Feasibility of interventions to increase HPV vaccination acceptability and coverage in school-based programs: Findings from a pilot study in Quebec, Canada.

Introduction: Human papillomavirus (HPV) vaccines have been offered in Quebec schools to 4th-grade (9-10 years old) girls since 2008 and boys since 2016. HPV vaccine coverage does not reach the 90 % target in many regions. This project evaluated the feasibility and the acceptability of interventions to improve HPV vaccine acceptability and coverage in school-based programs.

Population-level impact of switching to 1-dose human papillomavirus vaccination in high-income countries: examining uncertainties using mathematical modeling.

Background: A concern in high-income countries is that switching to 1-dose human papillomavirus (HPV) vaccination could cause a rebound in HPV infection and cervical cancer if 1-dose efficacy or duration were inferior to 2 doses. Using mathematical modeling and up-to-date trial-based data, we projected the population-level effectiveness of switching from 2-dose to 1-dose vaccination under different vaccine efficacy and duration assumptions in high-income countries.

Methods: We used HPV-ADVISE (Agent-based Dynamic model for VaccInation and Screening Evaluation), a transmission-dynamic model of HPV infection and cervical cancer, varying key model assumptions to identify those with the greatest impact on projections of HPV-16 and cervical cancer incidence over time: 1) 1-dose vaccine efficacy and vaccine duration, 2) mechanisms of vaccine efficacy and duration over time, 3) midadult (>30 years of age) sexual behavior, 4) progression to cervical cancer among midadults, and 5) vaccination coverage and programs.

Switching from a 2-dose to a 1-dose program of gender-neutral routine vaccination against human papillomavirus in Canada: a mathematical modelling analysis.

Background: Worldwide, countries are examining whether to implement 1-dose human papillomavirus (HPV) vaccination instead of using 2 doses. To inform policy, we sought to project the population-level impact and efficiency of switching from 2-dose to 1-dose gender-neutral routine HPV vaccination in Canada.

Methods: We used HPV-ADVISE, an individual-based transmission-dynamic model of HPV infections and diseases, to mathematically model vaccination programs in 2 provinces, Quebec, a province with high HPV vaccination coverage (around 85%), and Ontario, which has lower coverage (around 65%).

Prevalence of Oral Human Papillomavirus Infection Among Urban Gay, Bisexual, and Other Men Who Have Sex With Men in Canada, 2017-2019.

Background: Oral human papillomavirus (HPV) infections are a leading cause of oropharyngeal cancers. In 2015 and 2016, HPV vaccines became publicly funded for gay, bisexual, and other men who have sex with men (GBM) under 27 years of age in most Canadian provinces.

Methods: Between 2017 and 2019, sexually active GBM in Montreal, Toronto, and Vancouver were recruited through respondent-driven sampling.

Development of Promising Interventions to Improve Human Papillomavirus Vaccination in a School-Based Program in Quebec, Canada: Results From a Formative Evaluation Using a Mixed Methods Design.

Background: Despite the availability of school-based human papillomavirus (HPV) vaccination programs, disparities in vaccine coverage persist. Barriers to HPV vaccine acceptance and uptake include parental attitudes, knowledge, beliefs, and system-level barriers. A total of 3 interventions were developed to address these barriers: an in-person presentation by school nurses, an email reminder with a web-based information and decision aid tool, and a telephone reminder using motivational interviewing (MI) techniques.

Impact of interventions to improve HPV vaccination acceptance and uptake in school-based programs: Findings of a pilot project in Quebec.

Context: Vaccination coverage against human papillomavirus (HPV) in school-based programs in Quebec, Canada, is suboptimal despite more than a decade of introduction. Three interventions to improve HPV vaccine acceptability and coverage in school-based programs were developed, implemented as part of a multicomponent strategy and evaluated.

Method: Sixty-four (64) schools were recruited, of which 32 received the interventions (pilot schools), and 32 received usual vaccination activities (control schools).

School-based vaccination program against HPV and Hepatitis B: A longitudinal analysis of vaccine coverage between 2015 and 2021 in Quebec.

Background: HPV vaccination prevents cancers, including 90% of cervical cancer. Since 2008, a school-based HPV vaccination program has been implemented in Quebec, but vaccine coverage is suboptimal. The COVID-19 pandemic disrupted school-based vaccination programs.

