In May 2023, the US Food and Drug Administration (FDA) initially approved an AS01_E-adjuvanted respiratory syncytial virus (RSV) prefusion F protein-based vaccine (adjuvanted RSVPreF3) for adults aged ≥60 years. The approval was expanded in June 2024 to include adults 50–59 years of age at increased risk for RSV-associated lower respiratory tract disease. In this paper, we describe the protocol of a postmarketing safety study evaluating the association between adjuvanted RSVPreF3 and new-onset Guillain-Barré syndrome (GBS), acute disseminated encephalomyelitis (ADEM) and atrial fibrillation (AF) among adults ≥50 years of age in the USA and provide our rationale for key methodological decisions.

The potential associations between adjuvanted RSVPreF3 and GBS, ADEM and AF will be evaluated using secondary healthcare data and the self-controlled risk interval (SCRI) design. Data from five research partners in the USA spanning August 2023 through June 2030 will be used for the conduct of yearly monitoring queries and, sample size permitting, SCRI analyses. Claims-based definitions for new-onset outcomes (first diagnosis in 365 days) are: ≥1 inpatient diagnosis for GBS and ADEM; ≥1 inpatient or ≥2 ambulatory/emergency diagnoses for AF. The primary risk and control windows are 1–42 and 43–84 days, respectively, for GBS and ADEM; and 1–8 and 9–16 days for AF. SCRI analyses for GBS and ADEM will include chart-confirmed cases. SCRI analyses for AF will adjust for the positive predictive value obtained from validation against charts. Conditional Poisson regression will be used to calculate incidence rate ratios.

This study was approved by the Institutional Review Boards (IRB) of Harvard Pilgrim Health Care Institute; WIRB-Copernicus Group, Inc and its affiliates (collectively, ‘WCG’); WCG IRB, Inc; and Sterling IRB, with Federal Wide Assurance (FWA) numbers FWA00000100, FWA00033319 and FWA00025632, respectively, for all participating research partners. Study results will be shared with the US FDA and publicly disseminated through national or international clinical or scientific conferences and peer-reviewed publications.

This protocol has been registered in the Heads of Medicines Agencies–European Medicines Agency Real World Data Catalogues (EUPAS1000000486).

To assess health service use between days 43 and 365 postdelivery, comparing individuals with and without severe maternal morbidity (SMM).

Population-based cohort study.

Linked datasets from Population Data BC in British Columbia, Canada, April 2013–March 2021.

Postpartum individuals aged >18 years with a hospital or home delivery, with/without SMM occurring from 20 weeks’ gestation through 42 days post partum. Ectopic pregnancies, missing identifiers and maternal deaths at delivery or within 42 days post partum were excluded.

The primary outcome was high health service use, defined as being in the 95th percentile for use of one or more of the following non-obstetric visits: emergency department, hospitalisations and outpatient visits to a primary care physician or specialist—each occurring between 43 and 365 days after delivery hospitalisation discharge. Secondary outcomes included being in the 95th percentile for each visit type. Log binomial regression assessed the rate and risk of high health service use in SMM compared with non-SMM pregnancies, adjusting for confounders.

The cohort included 261 287 deliveries (5575 (2.1%) with SMM). Those with >15 visits within 43–365 days postdelivery were classified as having high health service use. SMM-affected individuals were twice as likely to have high health service use (9.2% vs 4.3%; adjusted relative risk (aRR)=1.96, 95% CI 1.78 to 2.17). Individuals with non-hypertensive cardiovascular SMM had markedly higher health service use (21.4% vs 4.3%; aRR=5.18, 95% CI 3.28 to 8.16). There was heterogeneity in the association between SMM and high health service use among those without versus with previous comorbidities, without versus with high service use in the 2 years prior to delivery, and without vs with preterm birth.

Our study revealed high health service use after SMM. These findings can help guide the development of standardised postpartum care pathways.

To investigate vaccination coverage for influenza and COVID-19 in the SARS-CoV-2 immunity and reinfection evaluation (SIREN) study cohort of healthcare workers (HCWs) between 2020 and 2023 and explore vaccination enablers and barriers.

