Expert Review of Vaccines最新文献

Introduction: The use of novel adjuvants in human vaccines continues to expand as their contribution to preventing disease in challenging populations and caused by complex pathogens is increasingly understood. AS01 is a family of liposome-based vaccine Adjuvant Systems containing two immunostimulants: 3-O-desacyl-4'-monophosphoryl lipid A and the saponin QS-21. AS01-containing vaccines have been approved and administered to millions of individuals worldwide.

Areas covered: Here, we report advances in our understanding of the mode of action of AS01 that contributed to the development of efficacious vaccines preventing disease due to malaria, herpes zoster, and respiratory syncytial virus. AS01 induces early innate immune activation that induces T cell-mediated and antibody-mediated responses with optimized functional characteristics and induction of immune memory. AS01-containing vaccines appear relatively impervious to baseline immune status translating into high efficacy across populations. Currently licensed AS01-containing vaccines have shown acceptable safety profiles in clinical trials and post-marketing settings.

Expert opinion: Initial expectations that adjuvantation with AS01 could support effective vaccine responses and contribute to disease control have been realized. Investigation of the utility of AS01 in vaccines to prevent other challenging diseases, such as tuberculosis, is ongoing, together with efforts to fully define its mechanisms of action in different vaccine settings.

Background: Updating vaccines is essential for combatting emerging coronavirus disease 2019 (COVID-19) variants. This study assessed the public health and economic impact of a booster dose of an adapted vaccine in the United Kingdom (UK).

Methods: A Markov-decision tree model estimated the outcomes of vaccination strategies targeting various age and risk groups in the UK. Age-specific data derived from published sources were used. The model estimated case numbers, deaths, hospitalizations, medical costs, and societal costs. Scenario analyses were conducted to explore uncertainty.

Results: Vaccination targeting individuals aged ≥ 65 years and the high-risk population aged 12-64 years was estimated to avert 701,549 symptomatic cases, 5,599 deaths, 18,086 hospitalizations, 56,326 post-COVID condition cases, and 38,263 lost quality-adjusted life years (QALYs), translating into direct and societal cost savings of £112,174,054 and £542,758,682, respectively. The estimated economically justifiable price at willingness-to-pay thresholds of £20,000 and £30,000 per QALY was £43 and £61, respectively, from the payer perspective and £64 and £82, respectively, from the societal perspective. Expanding to additional age groups improved the public health impact.

Conclusions: Targeting individuals aged ≥ 65 years and those aged 12-64 years at high risk yields public health gains, but expansion to additional age groups provides additional gains.

Background: New York State (NYS) reported a polio case (June 2022) and outbreak of imported type 2 circulating vaccine-derived poliovirus (cVDPV2) (last positive wastewater detection in February 2023), for which uncertainty remains about potential ongoing undetected transmission.

Research design and methods: Extending a prior deterministic model, we apply an established stochastic modeling approach to characterize the confidence about no circulation (CNC) of cVDPV2 as a function of time since the last detected signal of transmission (i.e. poliovirus positive acute flaccid myelitis case or wastewater sample).

Results: With the surveillance coverage for the NYS population majority and its focus on outbreak counties, modeling suggests a high CNC (95%) within 3-10 months of the last positive surveillance signal, depending on surveillance sensitivity and population mixing patterns. Uncertainty about surveillance sensitivity implies longer durations required to achieve higher CNC.

Conclusions: In populations that maintain high overall immunization coverage with inactivated poliovirus vaccine (IPV), rare polio cases may occur in un(der)-vaccinated individuals. Modeling demonstrates the unlikeliness of type 2 outbreaks reestablishing endemic transmission or resulting in large absolute numbers of paralytic cases. Achieving and maintaining high immunization coverage with IPV remains the most effective measure to prevent outbreaks and shorten the duration of imported poliovirus transmission.

Introduction: Technological innovations have been instrumental in advancing vaccine design and protective benefit. Improvements in the safety, tolerability, and efficacy/effectiveness profiles have profoundly reduced vaccine-preventable global disease morbidity and mortality. Here we present an original vaccine platform, the Multiple Antigen Presenting System (MAPS), that relies on high-affinity interactions between a biotinylated polysaccharide (PS) and rhizavidin-fused pathogen-specific proteins. MAPS allows for flexible combinations of various PS and protein components.

