Expert Review of Vaccines最新文献

Introduction: Pertussis poses a significant threat to infants under six months due to their immature immune systems, limited maternal antibody protection, and constraints in the vaccination schedule. Despite vaccination efforts, this group remains highly susceptible to severe complications. Addressing these challenges is crucial for improving the health outcomes of infants in China.

Areas covered: This review examines the primary challenges in preventing pertussis infections among infants under six months in China, focusing on factors such as underdeveloped immune system and inadequate maternal antibody protection. It analyzes limitations in current vaccination strategies and the impact of socio-cultural factors, healthcare resource distribution, and surveillance inadequacies. A comprehensive literature search was conducted to identify potential solutions, including enhancing maternal immunization, adjusting early vaccination strategies, increasing vaccine coverage, and developing new vaccines. The review synthesizes current research findings and data to provide a detailed overview of these issues.

Expert opinion: Infants under six months are particularly vulnerable to pertussis. Early and effective prevention strategies, such as enhanced maternal immunization and adjusted vaccination schedules, are needed. Increasing vaccine coverage and developing safer, more immunogenic vaccines are essential. Policymakers should prioritize these measures to reduce pertussis incidence and complications among infants in China.

Background: Respiratory syncytial virus (RSV) is an important cause of severe respiratory illness in older adults and adults with certain health conditions. Adjuvanted RSVPreF3 and non-adjuvanted RSVpreF vaccines were approved in 2023 for use in adults aged ≥60 years in the United States (US). This study explored the impact of RSV vaccination during the first season of vaccine availability.

Research design and methods: A Markov model was adapted to compare RSV-related outcomes in adults aged ≥60 years with or without RSV vaccination. Analyses were based on real-world RSV vaccination uptake and effectiveness in the 2023-2024 season. Scenario analyses assumed the same higher uptake as for influenza vaccines.

Results: Over 1 year, real-world RSV vaccinations were estimated to avert 18,326 RSV-related emergency department (ED) visits, 23,630 hospitalizations, and 1,930 deaths versus no vaccination. Assuming the same uptake as for influenza vaccines resulted in considerable additional RSV disease burden averted (avoiding a total of 65,740 RSV-related ED visits, 84,551 hospitalizations, and 6,838 deaths over 1 year vs. no vaccination).

Conclusions: Findings suggest that real-world RSV vaccinations have substantially reduced RSV disease burden in the US. Increasing RSV vaccination uptake among eligible adults aged ≥60 years could provide additional public health benefits.

Introduction: Varicella-zoster virus (VZV) is a highly contagious virus that manifests as varicella (chickenpox) as primary infection and reactivates as herpes zoster (HZ, shingles), with the potential for severe complications. Vaccines against varicella and HZ are available and highly effective, but recommendations vary between countries.

Areas covered: This qualitative review discusses the literature regarding (i) the burden of varicella and HZ; (ii) current approaches to vaccination against VZV-related diseases and reasons why varicella and HZ vaccination may not have been widely implemented, and (iii) real-world evidence and trends from countries with vaccination program experience.

Expert opinion: Varicella and HZ pose significant burdens. The availability of effective vaccines with established safety profiles means that prevention of both manifestations of VZV disease is now largely possible. Reasons why National Immunization Technical Advisory Groups may not recommend varicella and HZ vaccination programs include cost-effectiveness, considerations relating to the interplay of both diseases, and low awareness of the true disease burden. Nevertheless, real-world evidence from countries with existing vaccination programs is demonstrating positive impacts of vaccination on disease incidence and cost. Including both varicella and HZ vaccines in National Immunization Programs can be an effective life-course strategy to tackle the burden of VZV-related diseases.

Introduction: The World Health Organisation (WHO) introduced the Expanded Programme on Immunisation (EPI) in 1974 to reduce morbidity and mortality from a range of vaccine-preventable infectious diseases including pertussis. However, almost 50 years later pertussis infection continues to be a public-health concern in high- and low-and-middle-income countries.

Areas covered: We review: the clinical heterogeneity of disease in an immunized population and the current estimates of global disease burden; the vaccine-types currently used to prevent pertussis infection and the evidence behind the current schedules of immunization recommended by the WHO; the current understanding of the immune responses relating to protection from disease and colonization; the regional differences in routinely used schedules of immunization.

Expert opinion: The current heterogeneity of schedules and vaccines reflects uncertainty about the best strategies for long-term control of pertussis infection. Whole cell pertussis vaccines are associated with sustained population control of infection but are reactogenic; acellular pertussis vaccines are less reactogenic but do not appear to give sustained protection against transmission. Continuing to develop and apply emerging insights into the nature of the immune responses needed to provide robust protection against pertussis may enable the development of novel vaccines and optimal schedules of immunization.

Background: The paper provides a novel perspective beyond existing theoretical frameworks by integrating the COM-B model with discrete choice experiments (DCEs) to quantify parental decision-making dynamics for adolescent HPV vaccination.

Research design and methods: Two cross-sectional surveys were conducted in Wuxi, China, before and after the introduction of free domestic bivalent vaccines. Multinomial logistic regression identified COM-B predictors of vaccination intention, whereas DCEs quantified parental preferences. Latent class analysis (LCA) linked preference heterogeneity to COM-B domains with policy simulations comparing 20 vaccination scenarios.

Results: Health benefit perception (motivation), financial/temporal self-efficacy (motivation), and social influence (opportunity) are key predictors. Generally, parents prioritized HPV vaccines with low cost, high efficacy, and low side effect risks, while hesitant and refusing parents showed less concern with appointment difficulties but preference for imported producers. Five distinct HPV vaccination preference groups are identified: domestic-affordable, cost-sensitive, efficacy-focused, safety-oriented, and accessibility-driven. Hesitant and refusing parents were representative in cost-sensitive and accessibility-driven, which were sensitive in simulated incentives or convenience-enhancing scenarios. Free domestic 2-valent vaccine maintained its dominance in choice probability across simulated scenarios, except for the National Immunization Program.

