Estimating the impacts of nonoptimal temperatures on mortality: A study in British Columbia, Canada, 2001-2021.

Background: Studies show that more than 5.1 million deaths annually are attributed to nonoptimal temperatures, including extreme cold and extreme heat. However, those studies mostly report average estimates across large geographical areas. The health risks attributed to nonoptimal temperatures in British Columbia (BC) are reported incompletely or limit the study area to urban centers. In this study, we aim to estimate the attributable deaths linked to nonoptimal temperatures in all five regional health authorities (RHAs) of BC from 2001 to 2021. Methods: We applied the widely used distributed lag nonlinear modeling approach to estimate temperature-mortality association in the RHAs of BC, using daily all-cause deaths and 1 × 1 km gridded daily mean temperature. We evaluated the model by comparing the model-estimated attributable number of deaths during the 2021 heat dome to the number of heat-related deaths confirmed by the British Columbia Coroners Service. Results: Overall, between 2001 and 2021, we estimate that 7.17% (95% empirical confidence interval = 3.15, 10.32) of deaths in BC were attributed to nonoptimal temperatures, the majority of which are attributed to cold. On average, the mortality rates attributable to moderate cold, moderate heat, extreme cold, and extreme heat were 47.04 (95% confidence interval [CI] = 45.83, 48.26), 0.94 (95% CI = 0.81, 1.08), 2.88 (95% CI = 2.05, 3.71), and 3.10 (95% CI = 1.79, 4.4) per 100,000 population per year, respectively. Conclusions: Our results show significant spatial variability in deaths attributable to nonoptimal temperatures across BC. We find that the effect of extreme temperatures is significantly less compared to milder nonoptimal temperatures between 2001 and 2021. However, the increased contribution of extreme heat cannot be ruled out in the near future.

Risk of hospital admission and death from first-ever SARS-CoV-2 infection by age group during the Delta and Omicron periods in British Columbia, Canada.

BACKGROUND: Population-based cross-sectional serosurveys within the Lower Mainland, British Columbia, Canada, showed about 10%, 40% and 60% of residents were infected with SARS-CoV-2 by the sixth (September 2021), seventh (March 2022) and eighth (July 2022) serosurveys. We conducted the ninth (December 2022) and tenth (July 2023) serosurveys and sought to assess risk of severe outcomes from a first-ever SARS-CoV-2 infection during intersurvey periods. METHODS: Using increments in cumulative infection-induced seroprevalence, population census, discharge abstract and vital statistics data sets, we estimated infection hospitalization and fatality ratios (IHRs and IFRs) by age and sex for the sixth to seventh (Delta/Omicron-BA.1), seventh to eighth (Omicron-BA.2/BA.5) and eighth to ninth (Omicron-BA.5/BQ.1) intersurvey periods. As derived, IHR and IFR estimates represent the risk of severe outcome from a first-ever SARS-CoV-2 infection acquired during the specified intersurvey period. RESULTS: The cumulative infection-induced seroprevalence was 74% by December 2022 and 79% by July 2023, exceeding 80% among adults younger than 50 years but remaining less than 60% among those aged 80 years and older. Period-specific IHR and IFR estimates were consistently less than 0.3% and 0.1% overall. By age group, IHR and IFR estimates were less than 1.0% and up to 0.1%, respectively, except among adults aged 70-79 years during the sixth to seventh intersurvey period (IHR 3.3% and IFR 1.0%) and among those aged 80 years and older during all periods (IHR 4.7%, 2.2% and 3.5%; IFR 3.3%, 0.6% and 1.3% during the sixth to seventh, seventh to eighth and eighth to ninth periods, respectively). The risk of severe outcome followed a J-shaped age pattern. During the eighth to ninth period, we estimated about 1 hospital admission for COVID-19 per 300 newly infected children younger than 5 years versus about 1 per 30 newly infected adults aged 80 years and older, with no deaths from COVID-19 among children but about 1 death per 80 newly infected adults aged 80 years and older during that period. INTERPRETATION: By July 2023, we estimated about 80% of residents in the Lower Mainland, BC, had been infected with SARS-CoV-2 overall, with low risk of hospital admission or death; about 40% of the oldest adults, however, remained uninfected and at highest risk of a severe outcome. First infections among older adults may still contribute substantial burden from COVID-19, reinforcing the need to continue to prioritize this age group for vaccination and to consider them in health care system planning.

Validation of case definition algorithms for the ascertainment of congenital anomalies.