Effectiveness of BNT162b2 Vaccine Against Omicron-SARS-CoV-2 Subvariants in Children 5-11 Years of Age in Quebec, Canada, January 2022 to January 2023.

Background: In premarketing clinical trials conducted before Omicron emergence, BNT162b2 vaccine efficacy against COVID-19 was 90% in children. We conducted postmarketing evaluation of 1- and 2-dose vaccine effectiveness (VE) against Omicron BA.1, BA.

"The problem is not lack of information": A qualitative study of parents and school nurses' perceptions of barriers and potential solutions for HPV vaccination in schools.

Background: HPV vaccination has been offered in school programs for over a decade in Quebec, Canada, but the vaccine coverages are not reaching the target coverage in several regions. This qualitative study aimed to describe barriers and enabling conditions of HPV vaccination as perceived by parents and school nurses and identify potential solutions to improve HPV vaccine uptake rates and acceptance in school-based programs.

Methods: Three focus group discussions were conducted with parents of children in Grades 2 or 3 who were unsure or unwilling to vaccinate.

Effectiveness of previous infection-induced and vaccine-induced protection against hospitalisation due to omicron BA subvariants in older adults: a test-negative, case-control study in Quebec, Canada.

Background: Older adults (aged ≥60 years) were prioritised for COVID-19 booster vaccination due to severe outcome risk, but the risk for this group is also affected by previous SARS-CoV-2 infection and vaccination. We estimated vaccine effectiveness against omicron-associated hospitalisation in older adults by previously documented infection, time since last immunological event, and age group.

Methods: This was a population-based test-negative case-control study done in Quebec, Canada, during BA.

Self-reported Human Papillomavirus Vaccination and Vaccine Effectiveness Among Men Who Have Sex with Men: A Quantitative Bias Analysis.

Background: Self-report of human papillomavirus (HPV) vaccination has ~80-90% sensitivity and ~75-85% specificity. We measured the effect of nondifferential exposure misclassification associated with self-reported vaccination on vaccine effectiveness (VE) estimates.

Methods: Between 2017-2019, we recruited sexually active gay, bisexual, and other men who have sex with men aged 16-30 years in Canada.

Vaccine Effectiveness Against 12-Month Incident and Persistent Anal Human Papillomavirus Infection Among Gay, Bisexual, and Other Men Who Have Sex With Men.

Background: Real-world evidence of human papillomavirus (HPV) vaccine effectiveness (VE) against longitudinal outcomes is lacking among gay, bisexual, and other men who have sex with men (GBM). We compared 12-month incidence and persistence of anal HPV infection between vaccinated and unvaccinated GBM.

Methods: We recruited GBM aged 16-30 years in Montreal, Toronto, and Vancouver, Canada, from 2017 to 2019.

BNT162b2 Effectiveness Against Delta and Omicron Variants of Severe Acute Respiratory Syndrome Coronavirus 2 in Adolescents Aged 12-17 Years, by Dosing Interval and Duration.

Background: Two- and 3-dose BNT162b2 vaccine effectiveness (VE) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, including Delta and Omicron variants, was assessed among adolescents in Canada, where first and second doses were spaced longer than the manufacturer-specified 3-week interval.

Methods: Test-negative design estimated VE against laboratory-confirmed SARS-CoV-2 infection ≥14 days after vaccination among 12-17-year-olds in Quebec and British Columbia, Canada, between 5 September 2021 and 30 April 2022 (epidemiological weeks 36-17). VE was explored by the interval between first and second doses, time since the second dose, and with a third dose.

Estimated Protection of Prior SARS-CoV-2 Infection Against Reinfection With the Omicron Variant Among Messenger RNA-Vaccinated and Nonvaccinated Individuals in Quebec, Canada.

Importance: The Omicron variant is phylogenetically and antigenically distinct from earlier SARS-CoV-2 variants and the original vaccine strain. Protection conferred by prior SARS-CoV-2 infection against Omicron reinfection, with and without vaccination, requires quantification.

Objective: To estimate the protection against Omicron reinfection and hospitalization conferred by prior heterologous non-Omicron SARS-CoV-2 infection and/or up to 3 doses of an ancestral, Wuhan-like messenger RNA (mRNA) vaccine.

Time trends in social contacts of individuals according to comorbidity and vaccination status, before and during the COVID-19 pandemic.

