Expert Review of Vaccines最新文献

Background: Using adapted COVID-19 vaccines targeting current variants in circulation is necessary for addressing the dynamic evolution of the SARS-CoV-2 virus and protecting against emerging variants.

Research design and methods: Using a previously published, combined Markov-decision tree model adapted for Costa Rica, this study estimated the outcomes of different vaccination strategies with BNT162b2 COVID-19 mRNA vaccine, targeting various age and risk groups. The model used age-specific epidemiology, clinical, cost, and quality-of-life inputs derived from the published literature and national surveillance data. Scenario analyses that implemented variation in COVID-19 incidence and sensitivity analyses were both conducted to assess uncertainty.

Results: Compared to no adapted vaccine, the vaccination strategy in older adults aged ≥65 years and the high-risk population aged 18-64 years was estimated to prevent 3704 symptomatic cases, 3670 outpatient cases, 35 hospitalizations, 102 lost quality-adjusted life-years (QALYs), and one death, translating to total direct and societal cost savings of US$9,465,324 and US$10,569,883, respectively. Expanding vaccination to adults aged ≥60 years and high-risk individuals aged 18-59 years further increased benefits.

Conclusions: Implementing an adapted COVID-19 vaccine strategy for high-risk and older adults in Costa Rica is expected to be cost-saving, with broader age group eligibility yielding even greater benefits.

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: The aging population increases healthcare challenges, especially in preventing infectious diseases. Respiratory syncytial virus (RSV), historically associated with pediatric illness, is now recognized as a significant cause of severe disease and mortality in older adults. Despite scientific advances, including new RSV vaccines, adult immunization policies across Europe remain fragmented and underdeveloped.

Research design and methods: This study, promoted by the World Federation of Public Health Associations (WFPHA), assessed RSV surveillance, vaccination strategies, and capacity-building effort in eight European countries (Bulgaria, Finland, Germany, Italy, Norway, Portugal, Spain, and Serbia). A structured questionnaire, informed by a preliminary literature review, was administered to a panel of 19 experts, with a 79% (15/19) response rate.

Results: Findings revealed marked heterogeneity and persistent gaps across countries, including fragmented RSV surveillance, limited or missing vaccine recommendations for older adults, lack of age-specific monitoring, and insufficient training and communication initiatives for healthcare providers and the public.

Conclusion: To address these issues, the expert panel proposed policy recommendations to improve surveillance, ensure equitable vaccine access, and enhance professional training and awareness, providing a roadmap for stronger, prevention-focused healthcare across Europe.

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.

Background: This study aimed to update the incidence and mortality of pneumococcal diseases and to evaluate the population-level trends in pneumococcal diseases incidence in Thailand, following PCV13 licensure and during the COVID-19 pandemic, in order to generate evidence supporting its inclusion in the National Immunization Program (NIP).

Research design and methods: We conducted a quasi-experimental interrupted time-series analysis using sentinel hospital surveillance data from adults aged ≥ 18 years hospitalized with pneumococcal disease in Thailand between 2010 and 2024. Surveillance comprised retrospective passive data collection (2010-July 2023) and prospective active surveillance (August 2023-July 2024), applying consistent case definitions and outcome ascertainment methods throughout. Four epidemiologic periods were predefined based on PCV13 licensure and key phases of the COVID-19 pandemic.

Results: Among 2069 hospitalized adults, 61.0% were aged ≥ 65 years. Non-invasive pneumococcal pneumonia (NIPP) accounted for 72.8% of cases, while invasive pneumococcal disease (IPD) comprised 27.2%, with a rising trend over time. The overall in-hospital fatality rate was 23.4%, significantly higher in IPD (31.7%) than in NIPP (20.4%, p < 0.001). The incidence of both IPD and NIPP nearly tripled over the study period. IPD increased from 1.43 to 4.05 per 100,000 population, while NIPP rose from 3.23 to 10.92 per 100,000 population, with a marked increase observed during the recent COVID-19 pandemic period. An increasing trend in macrolide resistance was observed in IPD and NIPP, particularly during the COVID-19 pandemic. Serotype analysis showed that PCV13 covered 79% of all isolates, PCV15 covered up to 79-81%, and PCV20 offered the broadest coverage (up to 95%), particularly for IPD.

Conclusions: The burden of pneumococcal diseases in Thailand remains substantial, especially during the recent COVID-19 pandemic. The majority of disease-causing serotypes remained vaccine-type strains. Given that PCV13 or PCV15 inclusion in the Thai adult NIP should be prioritized to reduce the disease burden and antimicrobial-resistant pneumococcal infections.

Clinical trial registration: This study was registered with the Thai Clinical Trial Registry (TCTR20230816007).

Background: The role of Fc-mediated immune responses in protecting against herpes zoster remains poorly understood. This study aimed to evaluate the Fc-mediated immune responses of anti-VZV glycoprotein E antibodies induced by two licensed varicella-zoster virus vaccines.