A mixed-methods study nested within SIREN, a multicentre prospective cohort study of HCWs across the UK. Quantitative and qualitative methods were used sequentially, using an expansion/explanation function, enabling emergent themes observed from the quantitative stage to be explored in the qualitative stage.

SIREN sites include secondary care centres and community mental health trusts in the UK.

Quantitative analysis was conducted on data from 6048 participants. Participants were representative of the HCW workforce, with the majority being women (83%) and of white ethnicity (88%). Nurses made up the largest occupational group (33%). Qualitative analysis of data from 24 participants including five focus groups (n=21) and three semistructured interviews (n=3); 82% women, 26% minority ethnic, all working age from across the UK.

Quantitative: vaccine coverage for COVID-19 and influenza vaccines by demographic with multivariable logistical regression used to assess differences. Qualitative: thematic analysis to explore reasons behind the results seen in the quantitative stage.

COVID-19 vaccination was initially high; 97% received two doses and 94% a first booster. However, coverage was reduced to 77%, for the second booster. Influenza vaccination coverage was lowest in 2020–2021 (46%), increasing to 73% in 2021–2022 and to 79% in 2022–2023. In 2022–2023, vaccination coverage was higher for influenza than for COVID-19. High vaccine coverage for both COVID-19 and influenza was observed in doctors, pharmacists and therapists. Porters, healthcare assistants and staff from minority ethnic groups had lower vaccine coverage for both COVID-19 and influenza. Four themes were identified: (1) attitudes towards vaccination changed throughout the COVID-19 pandemic; (2) HCWs used data to inform vaccination decisions; (3) poor communication in healthcare settings contributed to a reduction in vaccination; (4) there were both positive and negative impacts of the COVID-19 vaccine on influenza vaccine uptake and other vaccination programmes.

Between 2020 and 2023 in our cohort, COVID-19 vaccination coverage decreased, whereas influenza increased. Our study found attitudes to both vaccines have shifted, becoming more favourable to influenza and less to COVID-19 boosters. Barriers to COVID-19 boosters, including concerns about side effects and vaccine effectiveness, need to be addressed with improved communication on the benefits and adverse events. Future vaccination strategies should address the differences we have identified in vaccine coverage across demographics and occupational groups, including continued efforts to improve vaccine equity.

ISRCTN11041050.

To understand experiences of stigma and discrimination among adults who are homeless across multiple care and support system contexts.

Cross-sectional survey embedded within an ethnographic case study.

South London, UK, 2024.

Convenience sample of 74 people experiencing homelessness, aged over 18 years.

Participants most commonly reported unfair treatment in public settings (85%), legal settings (72%), housing and homelessness services (68%) and health settings (65%). These experiences were attributed to a range of factors and identities, with homelessness the most commonly cited; people commonly linked unfair experiences to multiple identities. People with more comorbidities reported experiencing unfair treatment across more system settings, including and beyond health systems.

Unfair treatment was reported across multiple care and support systems with greater ill-health associated with more unfair treatment. Future larger-scale surveys should measure the extent of stigma and discrimination across the population.

The introduction of fentanyl and its analogues in the illicit drug supply has prompted greater emphasis on refining clinical treatment protocols to ensure sustained retention in opioid agonist treatment (OAT). Take-home dosing may lessen the treatment burden on clients and thus reduce the risk of treatment discontinuation. The evidence base supporting the use of take-home dosing, including the optimal duration of dispensations, is, however, limited. The objective of this study is to determine the comparative effectiveness of alternative take-home dosing schedules, as observed in clinical practice in British Columbia, Canada from 2010 to 2022.

