Publications by authors named "Melanie Drolet"
Article Synopsis
- - The study investigates the cost-effectiveness of expanding HPV vaccination to U.S. adults aged 27-45, particularly those at higher risk for HPV-related diseases, by modeling the potential outcomes over a 100-year timeframe.
- - It found that vaccinating mid-adults generally costs more per life year gained compared to vaccinating younger individuals, with varying costs and effectiveness depending on risk factors like number of sexual partners and recent relationship status.
- - The most efficient strategy identified was vaccinating women who have recently separated and have many lifetime partners, offering a lower cost per quality-adjusted life-year and fewer individuals needed to vaccinate to prevent one cancer case.
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.
Article Synopsis
- The study simulated how different HPV vaccination strategies affect cervical cancer cases over 85 years, focusing on switching from a 2-dose to a 1-dose program.
- It utilized two mathematical models to predict the outcomes based on different scenarios, such as introducing a 1-dose vaccination and varying age groups for vaccination.
- Results showed that switching to a 2-dose program in 2036 could yield similar health benefits to starting with a 1-dose vaccine with no effectiveness loss, indicating potential efficiency for countries considering the 1-dose option.
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%).
Efficacy and immunogenicity of a single dose of human papillomavirus vaccine compared to multidose vaccination regimens or no vaccination: An updated systematic review of evidence from clinical trials.
Vaccine X
August 2024
Objectives: This study systematically reviewed the published literature from clinical trials on the efficacy and immunogenicity of single-dose HPV vaccination compared to multidose schedules or no HPV vaccination.
Methods: Four databases were searched for relevant articles published from Jan-1999 to Feb-2023. Articles were assessed for eligibility for inclusion using pre-defined criteria.
Background: Understanding the role of naturally acquired (i.e., infection-induced) human papillomavirus (HPV) antibodies against reinfection is important given the high incidence of this sexually transmitted infection.
View Article and Find Full Text PDFBackground: Given the accumulating evidence that one-dose vaccination could provide high and sustained protection against human papillomavirus (HPV) infection and related diseases, we examined the population-level effectiveness and efficiency of one-dose HPV vaccination of girls compared with two-dose vaccination, using mathematical modelling.
Methods: In this mathematical modelling study, we used HPV-ADVISE LMIC, an individual-based transmission-dynamic model independently calibrated to four epidemiologically diverse low-income and middle-income countries (LMICs; India, Nigeria, Uganda, and Viet Nam). We parameterised and calibrated the model using sexual behaviour and epidemiological data identified from international population-based datasets and the literature.
Background: To eliminate cervical cancer as a public health problem, the World Health Organization had recommended routine vaccination of adolescent girls with two doses of the human papillomavirus (HPV) vaccine before sexual initiation. However, many countries have yet to implement HPV vaccination because of financial or logistical barriers to delivering two doses outside the infant immunisation programme.
Methods: Using three independent HPV transmission models, we estimated the long-term health benefits and cost-effectiveness of one-dose versus two-dose HPV vaccination, in 188 countries, under scenarios in which one dose of the vaccine gives either a shorter duration of full protection (20 or 30 years) or lifelong protection but lower vaccine efficacy (e.
Article Synopsis
- The WHO suggests extending the interval between HPV vaccine doses to 3-5 years to manage supply issues, but concerns exist about potential infections, lower vaccination rates, and tracking vaccinated individuals.
- A study used a dynamic model to analyze the consequences of these concerns on HPV vaccine effectiveness in four low- to middle-income countries: India, Viet Nam, Uganda, and Nigeria.
- Results indicate that a two-dose HPV vaccination schedule could significantly reduce cervical cancer rates by 79-86% over a century compared to non-vaccination, even when implementing a 5-year extended schedule.
Background: Human papillomavirus (HPV) vaccines were first licensed as a three-dose series. Two doses are now widely recommended in some age groups; there are data suggesting high efficacy with one dose. We updated a systematic literature review of HPV vaccine effectiveness by number of doses in observational studies.
View Article and Find Full Text PDFBackground: Vaccines have been demonstrated to protect against high-risk human papillomavirus infection (HPV), including HPV-16/18, and cervical lesions among HIV negative women. However, their efficacy remains uncertain for people living with HIV (PLHIV).We systematically reviewed available evidence on HPV vaccine on immunological, virological, or other biological outcomes in PLHIV.
View Article and Find Full Text PDFBackground: 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).
Article Synopsis
- The study examines the changes in social contacts in Quebec, Canada, before and during the COVID-19 pandemic, revealing a significant decrease in interactions due to physical distancing measures.
- Prior to the pandemic, participants reported an average of 8 social contacts per day, which dropped to 3 during the initial lockdown in spring 2020 and remained low throughout the pandemic.
