•Immunocompromised patients are at increased risk for herpes zoster (HZ) and its complications.•The recombinant zoster vaccine (RZV) is indicated for prevention of HZ in adults ...aged ≥ 50 years.•Consolidated data show RZV has an acceptable safety profile in ≥ 18 y.o. immunocompromised patients.•No exacerbation of underlying diseases was observed in RZV groups’ as compared to placebo.•RZV efficacy against HZ in immunocompromised ≥ 18 y.o. patients varied between 67 and 87%
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.
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.
Four databases were searched. Preferred Reporting Items for Systematic review and Meta-Analysis Protocols (PRISMA-P) guidelines were followed. Screening and classification of search items was performed using the web-based platform DistillerSR.
The search identified 1389 potentially relevant records. Six studies fulfilled inclusion criteria. The proportion of patients aged 18–49 varied between 23 and 62%. Pain at injection site (98.6%) and fatigue (75.3%) were the most common adverse events. The proportion of patients reporting serious adverse events (SAEs) ranged between 8.1 and 30.8% in RZV and between 4.1 and 36.5% in placebo groups. SAEs deemed related to vaccination were reported in < 1% of patients in both RZV and placebo groups. The proportion of patients that experienced clinically significant underlying disease-related events ranged between 0.0 and 20.0% in RZV and 0.0 and 26.7% in placebo groups.
The humoral and cell-mediated immune response rate ranged between 65.4 and 96.2% and 50.0–93.0%, respectively. Vaccine efficacy in hematopoietic stem cell transplant patients was 72% (95%CI, 39–88%) in 18–49-year-olds and 67% (95%CI, 53–78%) in ≥ 50-year-olds (median follow-up 21 months). Vaccine efficacy in ≥ 18-year-old patients with hematologic malignancies was estimated at 87.2% (95%CI, 44.3–98.6%) up to 13 months post-vaccination.
Results suggest that RZV has an acceptable safety profile and induces immunity in an important proportion of ≥ 18-year-old immunocompromised patients. Longer follow-up studies are warranted to assess the duration of RZV induced immunity in immunocompromised patients.
Older adults are at high risk for influenza-related complications including worsening frailty and function. We surveyed older Canadians to explore the impact of influenza and determine how influenza ...knowledge influences vaccination decision-making.
We disseminated an online survey through a national polling panel. The survey included questions about the respondents' influenza vaccination practices and knowledge about influenza. Using validated measures, they reported their frailty and functional status prior to the 2016/17 influenza season, during illness (if applicable), and following the season. Regression analyses were used to examine predictors of poor functional outcomes.
Five thousand and fourteen adults aged 65 and older completed the survey; mean age was 71.3 ± 5.17 years, 42.6% had one or more chronic conditions, 7.8% were vulnerable and 1.8% were frail. 67.9% reported receiving last season's influenza vaccine. Those who rarely/never receive the influenza vaccine were significantly less likely to correctly answer questions about influenza's impact than those who receive the vaccine more consistently. Of the 1035 (21.5%) who reported experiencing influenza or influenza-like illness last season, 40% indicated a recovery longer than 2 weeks, and one-fifth had health and function declines during this time. Additionally, 3.1% of those afflicted "never fully recovered". Older age, significant trouble with memory and having influenza/ILI were among the independent predictors of persistent declines in health and function.
Given that frailty and function are important considerations for older adults' well-being and independence, healthcare decision-makers must understand the potential for significant temporary and long-term impacts of influenza to make informed vaccine-related policies and recommendations.
HPV vaccination decision-making is a complex process that is influenced by multiple psychosocial determinants. Given the change in policy recommendation to include males in routine HPV vaccination, ...our goals were to assess the HPV vaccination uptake in Canada, to understand where Canadian parents were situated in the HPV vaccine decision-making process for their son, how they changed over time and which psychosocial determinants were relevant for this process.
We used an online survey methodology and collected data from a nationally representative sample of Canadian parents of boys aged 9-16 at baseline (T1, February 2014) and at 9 months' follow-up (T2). Our analyses were guided by the Precaution Adoption Process Model (PAPM), a theoretical health behavior model that classifies parents in one of six stages: unaware, unengaged, undecided, decided not to vaccinate, decided to vaccinate and those who had already vaccinated their sons. Rigorous methods were used to filter out careless responders: response variance, bogus items, psychometric antonyms and psychometric synonyms.