Areas covered: This narrative review summarizes the underlying principles of MAPS and describes its applications for vaccine design against bacterial and viral pathogens in non-clinical and clinical settings.

Expert opinion: The utilization of high-affinity non-covalent biotin-rhizavidin interactions in MAPS allows for combining multiple PS and disease-specific protein antigens in a single vaccine. The modular design enables a simplified exchange of vaccine components. Published studies indicate that MAPS technology may support enhanced immunogenic breadth (covering more serotypes, inducing B- and T-cell responses) beyond that which may be elicited via PS- or protein-based conjugate vaccines. Importantly, a more detailed characterization of MAPS-based candidate vaccines is warranted, especially in clinical studies. It is anticipated that MAPS-based vaccines could be adapted and leveraged across numerous diseases of global public health importance.

Background: Japanese encephalitis (JE) is a severe infectious disease of the central nervous system. Vaccination with Vero cell culture-derived vaccines may effectively reduce JE incidence.

Research design and methods: In this single-center, randomized, blinded, positive-controlled clinical trial in China involving 600 healthy infants aged 6-11 months, participants were divided into experimental and control groups administered JEV-PI and JEV-LI, respectively. Antibody titers were determined after 0- and 7-day immunization schedules. A booster dose followed 12 months later.

Results: After primary vaccination and before booster vaccination, the positive conversion rate, geometric mean titer (GMT), and geometric mean increase (GMI) of JEV-PI-neutralizing antibodies exceeded those of JEV-LI. After booster immunization, the GMT and GMI of JEV-PI were higher than those of JEV-LI. After primary immunization, the local, systemic, and overall adverse reactions were of grades 1 and 2, with a low incidence of grade 3. After booster immunization, these differences were mainly grades 1 and 2, with no differences between JEV-PI and JEV-LI.

Conclusion: JEV-PI is a promising vaccine as infants acquired long-lasting and highly neutralizing immune antibodies after inoculation with JEV-PI.

Trial registration: The trial was registered in the Chinese Clinical Trial Registry (https://www.chictr.org.cn/showproj.html?proj = 203130; registration number: ChiCTR2300074692; registration date: 14/08/2023).

Objectives: Annually in France, influenza results in over one million GP consultations, around 20,000 hospitalizations, and approximately 9,000 deaths. This study assesses the cost-effectiveness of cell-based quadrivalent influenza vaccine (QIVc) for those under 65, which enhances effectiveness avoiding egg-adaptation, compared to egg-based quadrivalent influenza vaccine (QIVe).

Methods: An age-structured susceptible-exposed-infected-recovered (SEIR) transmission model, calibrated to represent an average influenza season based on French data from 2011 to 2019, integrates a contact matrix estimating intergroup contact rates. Evaluating epidemiological, economic and utility outcomes, the model includes vaccine effectiveness and medical costs from the existing literature and French national data. Adjustments to quality of life due to infection and hospitalization are also included. Uncertainty is explored through scenario and sensitivity analyses.

Results: Compared to QIVe, QIVc significantly reduces healthcare utilization and mortality, preventing 49,946 GP consultations, 1,087 hospitalizations, and 231 deaths in France. Despite an initial investment of 7.6 million euros, QIVc achieves a net saving of 12 million euros in healthcare expenditures, making it a dominant cost-saving strategy. Probabilistic sensitivity analyses indicate dominance in 78% of 10,000 simulations.

Conclusions: Introducing cell-based influenza vaccines in the French immunization program prevents influenza cases, hospitalizations, death, while reducing costs versus egg-based influenza vaccines.

Introduction: Cancer vaccines stimulate the activation of specific humoral and cellular adaptive responses against cancer cells.Antibodies generated post vaccination can be isolated and further selected to develop highly specific and potent monoclonal antibodies (mAbs) against tumor-associated antigens.

Areas covered: This review describes different types of cancer vaccines, the process of the generation of the mAb NEO-201 from the Hollinshead cancer vaccine platform, the characterization of the antigen recognized by NEO-201, the ability of NEO-201 to bind and mediate the killing of cancer cells and immunosuppressive cells (gMDSCs and Tregs) through ADCC and CDC, NEO-201 preclinical and clinical toxicity and efficacy.