BACKGROUND: Congenital anomalies (CA) are one of the leading causes of infant mortality and long-term disability. Many jurisdictions rely on health administrative data to monitor these conditions. Case definition algorithms can be used to monitor CA; however, validation of these algorithms is needed to understand the strengths and limitations of the data. This study aimed to validate case definition algorithms used in a CA surveillance system in British Columbia (BC), Canada. METHODS: A cohort of births between March 2000 and April 2002 in BC was linked to the Health Status Registry (HSR) and the BC Congenital Anomalies Surveillance System (BCCASS) to identify cases and non-cases of specific anomalies within each surveillance system. Measures of algorithm performance were calculated for each CA using the HSR as the reference standard. Agreement between both databases was calculated using kappa coefficient. The modified Standards for Reporting Diagnostic Accuracy guidelines were used to enhance the quality of the study. RESULTS: Measures of algorithm performance varied by condition. Positive predictive value (PPV) ranged between approximately 73%-100%. Sensitivity was lower than PPV for most conditions. Internal congenital anomalies or conditions not easily identifiable at birth had the lowest sensitivity. Specificity and negative predictive value exceeded 99% for all algorithms. CONCLUSION: Case definition algorithms may be used to monitor CA at the population level. Accuracy of algorithms is higher for conditions that are easily identified at birth. Jurisdictions with similar administrative data may benefit from using validated case definitions for CA surveillance as this facilitates cross-jurisdictional comparison.

Serial cross-sectional estimation of vaccine-and infection-induced SARS-CoV-2 seroprevalence in British Columbia, Canada.

BACKGROUND: The evolving proportion of the population considered immunologically naive versus primed for more efficient immune memory response to SARS-CoV-2 has implications for risk assessment. We sought to chronicle vaccine- and infection-induced seroprevalence across the first 7 waves of the COVID-19 pandemic in British Columbia, Canada. METHODS: During 8 cross-sectional serosurveys conducted between March 2020 and August 2022, we obtained anonymized residual sera from children and adults who attended an outpatient laboratory network in the Lower Mainland (Greater Vancouver and Fraser Valley). We used at least 3 immunoassays per serosurvey to detect SARS-CoV-2 spike and nucleocapsid antibodies. We assessed any seroprevalence (vaccineor infection-induced, or both), defined by positivity on any 2 assays, and infection-induced seroprevalence, also defined by dual-assay positivity but requiring both antinucleocapsid and antispike detection. We used estimates of infection-induced seroprevalence to explore underascertainment of infections by surveillance case reports. RESULTS: By January 2021, we estimated that any seroprevalence remained less than 5%, increasing with vaccine rollout to 56% by May-June 2021, 83% by September-October 2021 and 95% by March 2022. Infection-induced seroprevalence remained less than 15% through September-October 2021, increasing across Omicron waves to 42% by March 2022 and 61% by July-August 2022. By August 2022, 70%-80% of children younger than 20 years and 60%-70% of adults aged 20-59 years had been infected, but fewer than half of adults aged 60 years and older had been infected. Compared with estimates of infection-induced seroprevalence, surveillance case reports underestimated infections 12-fold between September 2021 and March 2022 and 92-fold between March 2022 and August 2022. INTERPRETATION: By August 2022, most children and adults younger than 60 years had evidence of both SARS-CoV-2 vaccination and infection. As previous evidence suggests that a history of both exposures may induce stronger, more durable hybrid immunity than either exposure alone, older adults - who have the lowest infection rates but highest risk of severe outcomes - continue to warrant prioritized vaccination.

SARS-CoV-2 mRNA Vaccine Effectiveness in Health Care Workers by Dosing Interval and Time Since Vaccination: Test-Negative Design, British Columbia, Canada.

Background: One- and two-dose mRNA vaccine effectiveness (VE) estimates against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection by dosing interval and time since vaccination were assessed among healthcare workers (HCWs) in publicly funded acute and community (nonresidential) healthcare facilities in British Columbia, Canada. Methods: A test-negative design was used with controls matched to cases (6:1) on epidemiological week of SARS-CoV-2 test date. mRNA vaccination was defined by receipt of the first dose ≥21 days or second dose ≥14 days before the test date. HCWs ≥18 years old tested for SARS-CoV-2 between epi-weeks 3 and 39 (January 17-October 2, 2021) were included, when varying dosing intervals and a mix of circulating variants of concern contributed, including Delta dominance provincially from epi-week 31 (August 1). Results: Single- and two-dose analyses included 1265 and 1246 cases, respectively. The median follow-up period (interquartile range) was 49 (34-69) days for single-dose and 89 (61-123) days for two-dose recipients, with 12%, 31%, and 58% of second doses given 3-5, 6, or ≥7 weeks after the first. Adjusted mRNA VE against SARS-CoV-2 was 71% (95% CI, 66%-76%) for one dose and 90% (95% CI, 88%-92%) for two doses, similar to two heterologous mRNA doses (92%; 95% CI, 86%-95%). Two-dose VE remained >80% at ≥28 weeks post-second dose. Two-dose VE was consistently 5%-7% higher with a ≥7-week vs 3-5-week interval between doses, but with overlapping confidence intervals. Conclusions: Among HCWs, we report substantial single-dose and strong and sustained two-dose mRNA vaccine protection, with the latter maintained for at least 7 months. These findings support a longer interval between doses, with global health and equity implications.