At T1 and T2, we received 3,784 and 1,608 respectively completed questionnaires; after data cleaning 3,117 (T1) and 1,427 (T2) were retained. Less than 3% of boys were vaccinated at both time points. At both T1 and T2, most parents (over 70%) belonged to the earlier vaccination adoption stages: 57% were unaware (T1) and 15.3% (T2); 20.9% were unengaged (T1) and 32.4% (T2); and 9.1% were undecided (T1) and 25.2% (T2). At follow-up, 37.7% of participants did not move from their initial PAPM decision-making stage. Most parents (55%) preferred to receive information from their healthcare provider (HCP) but only 6% (T1) and 12% (T2) had actually spoken with a HCP about the HPV vaccine for their son.
HPV vaccination uptake in Canadian boys was very low in the absence of a publicly funded HPV vaccination programs for boys. Optimal HPV information preferences were identified and can be used in interventions to increase HPV knowledge and increase HPV vaccine uptake. Intentions to vaccinate or planning to speak to one's HCP did not translate into action for most parents over the 9-month follow up; this finding is critical to consider to inform implementation strategies. Methodological challenges are described and suggestions for future research are offered.
ABSTRACTBACKGROUNDTwo 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. METHODSWe used a decision analytic static cohort model parametrized with Canadian epidemiologic and economic data. We performed the economic analysis from the health care system perspective, using a lifetime horizon and a 3% discount rate for costs and benefits. The primary outcome was the incremental cost per quality-adjusted life-year (QALY) gained, relative to no vaccination. We ran 30 000 simulations varying all model parameters, including vaccine costs, efficacy and waning. RESULTSThe number needed to vaccinate (NNV) was higher for the live attenuated zoster vaccine than for the recombinant subunit zoster vaccine for all herpes zoster–related events at all ages. For example, in persons exactly 65 years old, for herpes zoster, median NNV was 21 (90% uncertainty interval UI 13–31) versus 8 (90% UI 6–18), and for postherpetic neuralgia, NNV was 64 (90% UI 33–93) versus 31 (90% UI 23–73). For the recombinant vaccine, the median cost-effectiveness ratios varied between cost-saving and $25 881 per QALY gained for adults aged 50 years or older. For the live vaccine, the cost-effectiveness ratios varied between cost-saving and $130 587 per QALY gained and were less than $45 000 per QALY gained only for those 65 to 75 years old. Given its higher efficacy, we estimated that the cost for the complete series of the recombinant vaccine could be $150 to $200 more than the cost of the live vaccine and still be considered cost-effective. INTERPRETATIONOur model predicted that the recombinant subunit zoster vaccine is likely cost-effective in Canada for adults 60 years or older, and is likely more cost-effective than live attenuated zoster vaccine. These results have informed updated national and provincial recommendations on herpes zoster vaccination.
Abstract
Background
Influenza is associated with a decline in functional abilities among Canadian older adults, although specific impacts on daily life have not been fully explored.
Methods
In August ...2019 and May 2020, we conducted surveys of Canadian adults 50-64 years and 65 years and older through an online market research platform. The survey included questions about the impact of diagnosed influenza or self-reported influenza-like-illness (ILI) on working, volunteering and caregiving.
Results
We surveyed 1006 adults in the 50-64 year age group about the 2018/19 season and 1001 about the 2019/20 season. In the 65 years and older age group, we surveyed 3548 and 3500 individuals about the 2018/19 and 2019/20 influenza seasons, respectively. In each season, nearly two-thirds of individuals 50-64 years with influenza/ILI were employed; 51.7% reported absenteeism in 2018/19 and 53.6% in 2019/20. Of the 20% of individuals 65 years and older who were employed, 47.0% of those with influenza/ILI were absent while ill in 2018/19 (39.8% in 2019/20). In 2018/2019, 29.6% of respondents 50-64 years old with influenza/ILI identified as volunteers (29.3% in 2019/2020). In both seasons, nearly half were unable to do so while ill. Of the 164 (32.7%) individuals 65 years and older who volunteered during the 2018/19 season, 80 (48.8%) did not while ill; 224 (37.3%) respondents volunteered in the 2019/20 season, and half were absent while ill. Of those 50-64 years with influenza/ILI, 97 (42.2%) and 57 (22.2%) were caregivers in 2018/19 and 2019/20, respectively. In 2018/19 and 2019/20, 40 (41.2%) and 28 (49.1%) caregivers were unable to provide care when ill, respectively. Of those with influenza/ILI in the 65 years and older age group, 123 (24.6%) and 162 (27.0%) were caregivers in 2018/19 and 2019/20, respectively. In 2018/19, 18 (14.6%) caregivers with influenza/ILI did not provide care while ill (42 25.9% in 2019/20).