Research design and methods: We established two cohorts, each consisting of 48 healthy participants aged 50 or above, who received either the ZVL or RZV. Serum samples were measured to evaluate the Fc-mediated immune responses for antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and antibody-dependent neutrophil phagocytosis (ADNP) against VZV-gE. The correlations between Fc-mediated functions and the IgG levels were also analyzed.

Results: Both ZVL and RZV significantly induced Fc effector function responses against HZ in participants after vaccination. Compared with ZVL recipients, RZV recipients exhibited significantly higher increase-fold of ADCC responses (ZVL: 1.93-fold; RZV: 8.44-fold, p < 0.001). In each vaccine group, the younger recipients showed higher ADCC responses than did the older (ZVL: 2.17-fold vs. 1.45-fold, p = 0.0136; RZV: 8.93-fold vs. 7.43-fold, p = 0.0677). Similar patterns were observed for ADCP and ADNP responses.

Conclusion: RZV induced superior Fc effector functions of VZV-gE antibodies compared to ZVL did. Older adults exhibited weaker Fc-mediated responses compared to younger adults following vaccination.

Background: In the context of China's aging population and low influenza vaccine coverage, this study applied the Behavioral and Social Drivers (BeSD) framework to investigate the willingness and determinants of influenza vaccination among adults aged ≥60 years in Chongqing.

Research design and methods: We designed a cross-sectional survey targeting the community population and collected data on willingness toward demographic and influenza vaccination through questionnaires. Descriptive analysis, logistic regression analyses were used to summarize the data and identify the possible factors of vaccination willingness.

Results: Among 1617 participants, 46.9% (95%CI: 44.5-49.3) expressed willingness to receive influenza vaccines. Individuals aged ≥80 years (aOR = 1.51, 95%CI: 1.10-2.08) and having basic medical insurance for urban employees (aOR = 2.21, 95%CI: 1.69-2.90) were more likely to receive influenza vaccination. Participants who lived in rural areas (aOR = 0.38, 95%CI: 0.39-0.50) were more likely to experience vaccine hesitancy. Concerning the BeSD framework, concern of worsening health condition (74.43%) and concern of disrupted daily life (69.76%) were the primary and secondary concerns, whereas perceived high vaccine cost (54.95%) was identified as a major reason for hesitancy.

Conclusions: This study further highlighted that psychological determinants, thinking and feeling are the most influential of vaccine acceptance and hesitancy.

Background: Respiratory syncytial virus (RSV) can cause substantial morbidity and mortality in adults aged 50-59 years at increased risk of severe RSV disease due to specific underlying conditions (i.e. '50-59 years at-increased-risk [AIR] population'), and in older adults aged ≥60 years (i.e. '≥60 years population').

Research design and methods: A static multi-cohort Markov model estimated cost-effectiveness of adjuvanted RSVPreF3 vaccination versus no vaccination among the 50-59 years AIR and ≥60 years populations in Japan, over a five-year time horizon from a healthcare payer perspective. Japan-specific RSV epidemiology and healthcare resource utilization parameters were used; vaccine efficacy was derived from the phase 3 AReSVi-006 trial (NCT04886596).

Results: Adjuvanted RSVPreF3 vaccination was cost-effective: in the 50-59 years AIR population, 49,280 RSV cases were prevented and 4333 quality-adjusted life years (QALYs) gained, at an incremental cost-effectiveness ratio (ICER) of Japanese yen (JPY) 2,770,558/QALY; in the ≥60 years population, 2,111,080 RSV cases were prevented and 205,543 QALYs gained, at an ICER of JPY 2,613,241/QALY. Vaccination was more cost-effective when including productivity losses from RSV-ARI. Scenario and sensitivity analyses results were robust.

Conclusions: RSV vaccination may provide substantial health benefits and be a cost-effective intervention to reduce RSV burden in adults in Japan.

Introduction: Pneumococcal disease leads to high morbidity and mortality, particularly in older adults and immunocompromised individuals. Many pneumococcal conjugated vaccines (PCVs) have become available. However, the immunogenicity, efficacy, and effectiveness data of these vaccines in older adults and immunocompromised individuals are limited.

Areas covered: This review aims to critically examine the immune responses, immune correlations, efficacy, real-world effectiveness, and cost-effectiveness of pneumococcal conjugated vaccines (PCVs) in older adults and immunocompromised individuals.

Expert opinion: A single dose of 20-valent or 21-valent PCV is recommended for older adults and immunocompromised individuals. Immune correlates of protection vary by serotype and race. An IgG level of 0.35 µg/mL is associated with protection, though this threshold is serotype-dependent. Opsonophagocytic assays, with a threshold of 1:8, remain the most reliable functional correlate of protection against invasive pneumococcal disease. Standardized immunological assays are essential for evaluating immune responses. High-valent PCVs have shown noninferior immunogenicity compared to PCV13, though geometric mean fold rises (GMFRs) for shared serotypes are slightly lower. Real-world effectiveness data are still needed, particularly in regions with differing serotype prevalence. Serotype surveillance is crucial when introducing PCV programs. Due to the high cost of higher-valent PCVs, many countries continue using PCV13 or PCV15 followed by PPSV23 for high-risk groups.

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.