Two-Dose Severe Acute Respiratory Syndrome Coronavirus 2 Vaccine Effectiveness With Mixed Schedules and Extended Dosing Intervals: Test-Negative Design Studies From British Columbia and Quebec, Canada.

BACKGROUND: The Canadian coronavirus disease 2019 (COVID-19) immunization strategy deferred second doses and allowed mixed schedules. We compared 2-dose vaccine effectiveness (VE) by vaccine type (mRNA and/or ChAdOx1), interval between doses, and time since second dose in 2 of Canada's larger provinces. METHODS: Two-dose VE against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or hospitalization among adults ≥18 years, including due to Alpha, Gamma, and Delta variants of concern (VOCs), was assessed ≥14 days postvaccination by test-negative design studies separately conducted in British Columbia and Quebec, Canada, between 30 May and 27 November (epi-weeks 22-47) 2021. RESULTS: In both provinces, all homologous or heterologous mRNA and/or ChAdOx1 2-dose schedules were associated with ≥90% reduction in SARS-CoV-2 hospitalization risk for ≥7 months. With slight decline from a peak of >90%, VE against infection was ≥80% for ≥6 months following homologous mRNA vaccination, lower by ∼10% when both doses were ChAdOx1 but comparably high following heterologous ChAdOx1 + mRNA receipt. Findings were similar by age group, sex, and VOC. VE was significantly higher with longer 7-8-week versus manufacturer-specified 3-4-week intervals between mRNA doses. CONCLUSIONS: Two doses of any mRNA and/or ChAdOx1 combination gave substantial and sustained protection against SARS-CoV-2 hospitalization, spanning Delta-dominant circulation. ChAdOx1 VE against infection was improved by heterologous mRNA series completion. A 7-8-week interval between first and second doses improved mRNA VE and may be the optimal schedule outside periods of intense epidemic surge. Findings support interchangeability and extended intervals between SARS-CoV-2 vaccine doses, with potential global implications for low-coverage areas and, going forward, for children.

Priorities among effective clinical preventive services in British Columbia, Canada.

BACKGROUND: Despite the long-standing experience of rating the evidence for clinical preventive services, the delivery of effective clinical preventive services in Canada and elsewhere is less than optimal. We outline an approach used in British Columbia to assist in determining which effective clinical preventive services are worth doing. METHODS: We calculated the clinically preventable burden and cost-effectiveness for 28 clinical preventive services that received a 'strong or conditional (weak) recommendation for' by the Canadian Task Force on Preventive Health Care or an 'A' or 'B' rating by the United States Preventive Services Task Force. Clinically preventable burden is the total quality adjusted life years that could be gained if the clinical preventive services were delivered at recommended intervals to a British Columbia birth cohort of 40,000 individuals over the years of life that the service is recommended. Cost-effectiveness is the net cost per quality adjusted life year gained. RESULTS: Clinical preventive services with the highest population impact and best value for money include services that address tobacco use in adolescents and adults, exclusive breastfeeding, and screening for hypertension and other cardiovascular disease risk factors followed by appropriate pharmaceutical treatment. In addition, alcohol misuse screening and brief counseling, one-time screening for hepatitis C virus infection in British Columbia adults born between 1945 and 1965, and screening for type 2 diabetes approach these high-value clinical preventive services. CONCLUSIONS: These results enable policy makers to say with some confidence what preventive manoeuvres are worth doing but further work is required to determine the best way to deliver these services to all those eligible and to establish what supportive services are required. After all, if a clinical preventive service is worth doing, it is worth doing well.

Implementation of the BC Congenital Anomalies Surveillance System (BCCASS).

