Expert Review of Vaccines最新文献

Introduction: This systematic review aims to assess determinants of vaccine hesitancy (VH) among healthcare professionals, to identify knowledge gaps and inform targeted training programs.

Research design and methods: A systematic search of PubMed and Scopus was conducted in February 2024. PRISMA criteria were applied, and methodological quality was assessed using a cross-sectional study evaluation tool. Studies addressing HCWs' VH determinants, including knowledge, attitudes, communication, and organizational factors, were included.

Results: Out of 1394 records, 221 articles were included. Reported prevalence of VH among HCWs varied across studies, reflecting differences in professional roles, settings, and vaccines studied. Key determinants included gaps in knowledge, personal beliefs, organizational barriers, and communication skills. The review highlights the importance of evidence-based information, continuing education, and effective communication in addressing VH among HCWs.

Conclusions: Educational and organizational interventions are essential to improve HCWs' knowledge, attitudes, and practices regarding vaccination. Strengthening vaccine education, fostering effective communication, and addressing organizational challenges can reduce hesitancy and support HCWs in promoting vaccination among patients. Future initiatives should consider the diversity of educational settings, professional roles, and training requirements across healthcare systems.

Background: Significant residual burden of invasive pneumococcal disease (IPD) is attributable to Streptococcus pneumoniae serotypes not included in any available vaccines in Germany. This study quantified the burden of invasive pneumococcal disease attributable to PCV21 and PCV20 serotypes among German adults.

Research design and methods: A published state-transition Markov model estimated the lifetime cases, deaths, and direct costs (2023 Euros) of IPD by age (18-49, 50-59, and 60 years and older) and risk group (low-risk, at-risk, and high-risk) in Germany. One-way sensitivity analysis on PCV21 cost was conducted.

Results: Across all age groups, there were 50,462 more IPD cases and 8895 deaths attributable to the serotypes in PCV21 compared to PCV20. The eight unique serotypes to PCV21 accounted for approximately 22% of disease. Higher direct costs were associated with PCV21 serotypes versus PCV20 serotypes (€505,094,685 versus €389,835,550, respectively). Discount rate of costs was the most influential input.

Conclusions: Serotypes in PCV21 compared to PCV20 are associated with greater health and economic burden in Germany, primarily driven by the eight unique serotypes included in PCV21 and no other licensed vaccine. Including PCV21 in the national German vaccination guidelines may substantially reduce IPD-related health and economic burden among adults.

Introduction: Chronic infections with Trypanosoma cruzi can lead to Chagas disease, with cardiac and/or digestive debilitating manifestations. There has been a renewed interest in vaccine development against this neglected tropical disease in the past decades.

Areas covered: Vaccines ranging from live attenuated to recombinant subunit, nucleic acid, bacterial, viral and algal vectors, targeting various parasite antigens have been tested in mice as preventative and therapeutic vaccine against clinical disease progression as well as in the context of pregnancy to prevent congenital transmission and other adverse birth outcomes. A few of these vaccine candidates have been tested in dogs and non-human primates. Further clinical development faces several challenges associated with slow disease progression and the lack of biomarkers, the diversity of parasite strains, complex host-parasite relationship, among others.

Expert opinion: Pre-clinical studies broadly support the clinical development of a Chagas disease vaccine, particularly for a therapeutic vaccine. Synergy with drug development efforts, which face many of the same challenges, may provide new opportunities to strengthen clinical development and trials of drugs, vaccines and combined therapies.

Background: Chronic obstructive pulmonary disease (COPD) increases the risk of severe respiratory syncytial virus (RSV)-related disease. This analysis evaluated the potential public health impact and cost-effectiveness of RSV vaccination with a single dose of adjuvanted RSVPreF3 vaccine over five years in people aged 60-74 years with COPD in Italy.

Research design and methods: A static multi-cohort Markov model estimated RSV-related events, costs, and quality-adjusted life-years (QALY) over five years in people aged 60-74 years with COPD in Italy vaccinated with one dose of adjuvanted RSVPreF3, versus no vaccination. Vaccine efficacy and waning data were based on AReSVi-006 Phase III clinical trial results. Other input data came from published literature and official databases. Sensitivity analyses were conducted.

Results: A single dose of adjuvanted RSVPreF3 vaccine (75% coverage) was projected to reduce RSV-related acute respiratory infections by 29% and RSV-related hospitalizations and deaths by 38% among patients with COPD aged 60-74 years in Italy. The incremental cost-effectiveness ratio (health system perspective) was €1,306/QALY.

Conclusions: These results indicated that a single dose of adjuvanted RSVPreF3 vaccine in patients with COPD aged 60-74 years in Italy is a cost-effective preventive option that could potentially reduce RSV-related disease burden and costs over five years.

Introduction: Typhoid fever is widespread in developing countries. Most typhoid vaccines have gone into some disrepute for their substantial side effects and low efficacy. The latest typhoid vaccines use Salmonella's Vi-capsular polysaccharide (Vi-CPS) conjugated to a protein carrier. The WHO recommends a single typhoid conjugate vaccine (TCV) dose at six months in endemic countries. However, this schedule is contested.