Background: As we are confronted with more transmissible/severe variants with immune escape and the waning of vaccine efficacy, it is particularly relevant to understand how the social contacts of individuals at greater risk of COVID-19 complications evolved over time. We described time trends in social contacts of individuals according to comorbidity and vaccination status before and during the first three waves of the COVID-19 pandemic in Quebec, Canada.

Methods: We used data from CONNECT, a repeated cross-sectional population-based survey of social contacts conducted before (2018/2019) and during the pandemic (April 2020 to July 2021).

Increases in human papillomavirus vaccine coverage over 12 months among a community-recruited cohort of gay, bisexual, and other men who have sex with men in Canada.

Background: Starting in 2015/16, most Canadian provinces introduced publicly-funded human papillomavirus (HPV) vaccination programs for gay, bisexual, and other men who have sex with men (GBM) aged ≤ 26 years. We estimated 12-month changes in HPV vaccine coverage among community-recruited GBM from 2017 to 2021 and identified baseline factors associated with vaccine initiation (≥1 dose) or series completion (3 doses) among participants who were unvaccinated or partially vaccinated at baseline.

Methods: We recruited sexually-active GBM aged ≥ 16 years in Montreal, Toronto, and Vancouver, Canada, from 02/2017 to 08/2019 and followed them over a median of 12 months (interquartile range = 12-13 months).

Impact of the first vaccine dose on COVID-19 and its complications in long-term care facilities and private residences for seniors in Québec, Canada.

Background: Residents of long-term care facilities (LTCFs) and private residences for seniors (PRSs) were given priority for vaccination against coronavirus disease 2019 (COVID-19). Given the shortage of vaccine in the winter of 2021, the recommended postponing the administration of second doses to ensure more rapid and widespread administration of first doses. The objective of this study was to measure the impact of first-dose vaccination on 1) the incidence of cases and complications in LTCFs and PRSs and 2) the frequency of outbreaks in LTCFs.

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.

Single-Dose Messenger RNA Vaccine Effectiveness Against Severe Acute Respiratory Syndrome Coronavirus 2 in Healthcare Workers Extending 16 Weeks Postvaccination: A Test-Negative Design From Québec, Canada.

Background: In Canada, first and second doses of messenger RNA (mRNA) vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were uniquely spaced 16 weeks apart. We estimated 1- and 2-dose mRNA vaccine effectiveness (VE) among healthcare workers (HCWs) in Québec, Canada, including protection against varying outcome severity, variants of concern (VOCs), and the stability of single-dose protection up to 16 weeks postvaccination.

Methods: A test-negative design compared vaccination among SARS-CoV-2 test-positive and weekly matched (10:1), randomly sampled, test-negative HCWs using linked surveillance and immunization databases.

Sexual behavior, clinical outcomes and attendance of cervical cancer screening by HPV vaccinated and unvaccinated sexually active women.

Concerns were raised about HPV vaccination possibly leading to riskier sexual behavior. We assessed sexual behaviors, risk of sexually transmitted infection, and attendance to cervical cancer screening by HPV vaccinated and unvaccinated young women. In this analysis, 1475 questionnaires completed by women aged 17-29 years were included.

A systematic literature review of the recombinant subunit herpes zoster vaccine use in immunocompromised 18-49 year old patients.

Background: The adjuvanted recombinant zoster vaccine (RZV) is indicated for prevention of herpes zoster (HZ) in adults aged ≥50 years. Questions regarding the use of RZV in immunocompromised patients < 50-year-old, who are at increased risk for HZ, were raised.

Objectives: The objective of this systematic review was to consolidate existing evidences on safety, immunogenicity and efficacy of RZV in immunocompromised adults aged 18-49 years.

Participation in an action research project on vaccine services for children: relationship with vaccine delays.

Multicomponent interventions are effective in improving vaccine coverage. However, few studies have assessed their effect on timely vaccination. The aim of this study was to compare the proportion of children with vaccine delays at 2- and 12-month visits according to whether or not health centers have participated in an action research project on the organization of vaccination services for 0-5-year-olds.

Children vaccination coverage surveys: Impact of multiple sources of information and multiple contact attempts.

Background: Monitoring vaccination coverage is an essential component of vaccination program evaluation. In Québec (Canada), children vaccination coverage surveys are conducted every two years since 2006. The objectives of this study were to evaluate the impact of supplementing data based on vaccination booklets with data from vaccine providers, on the final estimated vaccination coverage and to compare vaccination coverage between respondents to each survey contact attempt.