SETTING: Congenital anomalies (CAs) can cause lifelong morbidity and accounted for 23.2% of infant deaths from 2003 to 2007. In British Columbia (BC), surveillance of CAs has been irregular since the early 2000s. To enhance CAs surveillance in BC, the Public Health Agency of Canada has provided funding for the implementation of the BC Congenital Anomalies Surveillance System (BCCASS). INTERVENTION: BCCASS is a population-based surveillance system. The system leverages existing administrative data sources that capture information regarding vital events, disease status, drug prescription, and healthcare utilization. The system uses a series of algorithms to capture specific CAs diagnoses, some of which are further validated with the support of the Provincial Advisory Committee. This Advisory Committee is a multi-stakeholder coalition that includes the BC Office of the Provincial Health Officer, subject matter experts, data partners, users, and academia, and acts to provide support, expertise, and strategic guidance to BCCASS. OUTCOMES: Through BCCASS, prevalence and historical trends for 35 CAs in BC are available. Information pertaining to maternal place of residence, risk, and protective factors can be used for association studies such as links to environmental hazards and cluster analysis. IMPLICATIONS: BCCASS is a cost-effective and sustainable system that leverages existing data sources necessary to understand the overall burden of CAs across the BC population. This is fundamental to support data-driven decisions around policy development, program planning, and evaluation of preventive measures. Strong coalitions with stakeholders are instrumental to ensure successful implementation and expansion in the future.

RéSUME: CONTEXTE: Les anomalies congénitales (AC) peuvent causer une morbidité à vie et ont représenté 23,2 % des décès infantiles de 2003 à 2007. En Colombie-Britannique, la surveillance des AC a été irrégulière depuis le début des années 2000. Afin d'améliorer la surveillance de l'AC en Colombie-Britannique, l'Agence de la santé publique du Canada a financé la mise en œuvre du BC Congenital Anomalies Surveillance System (BCCASS). INTERVENTION: Le BCCASS est un système de surveillance basé sur la population. Le système exploite les sources de données administratives existantes qui capturent des informations concernant les événements vitaux, les diagnostics médicaux, la prescription de médicaments et l'utilisation des soins de santé. Le système utilise une série d'algorithmes pour saisir des diagnostics d'AC spécifiques, dont certains sont ensuite validés avec le soutien du Comité consultatif provincial. Ce comité consultatif est une coalition multipartite entre le bureau de l'Agence de santé provincial de la Colombie-Britannique, des experts en la matière, des partenaires de données, des utilisateurs et des universitaires, qui agit pour fournir un soutien, une expertise et des conseils stratégiques au BCCASS. RéSULTATS: Par le BCCASS, la prévalence et les tendances historiques pour 35 AC en Colombie-Britannique sont disponibles. Les informations relatives au lieu de résidence de la mère, aux facteurs de risque et de protection peuvent être utilisées pour des études d'association telles que les liens avec les facteurs environnementaux et l'analyse typologique. INCIDENCES: Le BCCASS est un système rentable et durable qui tire parti des sources de données existantes nécessaires pour comprendre le fardeau global des CA dans l'ensemble de la population de la Colombie-Britannique. Ceci est fondamental pour soutenir les décisions fondées sur les données concernant l'élaboration de politiques, la planification de programmes et l'évaluation des mesures préventives. Des coalitions solides avec les parties prenantes sont essentielles pour assurer une mise en œuvre et une expansion réussie dans l'avenir.

Comparative Single-Dose mRNA and ChAdOx1 Vaccine Effectiveness Against Severe Acute Respiratory Syndrome Coronavirus 2, Including Variants of Concern: Test-Negative Design, British Columbia, Canada.

BACKGROUND: In British Columbia, Canada, most adults 50-69 years old became eligible for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine in April 2021, with chimpanzee adenoviral vectored vaccine (ChAdOx1) restricted to ≥55-year-olds and second doses deferred ≥6 weeks to optimize single-dose coverage. METHODS: Among adults 50-69 years old, single-dose messenger RNA (mRNA) and ChAdOx1 vaccine effectiveness (VE) against SARS-CoV-2 infection and hospitalization, including variant-specific, was assessed by test-negative design between 4 April and 2 October 2021. RESULTS: Single-dose VE included 11 861 cases and 99 544 controls. Median of postvaccination follow-up was 32 days (interquartile range, 15-52 days). Alpha, Gamma, and Delta variants comprised 23%, 18%, and 56%, respectively, of genetically characterized viruses. At 21-55 days postvaccination, single-dose mRNA and ChAdOx1 VE (95% confidence interval [CI]) was 74% (71%-76%) and 59% (53%-65%) against any infection and 86% (80%-90%) and 94% (85%-97%) against hospitalization, respectively. VE (95% CI) was similar against Alpha and Gamma infections for mRNA (80% [76%-84%] and 80% [75%-84%], respectively) and ChAdOx1 (69% [60%-76%] and 66% [56%-73%], respectively). mRNA VE was lower at 63% (95% CI, 56%-69%) against Delta but 85% (95% CI, 71%-92%) against Delta-associated hospitalization (nonestimable for ChAdOx1). CONCLUSIONS: A single mRNA or ChAdOx1 vaccine dose gave important protection against SARS-CoV-2, including early variants of concern. ChAdOx1 VE was lower against infection, but 1 dose of either vaccine reduced the hospitalization risk by >85% to at least 8 weeks postvaccination. Findings inform program options, including longer dosing intervals.