Discussion
In Canadian older adults, influenza and ILI had notable impacts on ability to volunteer and provide care across two recent seasons. Optimization of influenza prevention in this population may yield important societal benefits.
Background: In 2008, a school-based human papilloma virus (HPV) vaccination program was implemented in the province of Québec. Grade 4 girls (9–10 years old) are routinely vaccinated and grade 9 to ...12 girls (14–17 years old) were eligible for the catch-up vaccination. Vaccine coverage of the targeted cohorts was estimated at 76–81%. To assess if HPV vaccination is associated with an increase in GBS hospitalisation, we compared the hospitalization rates of GBS in HPV vaccination targeted and non-targeted groups. Methods: Hospital discharge records with a GBS code as the main diagnosis during the 1999–2014 period were retrieved. Incidence rates according to program eligibility were computed and adjusted relative risk in the targeted groups was estimated by Poisson regression. Results: The overall incidence rate in the 7 to 17 year-olds was 0.73/100,000 p-y. There was no increase in GBS incidence in HPV vaccination targeted groups (adjusted IRR = 0.81, 95%CI: 0.29–2.26). Conclusion: No signal of increase GBS hospitalisation incidence in the HPV-vaccine targeted group was detected in the hospitalisation database.
Background. Cases of infection due to a novel swine-origin variant of influenza A virus subtype H3N2 (H3N2v) have recently been identified in the United States, primarily among children. We estimate ...levels of cross-reactive antibody to H3N2v by age and assess whether seasonal trivalent inactivated influenza vaccine (TIV), with or without adjuvant, may increase seroprotection. Methods. Antibody to H3N2v was assessed by hemagglutination inhibition (HI) assay and, for a subset, also by microneutralization assay. Seroprevalence and seroprotection were defined as an HI titer of ≥40, and levels were compared with those for ancestral and contemporary human strains. The analysis included 1116 sera collected during fall 2010, corresponding to approximately 100 sera per decade of life. Vaccine-induced antibody levels were also assessed in sera from 136 children aged <10 years and 65 adults aged 20-59 years before and after receipt of 2010-2011 split TIV and in sera from 182 elderly individuals aged > 65 years before and after receipt of 2011-2012 split TIV (for 31 individuals), MF59-adjuvanted TIV (for 72), or unadjuvanted subunit TIV (for 79). Results. The overall prevalence of HI titers of ≥40 against A(H3N2) v was 25%. No children aged <5 years and <20% of individuals aged ≤14 years or ≥40 years had an HI titer of ≥40. Conversely, among individuals aged 15-39 years, half of teens and adults showed H3N2v seroprotection. Following TIV receipt, <15% of individuals in any vaccine group developed a 4-fold increase in antibody level. Conclusions. A substantial proportion of adolescents and young adults have cross-reactive antibody against emerging H3N2v, whereas children and older adults show broad susceptibility. Recent formulations of TIV do not substantially increase seroprotection. A specific vaccine would be needed if H3N2v establishes epidemic spread.
