the new immunizing products, economic evidence and ethics, equity, feasibility, and acceptability.

Results: Nirsevimab and RSVpreF offer protection against severe outcomes of RSV disease, including hospitalization and intensive care unit admission. Nirsevimab protection may be slightly higher and may last longer than protection offered by RSVpreF. Nirsevimab and RSVpreF also have a similar frequency of adverse reactions for both pregnant and infant participants. The RSVpreF vaccine may increase the risk of severe local adverse events compared to placebo for pregnant recipients. In RSVpreF clinical trials, an imbalance was observed in late preterm birth between RSVpreF and placebo recipients. It is unclear whether there is a causal relation with the vaccine as the currently available data is inconclusive.

Conclusion: Based on new evidence, NACI recommends building towards a universal RSV immunization program for all infants. Currently, nirsevimab is preferred over RSVpreF. Program introduction could occur in stages depending on access to supply, cost effectiveness, and affordability of available options.

Background: The Global Public Health Intelligence Network (GPHIN) is an event-based surveillance platform that collects thousands of pieces of open-source information, including international news media, across multiple languages on a daily basis. Analysts have observed that news media reporting in some languages tended to use more sensational wording to describe major health events. There has been minimal research exploring potential differences in sensationalism in international news media reporting to confirm these observations.

Objective: This exploratory study assessed the differences in the level of sensationalism in early international news media reporting of COVID-19 through a mixed-methods analysis.

Methods: Relevant news media articles received in GPHIN seven days following the Public Health Emergency of International Concern declaration of COVID-19 by the World Health Organization were extracted for screening and analysis. An adapted tool was used to measure the sensationalism of pandemic-related health news. Deductive thematic analysis was conducted to examine themes of sensationalism. Differences in prevalence of sensationalism in news media reporting by language and country/territory of publication were assessed. Sentiment analysis assessed the sentiment and emotional tone of the news media articles.

Results: Of 951 news articles that met the eligibility criteria, 155 contained sensationalism. There were significant differences between languages (French, Russian and Spanish) and various domains of sensationalism. This study also found a more negative emotional tone in news media articles with sensationalism.

Conclusion: This exploratory study showed that language has the potential to impact the perception of health events using more sensationalized language.

Background: In July 2024, Health Canada authorized a 21-valent pneumococcal conjugate vaccine (Pneu-C-21) for use in adults.

Objective: To conduct a systematic review of the cost-effectiveness of Pneu-C-21 for preventing pneumococcal disease in adults.

Methods: We conducted a systematic search of the literature and National Immunization Technical Advisory Groups' websites on July 3, 2024. We included economic evaluations that assessed Pneu-C-21 as a vaccination strategy among adults aged 18 years and older. Costs were adjusted to 2023 Canadian dollars.

Results: We identified 10 studies in our search, five of which were summarized in our review. No economic evaluations were conducted in Canada. All economic evaluations used static cohort models and incorporated indirect effects from paediatric pneumococcal conjugate vaccination in primary or sensitivity analyses. Although incremental cost-effectiveness ratios were heterogeneous across included economic evaluations, overall, they qualitatively identified the same vaccination strategies as optimal within the given age and risk groups. Pneu-C-21 is likely to be cost-effective in adults aged 65 years and older and adults under the age of 65 years with specific high risk conditions.

Conclusion: Pneu-C-21 is likely to be cost-effective in adults within specific age and risk groups. The applicability of the included economic evaluations to adults living in Canada is limited because the serotype-specific incidence of pneumococcal disease and the impact of indirect effects from pediatric vaccination varies by region and over time.

Background: Two pneumococcal conjugate vaccines, covering 15 and 20 Streptococcus pneumoniae serotypes (Pneu-C-15 and Pneu-C-20, respectively), were recently approved for use in the Canadian paediatric population.

Objective: To assess the cost-effectiveness of Pneu-C-15 and Pneu-C-20 in unvaccinated infants initiating routine pneumococcal vaccination, compared to the currently used 13-valent conjugate vaccine (Pneu-C-13).