Areas covered: The molecular structure of Vi-CPS, emerging Vi capsule variants, the impact of de-O acetylation on vaccine immunogenicity, the key features of an effective Vi-PS conjugate vaccine, the immunological correlates of protection, the impact of boosting by a TCV on Vi-antibodies, and knowledge gaps were examined. We have also reviewed TCV efficacy and durability data. Our analysis shows that the vaccines are effective, although immunity wanes after five years, especially in children under two. We also offered ways to improve TCV efficacy and briefly discussed new typhoid vaccine development.

Expert opinion: We believe the TCV schedule necessitates revision. Extending the primary immunization age or incorporating a booster upon school enrollment are reasonable alternatives. Region-specific or universal modifications require further deliberation.

Background: China implemented diverse varicella vaccination strategies from 2012 to 2022, with unclear protective effects. The study aimed to evaluate the effects of two varicella vaccination (VarV) (the two-dose self-paid VarV and the two-dose free VarV) strategies implemented in Guangdong Province, China.

Research design and methods: We collected data on varicella cases and doses administered to children aged 0-14 in Guangzhou, Shenzhen, and Foshan from 2012 to 2022. Using Bayesian Structured Time Series (BSTS) model, we estimated the effects of the two VarV strategies in Guangzhou and Shenzhen starting from 2018, by referencing Foshan.

Results: Post-implementation of the two-dose self-paid VarV strategy 36,749 (95% CI: 29070, 44428) and 24,179 (95% CI: 16400, 31958) varicella cases were averted in Guangzhou and Shenzhen, with a protection rate of 41.8% (95% CI: 36.3%, 46.5%) and 38.9% (95% CI: 30.2%, 45.7%), respectively. After the adoption of the two-dose free VarV strategy, a substantial relative protection rate of 64.2% (95% CI: 58.0%, 68.7%) in varicella cases was observed in Shenzhen, with 38,828 (95% CI: 29979, 47677) cases averted by 2022.

Conclusions: The two-dose VarV strategies have proven highly effective in reducing varicella incidence. The experience in Shenzhen underscores the benefits of a two-dose free VarV strategy.

Background: Health Canada approved two new pneumococcal conjugate vaccines (PCV), 15-valent (PCV15) and 20-valent (PCV20), and we assessed their cost-effectiveness for older Ontarians.

Research design and methods: We conducted a cost-utility analysis using an individual-level state transition model to compare one dose of PCV (alone or in series with PPV23) with PPV23-only. We estimated incremental cost-effectiveness ratios (ICERs) expressed in costs (C$2022) per quality-adjusted life year (QALY) from the healthcare payer perspective, discounted at 1.5% annually.

Results: A sequential comparison of vaccinations with no indirect effect from childhood vaccination resulted in an ICER of $44,324/QALY for PCV15-alone compared to PPV23-only, and $70,751/QALY for PCV20-alone versus PCV15-alone. None of the PCV15/20 combined with PPV23 programs were cost-effective at a C$50,000/QALY threshold. PCV20 alone had an ICER of C$46,961/QALY compared to PPV23-only. When considering indirect effects, PCV15/20 alone or in series with PPV23 were not cost-effective. ICERs were mostly influenced by vaccine characteristics (effectiveness, waning, cost) and the incidence of pneumococcal community-acquired pneumonia.

Conclusions: Vaccinating older adults with PCV15/20 likely reduces burden of pneumococcal disease and would be cost-effective initially, but is expected to be less economically attractive in the longer term when herd immunity benefits from childhood vaccination programs are considered.

Background: The U.S. Advisory Committee on Immunization Practices recommends use of bivalent stabilized prefusion F subunit vaccine (RSVpreF) among pregnant persons to protect their infants against lower respiratory tract illness due to RSV (RSV-LRTI).

Research design and methods: Using a cohort model depicting clinical outcomes and economic costs of RSV acute respiratory infection (RSV-ARI) among US infants from birth to age 1 year, we evaluated the impact of seasonally administered maternal RSVpreF versus no intervention. Outcomes included cases of medically attended RSV-ARI, RSV-related deaths, medical costs, and indirect costs. Costs were reported in 2023 US$.

Results: Among the 3.7 million US infants aged <12 months each year, a total of 1,148,967 RSV-ARI cases (hospital: 48,384; emergency department [ED]: 246,118; outpatient clinic [OC]: 854,465) were projected to occur, yielding total annual costs of $2.4 billion (direct: $1.7B; indirect: $0.7B). With 54.9% uptake, RSVpreF would prevent 89,908 cases (hospital: 10,308; ED: 20,538; OC: 59,062), corresponding with a $368 million decrease (direct: $286 M; indirect: $81 M) in total 1-year costs.

Conclusion: Even with limited uptake and without considering benefits to pregnant persons or reductions in RSV-related sequelae, maternal vaccination with RSVpreF would substantially reduce the public health and economic burden of RSV-ARI in US infants.