Expert opinion: To overcome the problem of poor clinical efficacy of cancer vaccines, due to the activity of immunosuppressive cells, cancer vaccines could be combined with other immunotherapeutics able to deplete immunosuppressive cells. Results from clinical trials, employing NEO-201 alone or in combination with pembrolizumab, showed that durable stabilization of disease after treatment was due to the ability of NEO-201 to target and reduce the percentage of circulating Tregs and gMDSCs.These findings provide compelling support to combine NEO-201 with cancer vaccines to reintegrate their ability to elicit a robust and durable immune adaptive response against cancer.

Introduction: Tick-borne encephalitis (TBE) is rapidly spreading to new areas in many parts of Europe. While vaccination remains the most effective method of protection against the disease, vaccine uptake is low in many endemic countries.

Areas covered: We conducted a literature search of the MEDLINE database to identify articles published from 2018 to 2023 that evaluated the immunogenicity and effectiveness of TBE vaccines, particularly Encepur, when booster doses were administered up to 10 years apart. We searched PubMed with the MeSH terms 'Encephalitis, Tick-Borne/prevention and control' and 'Vaccination' for articles published in the English language.

Expert opinion: Long-term immunogenicity data for Encepur and real-world data on vaccine effectiveness and breakthrough infections following the two European TBE vaccines, Encepur and FSME-Immun, have shown that extending the booster interval from 3-5 years to 10 years does not negatively impact protection against TBE, regardless of age. Such extension not only streamlines the vaccination schedules but may also increase vaccine uptake and compliance among those living in endemic regions.

Introduction: The epidemiology of invasive meningococcal disease (IMD), a rare but potentially fatal illness, is typically described as unpredictable and subject to sporadic outbreaks.

Areas covered: Meningococcal epidemiology and vaccine use during the last ~ 200 years are examined within the context of meningococcal characterization and classification to guide future IMD prevention efforts.

Expert opinion: Historical and contemporary data highlight the dynamic nature of meningococcal epidemiology, with continued emergence of hyperinvasive clones and affected regions. Recent shifts include global increases in serogroup W disease, meningococcal antimicrobial resistance (AMR), and meningococcal urethritis; additionally, unvaccinated populations have experienced disease resurgences following lifting of COVID-19 restrictions. Despite these changes, a close analysis of meningococcal epidemiology indicates consistent dominance of serogroups A, B, C, W, and Y and elevated IMD rates among infants and young children, adolescents/young adults, and older adults. Demonstrably effective vaccines against all 5 major disease-causing serogroups are available, and their prophylactic use represents a powerful weapon against IMD, including AMR. The World Health Organization's goal of defeating meningitis by the year 2030 demands broad protection against IMD, which in turn indicates an urgent need to expand meningococcal vaccination programs across major disease-causing serogroups and age-related risk groups.

Background: The study's objective was to examine national trends in patterns of under-vaccination in the United States.

Research design and methods: The National Immunization Survey-Child (NIS-Child) is an annual cross-sectional survey that collects provider-verified vaccination records from a large national probability sample of children. Records from the 2011-2021 NIS-Child were used to assess receipt of the combined 7-vaccine series by age 24 months. Based on prior work, patterns indicative of hesitancy included zero vaccines, not starting ≥1 series, and consistent vaccine-limiting. Patterns indicative of practical issues included starting all series but missing doses. Up-to-date (UTD) was defined as receiving all doses in the combined 7-vaccine series.

Results: The study population comprised 127,257 children. Over the observation period, patterns indicative of hesitancy significantly decreased (p-trend < 0.0001), patterns indicative of practical issues significantly decreased (p-trend < 0.0001), and UTD significantly increased (p-trend < 0.0001). In 2021, the weighted percentage in each category was as follows: probable hesitancy 6.3% (95% confidence interval [CI] 5.4%, 7.2%), probable practical issues 26.0% (95% CI 24.4%, 27.6%), and UTD 67.7% (95% CI 66.0%, 69.4%).

Conclusion: Over an 11-year period, vaccination coverage in the United States for the combined 7-vaccine series has improved, with patterns suggestive of practical issues or hesitancy declining.