Public health vaccination recommendations for COVID-19 primary series and boosters in previously infected individuals differ worldwide. As infection with SARS-CoV-2 is often asymptomatic, it remains ...to be determined if vaccine immunogenicity is comparable in all previously infected subjects. This study presents detailed immunological evidence to clarify the requirements for one- or two-dose primary vaccination series for naturally primed individuals. The main objective was to evaluate the immune response to COVID-19 mRNA vaccination to establish the most appropriate vaccination regimen to induce robust immune responses in individuals with prior SARS-CoV-2 infection. The main outcome measure was a functional immunity score (zero to three) before and after vaccination, based on anti-RBD IgG levels, serum capacity to neutralize live virus and IFN-γ secretion capacity in response to SARS-CoV-2 peptide pools. One point was attributed for each of these three functional assays with response above the positivity threshold. The immunity score was compared based on subjects' symptoms at diagnosis and/or serostatus prior to vaccination. None of the naïve participants (n=14) showed a maximal immunity score of three following one dose of vaccine compared to 84% of the previously infected participants (n=55). All recovered individuals who did not have an immunity score of three were seronegative prior to vaccination, and 67% had not reported symptoms resulting from their initial infection. Following one dose of vaccine, their immune responses were comparable to naïve individuals, with significantly weaker responses than individuals who were symptomatic during infection. These results indicate that the absence of symptoms during initial infection and negative serostatus prior to vaccination predict the strength of immune responses to COVID-19 mRNA vaccine. Altogether, these findings highlight the importance of administering the complete two-dose primary regimen and following boosters of mRNA vaccines to individuals who experienced asymptomatic SARS-CoV-2 infection.
In order to inform meningococcal disease prevention strategies, we analysed the epidemiology of invasive meningococcal disease (IMD) in the province of Quebec, Canada, 10 years before and 10 years ...after the introduction of serogroup C conjugate vaccination.
IMD cases reported to the provincial notifiable disease registry in 1991-2011 and isolates submitted for laboratory surveillance in 1997-2011 were analysed. Serogrouping, PCR testing and assignment of isolates to sequence types (ST) by using multilocus sequence typing (MLST) were performed.
Yearly overall IMD incidence rates ranged from 2.2-2.3/100,000 in 1991-1992 to 0.49/100,000 in 1999-2000, increasing to 1.04/100,000 in 2011. Among the 945 IMD cases identified by laboratory surveillance in 1997-2011, 68%, 20%, 8%, and 3% were due to serogroups B, C, Y, and W135, respectively. Serogroup C IMD almost disappeared following the implementation of universal childhood immunization with monovalent C conjugate vaccines in 2002. Serogroup B has been responsible for 88% of all IMD cases and 61% of all IMD deaths over the last 3 years. The number and proportion of ST-269 clonal complex has been steadily increasing among the identified clonal complexes of serogroup B IMD since its first identification in 2003, representing 65% of serogroup B IMD in 2011. This clonal complex was first introduced in adolescent and young adults, then spread to other age groups.
Important changes in the epidemiology of IMD have been observed in Quebec during the last two decades. Serogroup C has been virtually eliminated. In recent years, most cases have been caused by the serogroup B ST-269 clonal complex. Although overall burden of IMD is low, the use of a vaccine with potential broad-spectrum coverage could further reduce the burden of disease. Acceptability, feasibility and cost-effectiveness studies coupled with ongoing clinical and molecular surveillance are necessary in guiding public policy decisions.
Influenza vaccination is an important public health intervention for older adults, yet vaccination rates remain suboptimal. We conducted an online survey of Canadians ≥ 65 years to explore ...satisfaction with publicly-funded standard-dose influenza vaccines, and perceptions of the need for a more effective product. They were provided with information about currently approved influenza vaccines, and were asked about their preferences should all formulations be available for free, and should the recently approved high-dose (HD) vaccine for seniors be available at a cost. From March to April 2017, 5014 seniors completed the survey; mean age was 71.3 ± 5.17 years, 50% were female, and 42.6% had one or more chronic conditions. 3403 (67.9%) had been vaccinated against influenza in the 2016/17 season. Of all respondents, 3460 (69%) were satisfied with the standard-dose influenza vaccines, yet 3067 (61.1%) thought that a more effective vaccine was/may be needed. If HD was only available at a cost, 1426 (28.4%) respondents would consider it, of whom 62.9% would pay $20 or less. If all vaccines were free next season, 1914 (38.2%) would opt for HD (including 12.2% of those who previously rejected influenza vaccines), 856 (17.1%) would choose adjuvanted vaccine, and 558 (11.1%) standard-dose vaccine. 843 (16.8%) of respondents were against vaccines, 451 (9.0%) had no preference and 392 (7.8%) were uncertain. Making this product available through publicly funded programs may be a strategy to increase immunization rates in this population.
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