Single-dose mRNA Vaccine Effectiveness Against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), Including Alpha and Gamma Variants: A Test-negative Design in Adults 70 Years and Older in British Columbia, Canada.

BACKGROUND: Randomized-controlled trials of messenger RNA (mRNA) vaccine protection against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) included relatively few elderly participants. We assess single-dose mRNA vaccine effectiveness (VE) in adults ≥ 70 years old in British Columbia, Canada, where second doses were deferred by up to 16 weeks and where a spring 2021 wave uniquely included codominant circulation of Alpha (B.1.1.7) and Gamma (P.1) variants of concern (VOC). METHODS: Analyses included community-dwelling adults ≥ 70 years old with specimen collection between 4 April (epidemiological week 14) and 1 May (week 17) 2021. Adjusted VE was estimated by test-negative design. Cases were reverse-transcription polymerase chain reaction (RT-PCR) test-positive for SARS-CoV-2, and controls were test-negative. Vaccine status was defined by receipt of a single-dose ≥ 21 days before specimen collection, but a range of intervals was assessed. Variant-specific VE was estimated against viruses genetically characterized as Alpha, Gamma or non-VOC lineages. RESULTS: VE analyses included 16 993 specimens: 1226 (7%) test-positive cases and 15 767 test-negative controls. Of 1131 (92%) genetically characterized viruses, 509 (45%), 314 (28%), and 276 (24%) were Alpha, Gamma, and non-VOC lineages, respectively. At 0-13 days postvaccination, VE was negligible at 14% (95% confidence interval [CI], 0-26) but increased from 43% (95% CI, 30-53) at 14-20 days to 75% (95% CI, 63-83) at 35-41 days postvaccination. VE at ≥ 21 days postvaccination was 65% (95% CI, 58-71) overall: 72% (95% CI, 58-81), 67% (95% CI, 57-75), and 61% (95% CI, 45-72) for non-VOC, Alpha, and Gamma variants, respectively. CONCLUSIONS: A single dose of mRNA vaccine reduced the risk of SARS-CoV-2 by about two-thirds in adults ≥ 70 years old, with protection only minimally reduced against Alpha and Gamma variants.

Rapid Increase in SARS-CoV-2 P.1 Lineage Leading to Codominance with B.1.1.7 Lineage, British Columbia, Canada, January-April 2021.

Several severe acute respiratory syndrome coronavirus 2 variants of concern (VOCs) emerged in late 2020; lineage B.1.1.7 initially dominated globally. However, lineages B.1.351 and P.1 represent potentially greater risk for transmission and immune escape. In British Columbia, Canada, B.1.1.7 and B.1.351 were first identified in December 2020 and P.1 in February 2021. We combined quantitative PCR and whole-genome sequencing to assess relative contribution of VOCs in nearly 67,000 infections during the first 16 weeks of 2021 in British Columbia. B.1.1.7 accounted for <10% of screened or sequenced specimens early on, increasing to >50% by week 8. P.1 accounted for <10% until week 10, increased rapidly to peak at week 12, and by week 13 codominated within 10% of rates of B.1.1.7. B.1.351 was a minority throughout. This rapid expansion of P.1 but suppression of B.1.351 expands our understanding of population-level VOC patterns and might provide clues to fitness determinants for emerging VOCs.

Passive Tick Surveillance and Detection of Borrelia Species in Ticks from British Columbia, Canada: 2002-2018.

