Expert Review of Vaccines最新文献

Introduction: Traditional live-attenuated or inactivated vaccines have limitations, including risks associated with uncontrolled replication, reduced immunogenicity, or production complexities. To address these issues, alternative platforms such as virus-like particles (VLPs) have been developed.

Areas covered: VLPs are self-assembling structures composed of viral proteins that mimic native viruses but are noninfectious. This review provides an overview of their structure, design and manufacture that make them an attractive platform for vaccine development. We then discuss the clinical development of some recently approved VLP vaccines and those widely used in immunization programs, summarizing the clinical trial data that underpins their efficacy and safety profiles. Additionally, we explore VLP vaccines in late-stage clinical development for respiratory syncytial virus and human metapneumovirus.

Expert opinion: VLPs are a versatile and promising platform for vaccine development. Their ability to mimic native viruses while eliminating the risks associated with live vaccines positions them as an attractive platform for vaccine design. Currently approved VLP vaccines demonstrate that they can provide effective protection against a wide range of diseases. Advances in VLP design and production are likely to lead to highly effective vaccines, significantly contributing to global immunization efforts.

Introduction: Non-survey-based data sources (e.g. electronic health records, administrative claims) have been used to estimate vaccination coverage among US adults. However, these data sources were not collected for research or surveillance purposes and may have substantial limitations. The objectives of this narrative review were to: 1) identify published studies that used non-survey-based data sources to estimate adult vaccination coverage for one or more routinely recommended vaccines; and 2) summarize the strengths and limitations of these data sources for coverage assessments.

Areas covered: Thirty-four publications derived from 9 data sources were reviewed: 16 publications were in a general population (i.e. defined by age), 12 were among pregnant women, and 6 were among individuals with chronic health conditions. While several data sources used continuous health insurance enrollment to define the study population, doing so limited generalizability to stably insured populations. Methods for obtaining race and ethnicity data were complex and potentially subject to bias. None of the reviewed studies presented any formal assessment of vaccine data validity.

Expert opinion: While multiple non-survey-based data sources have been used to assess adult vaccination coverage in the United States, important limitations exist, including related to generalizability, data validity, and risk of bias.

Introduction: The World Health Organization has recommended two pre-erythrocytic malaria vaccines targeting Plasmodium falciparum. However, there is currently no vaccine available for Plasmodium vivax, the second leading cause of malaria. To eliminate malaria, transmission-blocking vaccines (TBVs) that can prevent infection of mosquitoes from humans would be helpful.

Areas covered: This review summarizes the identification of targets, progress, and prospects in developing malaria TBVs. We searched PubMed for studies published up to 11 April 2025, using the terms ['Pfs25' OR 'Pfs230' OR 'Pfs48/45' OR 'Pvs25' OR 'Pvs230' OR 'Pvs48/45' OR 'AnAPN1'] AND ['malaria transmission-blocking vaccine'].

Expert opinion: After over 30 years of research and development, Pfs230 for P. falciparum and Pvs25 for P. vivax are the most advanced candidates for transmission-blocking vaccines.

Background: The ongoing emergence of SARS-CoV-2 variants has raised concerns about the breadth of the immune response provided by existing vaccines.

Research design and methods: In this study, participants aged 18-75 years with no prior COVID-19 infection or vaccination history were enrolled to receive the CoronaVac vaccine. The interval between the first and second vaccine doses was 28 days, while the third dose was given 6 months after the second.

Results: Between February 1 to 15 February 2022, we recruited 40 eligible participants who had not received any COVID-19 vaccination and had no prior COVID-19 infection. After the third dose, neutralizing antibody levels significantly increased against the ancestral strain and certain Omicron variants (BA.1, BA.4/5, BF.7). Compared to levels observed 28 days post-second dose, neutralizing antibody levels rose further 28 days after the third dose, with the GMFI against the ancestral strain at 1.69 (95% CI: 1.27, 2.20). Among other variants, the GMFI against Omicron variants (BA.1, BA.4/5, BF.7) exceeded that for Beta and Delta, with the highest GMFI recorded for the BA.4/5 variant at 4.97 (95% CI: 3.08, 8.05).

Conclusions: The necessity of the third booster dose lies in its ability to enhance the breadth of the immune response.

Introduction: Comparative effectiveness data of COVID-19 vaccines remain limited. We conducted a systematic review and network meta-analysis (NMA) feasibility assessment of effectiveness studies of Omicron-adapted COVID-19 vaccines.

Research design and methods: Searches in MEDLINE and Embase up to February 2025 identified studies comparing the effectiveness of Omicron-adapted COVID-19 vaccines, either directly or against no recent vaccine. Two investigators independently selected articles reporting adjusted vaccine effectiveness (VE). A feasibility assessment determined the appropriateness of a common comparator and evaluated effect modifiers (EMs). Data extraction and risk-of-bias assessment were performed by one investigator and validated by a second investigator. Bayesian NMAs using random-effects models were performed for base-case analyses, data permitting.

Results: The review identified 25 studies for Omicron-adapted COVID-19 vaccines: 16 for XBB formulations, eight of which were included in NMAs, all for mRNA formulations, representing 29.9 million participants. BNT162b2 had the largest evidence base. Comparisons between XBB.1.5-adapted BNT162b2 (Comirnaty) and mRNA-1273 (Spikevax) found that both vaccines are effective and comparable against XBB-related hospitalizations, infections, and medically attended visits in adults Among elderly, the estimated effectiveness against XBB-related hospitalizations favored BNT162b2.

Conclusions: Findings of this NMA of observational studies support the effectiveness of XBB.1.5-adapted mRNA vaccines. Limitations included assumptions on EMs and sparse evidence networks.