- The research indicates that all demographic groups experienced reductions in contacts, particularly in work, leisure, and home visit situations, emphasizing the influence of public health restrictions.
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.
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.
Background: Introduction of human papillomavirus (HPV) vaccination has been slow in low-income and middle-income countries (LMICs) because of resource constraints and worldwide shortage of vaccine supplies. To help inform WHO recommendations, we modelled various HPV vaccination strategies to examine the optimal use of limited vaccine supplies and best allocation of scarce resources in LMICs in the context of the WHO global call to eliminate cervical cancer as a public health problem.
Methods: In this mathematical modelling analysis, we developed HPV-ADVISE LMIC, a transmission-dynamic model of HPV infection and diseases calibrated to four LMICs: India, Vietnam, Uganda, and Nigeria.
Objective: The North American coronavirus disease-2019 (COVID-19) epidemic exhibited distinct early trajectories. In Canada, Quebec had the highest COVID-19 burden and its earlier March school break, taking place two weeks before those in other provinces, could have shaped early transmission dynamics.
Methods: We combined a semi-mechanistic model of SARS-CoV-2 transmission with detailed surveillance data from Quebec and Ontario (initially accounting for 85% of Canadian cases) to explore the impact of case importation and timing of control measures on cumulative hospitalizations.
Background: WHO is developing a global strategy towards eliminating cervical cancer as a public health problem, which proposes an elimination threshold of four cases per 100 000 women and includes 2030 triple-intervention coverage targets for scale-up of human papillomavirus (HPV) vaccination to 90%, twice-lifetime cervical screening to 70%, and treatment of pre-invasive lesions and invasive cancer to 90%. We assessed the impact of achieving the 90-70-90 triple-intervention targets on cervical cancer mortality and deaths averted over the next century. We also assessed the potential for the elimination initiative to support target 3.
View Article and Find Full Text PDFBackground: The WHO Director-General has issued a call for action to eliminate cervical cancer as a public health problem. To help inform global efforts, we modelled potential human papillomavirus (HPV) vaccination and cervical screening scenarios in low-income and lower-middle-income countries (LMICs) to examine the feasibility and timing of elimination at different thresholds, and to estimate the number of cervical cancer cases averted on the path to elimination.
Methods: The WHO Cervical Cancer Elimination Modelling Consortium (CCEMC), which consists of three independent transmission-dynamic models identified by WHO according to predefined criteria, projected reductions in cervical cancer incidence over time in 78 LMICs for three standardised base-case scenarios: girls-only vaccination; girls-only vaccination and once-lifetime screening; and girls-only vaccination and twice-lifetime screening.
Efficacy and immunogenicity of a single dose of human papillomavirus vaccine compared to no vaccination or standard three and two-dose vaccination regimens: A systematic review of evidence from clinical trials.
Vaccine
February 2020
Objectives: This study aimed to systematically review the literature on the efficacy and immunogenicity of single-dose HPV vaccination compared to no vaccination or multi-dose schedules among vaccine trial participants.
Methods: Medline, EMBASE, Global Health Database and Cochrane Central Register of Controlled Trials were searched for publications and conference abstracts (dated January 1999-August 2018) using MeSH and non-MeSH terms for human papillomavirus AND vaccines AND (immunogenicity OR efficacy/effectiveness) AND dosage. Search results were screened against pre-specified eligibility criteria.
Background: The aim of this study was to evaluate the wage losses incurred by spouses of women with nonmetastatic breast cancer in the 6 months after the diagnosis.
Methods: A prospective cohort study of spouses of women diagnosed with nonmetastatic breast cancer who were recruited in 8 hospitals in the province of Quebec (Canada) was performed. Information for estimating wage losses was collected by telephone interviews conducted 1 and 6 months after the diagnosis.
Background: In the United States, the routine age for human papillomavirus (HPV) vaccination is 11 to 12 years, with catch-up vaccination through age 26 years for women and 21 years for men. U.S.
View Article and Find Full Text PDFBackground: Two vaccines against herpes zoster are currently authorized for use in Canada: the recombinant subunit zoster vaccine and live attenuated zoster vaccine. We compared the effectiveness and cost-effectiveness of these 2 vaccines.
Methods: We used a decision analytic static cohort model parametrized with Canadian epidemiologic and economic data.
Background: More than 10 years have elapsed since human papillomavirus (HPV) vaccination was implemented. We did a systematic review and meta-analysis of the population-level impact of vaccinating girls and women against human papillomavirus on HPV infections, anogenital wart diagnoses, and cervical intraepithelial neoplasia grade 2+ (CIN2+) to summarise the most recent evidence about the effectiveness of HPV vaccines in real-world settings and to quantify the impact of multiple age-cohort vaccination.
Methods: In this updated systematic review and meta-analysis, we used the same search strategy as in our previous paper.