Lyme disease, caused by Borrelia burgdorferi sensu lato (s.l.) complex, is the most common vector-borne disease in North America. This disease has a much lower incidence in western compared with eastern North America. Passive tick surveillance data submitted over 17 years from 2002 to 2018 were analyzed to determine the occurrence of tick species and the prevalence of Borrelia spp. in ticks in British Columbia (BC), Canada. The BC Centre for Disease Control Public Health Laboratory received tick submissions from physicians, veterinarians, and BC residents. Ticks were identified to species, and all ticks, except Dermacentor andersoni, were tested using generic B. burgdorferi s.l. primer sets and species-specific PCR primer sets for B. burgdorferi sensu stricto (s.s.). Tick submission data were analyzed to assess temporal and geographical trends, tick life stages, and tick species. Poisson regression was used to assess temporal trends in annual tick submissions. A total of 15,464 ticks were submitted. Among these, 0.29% (n = 10,235) of Ixodes spp. ticks and 5.3% (n = 434) of Rhipicephalus sanguineus ticks were found carrying B. burgdorferi s.s. B. burgdorferi s.s. was primarily detected in Ixodes pacificus (52%; n = 16) and Ixodes angustus ticks (19%; n = 6) retrieved from humans (n = 5) and animals (n = 26). B. burgdorferi was found in ticks submitted throughout the year. Ixodes spp. ticks were primarily submitted from the coastal regions of southwestern BC, and D. andersoni ticks were primarily submitted from southern interior BC. The number of human tick submissions increased significantly (p < 0.001) between 2013 and 2018. The annual prevalence of B. burgdorferi in ticks remained stable during the study period. These findings correspond to those observed in US Pacific Northwestern states. Passive tick surveillance is an efficient tool to monitor long-term trends in tick distribution and B. burgdorferi prevalence in a low endemicity region.

The Impact of Treatment as Prevention on the HIV Epidemic in British Columbia, Canada.

PURPOSE OF REVIEW: This study proposes to describe the impact of a publicly funded Treatment as Prevention (TasP) strategy in British Columbia (BC), Canada, in decreasing the individual and public health impact of the HIV/AIDS Epidemic. RECENT FINDINGS: In BC, TasP has been associated with a steady decline in HIV-related morbidity and mortality. At the same time, a demographic transition was observed among people living with HIV (PLWH), with the majority of those on antiretroviral treatment (ART) now ≥ 50 years of age, living with at least one comorbidity, and dying from age-associated comorbidities. We also documented a progressive increase in the proportion of viral load suppression as a result of ART expansion. While the pre-ART CD4 T cell count has increased steadily in recent years, there is still a large proportion of PLWH being diagnosed in later stages of HIV infection. New HIV diagnoses have been rapidly declining, however to a lesser extent among men who have sex with men (MSM), and BC is currently experiencing an increase in infectious syphilis cases in this population. These facts reinforce the effectiveness of TasP in decreasing HIV transmission, but at the same time, it highlights the need for further innovation to enhance the control of HIV and syphilis among MSM. This study supports the development of new approaches that address existing gaps in the TasP strategy in BC, and the future health needs of PLWH.

Narrowing the policy gap: lessons from years 2 and 3 of the British Columbia influenza prevention policy.

Influenza can be potentially fatal to vulnerable populations, particularly those in the hospital. Canada's National Advisory Committee on Immunization recommends that health-care workers (HCW) be immunized against influenza partly to avoid infecting high-risk populations. However, influenza immunization rates among HCW remain suboptimal. In 2012, health authorities across British Columbia (B.C.) implemented a province-wide influenza prevention policy requiring HCW to either be immunized or wear a mask when in patient-care areas during the influenza season. This paper describes the second of two studies focused on what was learned from years 2 and 3 of the policy. A case study approach was used to examine this policy implementation event. Qualitative data were collected through key documents and key informant interviews with members of leadership teams responsible for policy implementation. Framework analysis and Prior's approach were used to analyze data from interviews and documents, respectively. Policy implementation varied by geographic region and gaps persist in immunization tracking and discipline for noncompliance. Debate regarding the scientific evidence used to support the policy fuels resistance from particular groups. Despite these challenges, findings suggest that the policy has been habituated, largely due to consistent policy objectives. This study emphasizes the importance of ongoing inter-professional and cross-sectoral program evaluation. While adherence may be routine for many, implementation processes must continue to respond to contextual issues to narrow the gap in policy implementation and to continue to engage stakeholders to ensure compliance.

Are we prepared? The development of performance indicators for public health emergency preparedness using a modified Delphi approach.