Conclusions: Findings support stratified interventions targeting motivation (education, persuasion) and opportunity (cost subsidies, accessibility) based on the free domestic 2-valent vaccine policy.

Introduction: To address the cervical cancer burden globally, the World Health Organization and European Union released strategies to facilitate HPV-related cancers prevention, including cervical cancer elimination. This research assessed European country level readiness to achieve cervical cancer elimination by adhering to such strategies.

Areas covered: Readiness for cervical cancer elimination was assessed across a range of guiding questions relevant to three defined key domains: vaccination, screening, and treatment, each with two sub-domains focusing on decision making and implementation efforts. Publicly available data sources were used to inform the scoring across domains, to tier countries into either high, moderate-high, moderate-low, and low readiness archetypes.Key parameters identified associated with the high readiness archetype were high vaccination coverage rates (>70%), availability of gender neutral and catch-up vaccination, school-based vaccination availability, organized screening programs, use of HPV DNA primary screening tests, and data surveillance.

Expert opinion: Our analysis highlights significant variability in decision making and implementation of vaccination, screening, and treatment programmes across Europe. Country scores expose the need for a multifaceted approach to achieve cervical cancer elimination in Europe, encompassing solid decision making commitments, implementation of these commitments, and the ability to collect, surveil, and apply the data use accurately.

Background: The development of bivalent or multivalent vaccines offers a promising strategy for combating SARS-CoV-2 mutations.

Research design and methods: In this phase 2 trial, conducted from 1 December 2021, to 25 July 2023, 392 unvaccinated adults aged ≥18 years were randomized to receive a primary series of two doses and a booster dose of SCTV01C, a bivalent protein SARS-CoV-2 vaccine.

Results: Geometric mean titers (GMTs) of neutralizing antibodies (nAb) against live Alpha, Beta, Delta, and Omicron showed 85.4-, 100.0-, 32.1-, and 9.8-fold increase from baseline on 28 days, and 49.4-, 55.3-, 5.7-fold increase against live Alpha, Beta, and Omicron on 90 days after primary series. At Day 28 and Day 90 following the booster dose, GMTs of nAb against Beta, BA.2 and BA.5 variants showed 12.1- and 8.8-, 13.8- and 7.1-, 18.7-, and 11.9-fold of increase from baseline, respectively. Reactogenicity was generally mild, with one adverse event of special interest (AESI) and 9 ≥Grade 3 treatment-related adverse events (TRAEs); all recovered within 3 days.

Conclusions: SCTV01C, when administered as both a primary series and a booster vaccination, exhibited encouraging sustained immunogenicity against both antigen-matched and antigen-mismatched variants, with no significant safety concerns.

Clinical trial registration: www.clinicaltrials.gov identifier is NCT05148091.

Introduction: Despite extensive efforts, global influenza vaccination rates remain suboptimal, particularly among high-risk populations.

Research design and methods: We conducted a comprehensive literature search up to April 2023. Experimental studies assessing the effectiveness of interventions on influenza vaccination uptake were included, expressed as risk ratios (RR) with 95% confidence intervals (CI). Random-effects meta-analysis models were utilized for pooled estimates, with heterogeneity assessed through I². Subgroup analyses and meta-regressions were performed.

Results: This meta-analysis includes 180 studies involving 2,390,119 participants and comprehensively evaluates the effectiveness of recipient-, provider-, health system-based, and multitarget interventions. Overall, interventions significantly increased vaccination rates, with a pooled RR of 1.26 (95% CI, 1.21 to 1.32). Notably, provider-based interventions were more effective for healthcare workers (RR = 1.56; 95% CI, 1.46 to 1.66), whereas recipient-based interventions were more efficacious for pregnant women (RR = 1.42; 95% CI, 1.09 to 1.85). Multitarget strategies were the most effective among older adults (RR = 2.10; 95% CI, 1.61 to 2.72) and population under age of 18 (RR = 1.53; 95% CI, 1.23 to 1.90).

Conclusions: These findings provide critical insights for optimizing public health strategies, underscoring the need for innovative and tailored approaches to enhance global vaccination uptake.

Background: Live-attenuated vaccines (LAVs) are typically contraindicated for immunocompromised patients and pregnant women, although the potential benefits of vaccination with LAV in these populations should not be overlooked. This systematic literature review was conducted to evaluate the safety of LAVs in immunocompromised patients and pregnant women.

Research design and methods: The searches were conducted across PubMed, Embase, and Cochrane databases. We included studies reporting on safety outcomes of LAV use in immunocompromised patients and pregnant women. A narrative synthesis was employed to present the primary findings.

Results: A total of 96 studies were included, reporting outcomes on 18 LAVs, mostly for varicella-zoster, measles-mumps-rubella, and influenza vaccines. Comparative studies revealed minor differences in adverse events (AEs) between immunocompromised LAV recipients and placebo recipients, and between immunocompromised and healthy vaccinated individuals. Severe AEs and fatalities were infrequent, primarily noted in oncology patients in case studies. Twelve studies addressed LAV safety in pregnant women, with no instances of vertical transmission reported, and no conclusive link found between LAVs and serious AEs.

Conclusions: LAVs appeared generally safe and well-tolerated for immunocompromised patients and pregnant women. However, evidence is still limited, and more research is needed to address data gaps and support evidence-based decision-making.