Methods: A static cohort model was used to estimate sequential incremental cost-effectiveness ratios (ICERs in 2022 Canadian dollars per quality-adjusted life year [QALY]) of Pneu-C-13, Pneu-C-15 and Pneu-C-20 in the paediatric population starting their primary series. Costs and outcomes were calculated over a 10-year time horizon at the program level and a lifetime time horizon at the individual level and discounted at a rate of 1.5% per year. We explored the impact of uncertainties in model parameters and assumptions in scenario and sensitivity analyses.

Results: Routine use of Pneu-C-20 and, to a lesser extent, Pneu-C-15 is projected to reduce pneumococcal disease burden, compared to Pneu-C-13. Based on product cost assumptions, sequential ICERs for Pneu-C-15 and Pneu-C-20 were $58,800 and $135,200 per QALY gained from the health system perspective and $18,272 and $93,416 per QALY gained from the societal perspective, excluding indirect effects. A reduction in serotype-attributable disease due to indirect vaccine effects of 5% or greater resulted in ICERs below $30,000 per QALY gained for Pneu-C-15 and Pneu-C-20, with the optimal strategy determined by the magnitude and time to reach a reduction in pneumococcal disease.

Conclusion: Both Pneu-C-15 and Pneu-C-20 are expected to increase QALYs in Canadian children compared to Pneu-C-13 and may be cost-effective interventions.

Background: Mpox is an infectious disease caused by the monkeypox virus (MPXV), closely related to the virus that causes smallpox. In May 2022, cases of mpox were reported in previously non-endemic countries including Canada.

Objective: To summarize the epidemiology of the mpox outbreak in Canada, as well as key public health response activities, between April and December 2022.

Methods: The Public Health Agency of Canada (PHAC) worked closely with local, provincial and territorial public health authorities to develop national case investigation and reporting tools, including national case definitions for confirmed and probable mpox cases. Based on de-identified case data submitted to PHAC, patterns and trends were examined, including the distribution of cases by sociodemographic, clinical and transmission factors.

Results: Overall, 1,474 mpox cases (1,396 confirmed, 78 probable) were reported to PHAC. All reported cases were associated with MPXV clade IIb. Mpox disproportionately affected gay, bisexual and other men who have sex with men (80.0%) and those between 20-49 years of age (86.0%). Available data suggests that the most likely mode of disease acquisition was through sexual contact, with limited evidence on other possible modes of transmission. Some cases were hospitalized (3.0%); however, there were no mpox-related deaths in Canada.

Conclusion: Rapid coordination and surveillance activities supported the timely implementation of tailored interventions, including the procurement and distribution of vaccines. These actions, coupled with vaccination uptake and behavioural changes, contributed to reducing transmission and health impacts of mpox on the Canadian population.

Background: Two respiratory syncytial virus (RSV) vaccines are currently approved for use in adults aged 60 years and older in Canada.

Objective: To conduct a multi-model comparison to explore the impact of alternate model structural and methodological assumptions on the estimated cost-effectiveness of RSV adult vaccination programs.

Methods: We compared three static cost-utility models developed by the Public Health Agency of Canada, GSK and Pfizer using a common set of input parameters. Each model evaluated sequential incremental cost-effectiveness ratios in 2023 Canadian dollars per quality-adjusted life year (QALY) for a set of policy alternatives, with vaccine eligibility determined by combinations of age and chronic medical condition (CMC) status. Results were calculated for each vaccine separately for scenarios assuming two or three years of vaccine protection using the health system perspective and a 1.5% annual discount rate.

Results: The three cost-utility models were broadly concordant across the scenarios modeled. In all scenarios, focusing on vaccination of people with CMCs was preferred over broader age-based policies. Respiratory syncytial virus vaccination for people with CMCs over the age of 70 years was most commonly identified as the optimal policy when using a cost-effectiveness threshold of $50,000/QALY. When only considering policies based on age criteria, vaccinating people over 80 years was cost-effective at this threshold.

Conclusion: A multi-model comparison of Canadian cost-utility models shows that RSV vaccination programs for RSV are likely cost-effective for some groups of older adults in Canada. These findings were consistent across models, despite differences in model structure.