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.

Introduction: The saponin-based Matrix-M adjuvant induces potent and durable immunity through producing long-lasting memory B-cells and broad-based T-cell immunity, across a variety of vaccine platforms. Matrix-M-adjuvanted vaccines have a history of successful development for protection against a broad range of infectious diseases with high public health urgency. Two authorized Matrix-M-adjuvanted vaccines, NUVAXOVID (COVID-19) and R21/Matrix-M (Plasmodium falciparum malaria), have been administered to >10 million people worldwide.

Areas covered: This review is a comprehensive evaluation of published reactogenicity and safety data from 66 clinical trials and post-marketing studies of Matrix-M-adjuvanted COVID-19, seasonal influenza, combination COVID-19-influenza (CIC), and malaria vaccines retrieved from PubMed and Embase with no restricted start date and last search on 1 November 2025.

Expert opinion: 64,101 participants received ≥1 Matrix-M-adjuvanted vaccine dose (143,170 doses): 55,939 COVID-19, 2477 influenza, 1422 CIC, and 4263 malaria vaccines. All authorized and candidate vaccines within each disease area were well-tolerated, including among a wide geographical distribution, immunocompromised populations, and children. Active-comparator clinical trials and post-marketing studies demonstrate favorable reactogenicity profiles of Matrix-M-adjuvanted vaccines versus licensed vaccines for the same diseases, particularly, lower reactogenicity rates post-NUVAXOVID versus mRNA COVID-19 vaccination. Research is ongoing to better characterize Matrix-M immune-stimulating mechanisms, continue technology improvements, and identify new applications to enhance vaccines and therapeutics.

Background: We conducted a multicenter test-negative study to estimate vaccine effectiveness (VE) against medically attended, laboratory-confirmed influenza in primary care, Europe, 2024/25.

Research design and methods: Specimens were collected from patients with acute respiratory infection. All or a random sample of viruses were sequenced. VE was (1-odds ratio) × 100, adjusted for confounders.

Results: We included 7275 cases and 17,516 controls (weeks 40-2024-18-2025). The overall VE was 46% (95% CI: 40-52), lowest in adults ≥65 years at 28% (95% CI: 12-42). VE against influenza A(H1N1)pdm09 was 30% (95% CI: 19-40); ranging 16-34% by age and vaccination target group. Most (88%) circulating clades were 5a.2a, distinct from the vaccine clade. VE was 28% (95% CI: 7-45) against 5a.2a (C.1.9), and 6% (95% CI: -62-45) against the vaccine-matched clade 5a.2a.1 (D). VE against influenza A(H3N2) was 38% (95% CI: 26-49); ranging 20-66% by age and target group. Circulating viruses belonged to the vaccine clade 2a.3a.1, with 88% subclade (J.2). VE against influenza B was 76% (95% CI: 69-81); ranging 70-80% by age and target group; all viruses belonged to the vaccine clade V1A.3a.2, with diverse subclades.

Conclusions: Influenza vaccination protected approximately one in two vaccinated individuals against medically attended infection in primary care in Europe, 2024/25, varying by (sub)type and age.

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.