BACKGROUND: Disasters and emergencies from infectious diseases, extreme weather and anthropogenic events are increasingly common. While risks vary for different communities, disaster and emergency preparedness is recognized as essential for all nation-states. Evidence to inform measurement of preparedness is lacking. The objective of this study was to identify and define a set of public health emergency preparedness (PHEP) indicators to advance performance measurement for local/regional public health agencies. METHODS: A three-round modified Delphi technique was employed to develop indicators for PHEP. The study was conducted in Canada with a national panel of 33 experts and completed in 2018. A list of indicators was derived from the literature. Indicators were rated by importance and actionability until achieving consensus. RESULTS: The scoping review resulted in 62 indicators being included for rating by the panel. Panel feedback provided refinements to indicators and suggestions for new indicators. In total, 76 indicators were proposed for rating across all three rounds; of these, 67 were considered to be important and actionable PHEP indicators. CONCLUSIONS: This study developed an indicator set of 67 PHEP indicators, aligned with a PHEP framework for resilience. The 67 indicators represent important and actionable dimensions of PHEP practice in Canada that can be used by local/regional public health agencies and validated in other jurisdictions to assess readiness and measure improvement in their critical role of protecting community health.

Drug checking services at music festivals and events in a Canadian setting.

OBJECTIVES: Drug checking is a harm reduction intervention that allows for identification of drug composition. The objective of the study was to assess drug market components and concordance between expected substance reported by clients and results from point-of-care drug checking at music festivals and events in British Columbia. METHODS: From July to September 2018, we provided drug checking services at four events using combination Fourier Transform Infrared (FTIR) spectroscopy and fentanyl immunoassay strips. We measured concordance between expected substance as reported by clients to the results from the FTIR/fentanyl immunoassay strip and tracked unexpected adulterants. RESULTS: In total, 336 checks were completed. Most samples were expected by clients to be psychedelics (69.3%) or stimulants (19.6%). Of the 233 psychedelic samples, 169 (72.5%) contained the expected, unadulterated substance, and 27 (11.6%) contained additional contaminants. Of 66 stimulant samples, 41 (62.1%) contained expected substance, while 24 (36.4%) contained additional contaminants. Unexpected adulterants such as fentanyl, levamisole, and phenacetin were also found, in addition to several novel psychoactive substances. DISCUSSION: We found a large proportion of substances that contained unexpected adulterants. Our findings highlight the value of continued drug checking and will be helpful in designing future harm reduction interventions in similar contexts.

Measuring the impact of influenza vaccination on healthcare worker absenteeism in the context of a province-wide mandatory vaccinate-or-mask policy.

OBJECTIVES: In 2012, British Columbia (BC) implemented a province-wide vaccinate-or-mask influenza prevention policy for healthcare workers (HCWs) with the aim of improving HCW coverage, and reducing illness in patients and staff. We assess post-policy impacts of HCW vaccination status on their absenteeism. METHODS: We matched individual HCW payroll data from December 1, 2012 to March 31, 2017 with annually self-reported vaccination status for BC health authority employees to assess sick rates (sick time as a proportion of sick time and productive time). We modelled adjusted odds ratios (OR) of taking any sick time, relative rates (RR) of sick time taken, and predicted mean sick rates by vaccination status in influenza (December 1-March 31) and non-influenza seasons (April 1 to November 30). We used two methods to assess changes in influenza season sick rates for HCWs who had a change in their vaccination status over the five years. RESULTS: HCWs who reported 'early' vaccination (before December 1 when the policy is in effect) were less likely to take sick time (OR 0.874, 95%CI: 0.866-0.881) and took less sick time (RR 0.907, 95%CI: 0.901-0.912) in influenza season compared to HCWs who did not report vaccination; whereas HCWs who reported 'late' (between December 1 and March 31, and subject to masking until vaccinated) had similar sick rates to HCWs who did not report vaccination. These trends were also observed in non-influenza season. Influenza season sick rates were similar for HCWs that had at least one year of 'early' vaccination and one year where vaccination was not reported over the five year period. CONCLUSIONS: Overall absenteeism is lower among HCWs who report vaccination versus those who do not report. However, absenteeism behaviours appear to be influenced by individual level factors other than vaccination status.

Measuring the impact of a mandatory province-wide vaccinate-or-mask policy on healthcare worker absenteeism in British Columbia, Canada.