We propose to emulate a target trial with a population-level retrospective study of individuals initiating methadone or buprenorphine/naloxone between 1 January 2010 and 31 December 2022 who are 18 years of age or older and not currently incarcerated or pregnant with no history of cancer or palliative care. Our study will draw on nine linked health administrative databases from British Columbia and will evaluate take-home doses of 2–5 days, 6 days or >6 days compared with continuous daily dosing. The primary outcomes include OAT discontinuation and all-cause mortality on treatment. A causal per-protocol analysis is proposed with longitudinal matching and inverse probability of censoring weighting approaches to adjust for time-fixed and time-varying confounding. A range of sensitivity analyses will be executed to determine the robustness of results.

The protocol, cohort creation and analysis plan have been classified and approved as a quality improvement initiative by Providence Health Care Research Ethics Board and the Simon Fraser University Office of Research Ethics. Results will be disseminated and shared with local advocacy groups and decision-makers, developers of national and international clinical guidelines, presented at national and international conferences and published in peer-reviewed journals electronically and in print.

Selecting an optimal initial dosage of opioid agonist treatment (OAT) balances effectiveness and safety, as initial doses that are too low may be insufficient, potentially prompting clients to seek unregulated drugs to alleviate withdrawal symptoms, which may increase the likelihood of treatment discontinuation. Conversely, initial doses that are too high carry a risk of overdose. As opioid tolerance levels have risen in the fentanyl era, linked population-level data capturing initial doses in the real world provide a valuable opportunity to refine existing guidance on optimal OAT dosing at treatment initiation. Our objective is to determine the comparative effectiveness of alternative initial doses of methadone, buprenorphine-naloxone and slow-release oral morphine at OAT initiation, as observed in clinical practice in British Columbia (BC), Canada.

We propose a population-level retrospective observational study with a linkage of nine provincial health administrative databases in BC, Canada (1 January 2010 to 31 December 2022). Our study includes two time-to-event primary outcomes: OAT discontinuation and all-cause mortality during follow-up. We propose ‘initiator’ target trial analyses for each medication using both propensity score weighting and instrumental variable analyses to compare the effect of different initial OAT doses on the hazard of time-to-OAT discontinuation and all-cause mortality. A range of sensitivity analyses will be used to assess the robustness of the results.

The protocol, cohort creation and analysis plan have been classified and approved as a quality improvement initiative by Providence Health Care Research Ethics Board and the Simon Fraser University Office of Research Ethics. Results will be disseminated to local advocacy groups and decision-makers, national and international clinical guideline developers, presented at international conferences and published in peer-reviewed journals electronically and in print.

Methadone and buprenorphine/naloxone are effective medications for people with opioid use disorder; however, interruptions in daily dosing are common and diminish the benefits of these medications. While clinical guidelines in most North American jurisdictions, including British Columbia (BC), recommend dose adjustment after treatment interruptions to varying levels of specificity, the evidence to support these recommendations is limited. We aim to estimate the comparative effectiveness of alternative dose adjustment strategies on subsequent overdose-related acute care visits and discontinuation of opioid agonist treatment in BC, Canada.

Using a linkage of nine health administrative databases, we propose a population-level retrospective cohort study of adults aged 18 years or older in BC who initiated methadone or buprenorphine/naloxone between 1 January 2010 and 31 December 2022. We will specify parallel hypothetical trials, known as target trials, for methadone interruptions of 1–3 days, 4 days and 5–14 days, and buprenorphine/naloxone interruptions of 1–5 days and 6–14 days. Following the index interruption, the primary outcomes are the time to overdose-related acute care visits and treatment discontinuation (interruptions lasting >14 days), with time to all-cause acute care visits as a secondary outcome. The intention-to-treat effect will be estimated using both propensity score and instrumental variable approaches. A range of sensitivity analyses will assess the robustness of our results, including cohort and timeline restriction, alternative definitions of exposure and outcome and alternative estimation strategies.

The protocol, cohort creation and analysis plan have been classified and approved as a quality improvement initiative by Providence Health Care Research Institute and the Simon Fraser University Office of Research Ethics. All data are deidentified, securely stored and accessed in accordance with provincial privacy regulations. Results will be disseminated to local advocacy groups and decision-makers, national and international clinical guideline developers, presented at international conferences and published in peer-reviewed journals electronically and in print.