Introduction: Immunization Information Systems (IISs) are essential public health tools, supporting the management and analysis of vaccination data to aid clinical and strategic decision-making.

Methods: Following PRISMA guidelines, this systematic review investigated global state and operational characteristics of IISs. A comprehensive search across multiple databases up to 6^th of June 2023, identified 2,612 articles, with 238 included.

Results: A significant increase in IIS research was observed in recent years, with a strong preference (84.5%) for electronic immunization registers (EIRs). Notably, 36% of IISs operate at the national level, and 47.7% meet the U.S. CDC definition, 17.0% are interoperable with personal health records, and 11.7% provide direct access to vaccination data for vaccinees or their guardians. Other key features include automated reminder systems for recipients and providers (12.1%), near real-time or real-time data entry (11.0%), the inclusion of demographic and socioeconomic data (16.7%), and the capacity to document vaccine refusal or hesitancy (10.2%).

Conclusions: IISs contribute to improving population-level surveillance of vaccine-preventable diseases. Persistent limitations related to data standardization, interoperability, and cost-effectiveness evaluation must be addressed. Strengthening these aspects is crucial to fully harness the potential of IISs in various healthcare settings, where enhanced vaccination tracking and targeting are most urgently needed.

Background: Clinical trials have compared new pneumococcal conjugative vaccines (PCVs; PCV15 and PCV20) to an established PCV (PCV13) in a routine 2 + 1 schedule. This study performed an indirect comparison of PCV15 vs. PCV20 immune responses in healthy infants and toddlers.

Research design and methods: Pooled, matching-adjusted PCV15 trials were indirectly compared to the analogous PCV20 trial for IgG response rate difference (RRD) and geometric mean concentration ratio (GMR) at the post-primary series (PPS) and post-toddler dose (PTD) timepoints.

Results: At PPS, PCV15 was non-inferior for RRD and GMR as compared to PCV20 for all PCV13 serotypes. Moreover, PCV15 was superior to PCV20 for the RRDs of serotypes 1, 3, 4, 5, 6B, 9V, and 23F and GMRs of serotypes 3, 4, 5, 6B, 9V, and 23F at PPS. At PTD, RRDs were comparable for all PCV13 serotypes, except serotype 3, for which PCV15 was superior. PCV15 was superior for the GMRs of serotypes 3, 6B, and 23F, and comparable for the remaining serotypes at PTD. RRDs for serotypes 22F and 33F were non-inferior at both PPS and PTD.

Conclusion: In a 2 + 1 schedule, PCV15 demonstrates immunogenicity comparable or superior to PCV20 across PCV13 serotypes, especially for serotype 3.

Introduction: Recombinant Zoster Vaccine (RZV) is recommended for Herpes Zoster (HZ) prevention in high-risk patients over 18 years of age.

Research design and methods: This is a prospective population-based study conducted over a three-year period in a Southern Italian General Hospital. The study population was represented by RZV recipients with diverse chronic comorbidities. Adverse Events Following Immunization (AEFIs), baseline disease flares and post-vaccination HZ episodes were evaluated through sequential follow-ups conducted 7 days, 3 months, and 3-38 months post-vaccination, respectively.

Results: Study population included 787 RZV recipients, mostly affected by onco-hematological, cardiovascular and rheumatological disorders. The AEFIs reporting rate was 44.15%. The most frequent symptoms were injection site pain/itching (37.19%), asthenia/malaise (12.74%) and fever (10.30%). Three serious AEFIs with consistent causal association with vaccination were recorded (0.22%), all of which underwent full recovery. Sixteen patients (2.37%) experienced a baseline condition flare-up within 3 months (mean interval 33.88 ± 24.88 days). Multiple baseline disorders (OR:1.97; 95%CI:1.37-2.83; p-value < 0.001) and rheumatological conditions (OR:11.67; 95%CI:2.00-68.27; p-value < 0.01) increased flare risk, while male sex decreased it. Twenty-six vaccinees manifested HZ post-vaccination (cumulative incidence rate 5.05/100,000 person-days), with particularly increased incidence in patients with recurrent/severe HZ history (IRR:14.35; 95%CI:5.64-34.04; p-value < 0.001).

Conclusion: The study demonstrates RZV safety and HZ protection in vulnerable patients, consistently with available evidence.

Background: Vaccine hesitancy among healthcare workers (HCWs) is a global concern, needing reliable tools to measure HCW vaccine confidence. We adapted and validated the 10-item 'iPro-VC-Be' tool for the Nigerian context.

Research design and methods: We conducted a 3-step process. First, contextual adaptation using expert round-table discussions and cognitive interviews with HCWs in Oyo and Jigawa States (12/2023-05/2024). Second, translation and back-translation to Hausa, Igbo and Yoruba, including HCW group discussions (05/2024). Finally, testing validity in all languages, using a test-retest approach (06/2024-09/2024).

Results: Sixty-four participants contributed to adaptation, 25 researchers and 39 HCWs supported translations, 435 HCWs completed the first survey, and 263 completed the re-test. Of the 10 iPro-VC-Be items, 3 were unchanged, 6 had language edits, and 1 was replaced. The Cronbach's alpha indicated good internal reliability, and overall the intraclass correlation coefficient indicated moderate re-test reliability. Confirmatory factor analysis supported goodness of fit across multiple indices, but one negatively framed item performed poorly. Items assessing confidence in vaccines and trust in government were significantly associated with HCW vaccine uptake.

Conclusion: The adapted iPro-VC-Be was valid, however, we recommend using a shorter 6-item version for Nigeria that does not include items linked to immunization resources.