OBJECTIVES: Vaccinate-or-mask (VOM) policies aim to improve influenza vaccine coverage among healthcare workers (HCW) and reduce influenza-related illness among patients and staff. In 2012, British Columbia (BC) implemented a province-wide VOM influenza prevention policy. This study describes an evaluation of policy impacts on HCW absenteeism rates from before to after policy implementation. METHODS: Using payroll data from regional and provincial Health Authorities (HA), we assessed all-cause sick rates (sick time as a proportion of sick time and productive time) before (2007-2011, excluding 2009-2010) and after (2012-2017) policy implementation, and during influenza season (December 1-March 31) and non-influenza season (April 1-November 30). We used a two-part negative binomial hurdle model to calculate odds ratios (OR) of taking any sick time, relative rates (RR) of sick time taken, and predicted mean sick rates, adjusting for age group, sex, job type, job classification, HA, year and vaccine effectiveness. RESULTS: During influenza season, HCWs in the post-policy period were less likely to take any sick time (OR 0.989, 95%CI: 0.979-0.999) but had higher rates of sick time (RR 1.038, 95%CI: 1.030-1.045). However, during non-influenza season, HCWs in the post-policy period were more likely to take any sick time (OR 1.015, 95%CI: 1.008-1.022) but had lower rates of sick time (RR 0.971, 95%CI: 0.966-0.976). There was an overall increase in predicted mean sick rate from pre to post-policy in influenza season (4.392% to 4.508%) and non-influenza season (3.815% to 3.901%). CONCLUSIONS: The observed year-round increase in sick rates from pre-to-post policy was likely influenced by other factors; however, opposite trends in how HCWs took sick time in the influenza and non-influenza seasons may reflect policy influences and need further research to explore reasons for these differences.

Modelling the combined impact of interventions in averting deaths during a synthetic-opioid overdose epidemic.

BACKGROUND AND AIMS: The province of British Columbia (BC) Canada has experienced a rapid increase in illicit drug overdoses and deaths during the last 4 years, with a provincial emergency declared in April 2016. These deaths have been driven primarily by the introduction of synthetic opioids into the illicit opioid supply. This study aimed to measure the combined impact of large-scale opioid overdose interventions implemented in BC between April 2016 and December 2017 on the number of deaths averted. DESIGN: We expanded on the mathematical modelling methodology of our previous study to construct a Bayesian hierarchical latent Markov process model to estimate monthly overdose and overdose-death risk, along with the impact of interventions. SETTING AND CASES: Overdose events and overdose-related deaths in BC from January 2012 to December 2017. INTERVENTIONS: The interventions considered were take-home naloxone kits, overdose prevention/supervised consumption sites and opioid agonist therapy MEASUREMENTS: Counterfactual simulations were performed with the fitted model to estimate the number of death events averted for each intervention and in combination. FINDINGS: Between April 2016 and December 2017, BC observed 2177 overdose deaths (77% fentanyl-detected). During the same period, an estimated 3030 (2900-3240) death events were averted by all interventions combined. In isolation, 1580 (1480-1740) were averted by take-home naloxone, 230 (160-350) by overdose prevention services and 590 (510-720) were averted by opioid agonist therapy. CONCLUSIONS: A combined intervention approach has been effective in averting overdose deaths during British Columbia's opioid overdose crisis in the period since declaration of a public health emergency (April 2016-December 2017). However, the absolute numbers of overdose deaths have not changed.

Missed opportunities for earlier diagnosis of HIV in British Columbia, Canada: A retrospective cohort study.

BACKGROUND: Late HIV diagnosis is associated with increased AIDS-related morbidity and mortality as well as an increased risk of HIV transmission. In this study, we quantified and characterized missed opportunities for earlier HIV diagnosis in British Columbia (BC), Canada. DESIGN: Retrospective cohort. METHODS: A missed opportunity was defined as a healthcare encounter due to a clinical manifestation which may be caused by HIV infection, or is frequently present among those with HIV infection, but no HIV diagnosis followed within 30 days. We developed an algorithm to identify missed opportunities within one, three, and five years prior to diagnosis. The algorithm was applied to the BC STOP HIV/AIDS population-based cohort. Eligible individuals were ≥18 years old, and diagnosed from 2001-2014. Multivariable logistic regression identified factors associated with missed opportunities. RESULTS: Of 2119 individuals, 7%, 12% and 14% had ≥1 missed opportunity during one, three and five years prior to HIV diagnosis, respectively. In all analyses, individuals aged ≥40 years, heterosexuals or people who ever injected drugs, and those residing in Northern health authority had increased odds of experiencing ≥1 missed opportunity. In the three and five-year analysis, individuals with a CD4 count <350 cells/mm3 were at higher odds of experiencing ≥1 missed opportunity. Prominent missed opportunities were related to recurrent pneumonia, herpes zoster/shingles among younger individuals, and anemia related to nutritional deficiencies or unspecified cause. CONCLUSIONS: Based on our newly-developed algorithm, this study demonstrated that HIV-diagnosed individuals in BC have experienced several missed opportunities for earlier diagnosis. Specific clinical indicator conditions and population sub-groups at increased risk of experiencing these missed opportunities were identified. Further work is required in order to validate the utility of this proposed algorithm by establishing the sensitivity, specificity, positive and negative predictive values corresponding to the incidence of the clinical indicator conditions among both HIV-diagnosed and HIV-negative populations.