Expert Review of Vaccines最新文献

Introduction: Current vaccines vary widely in both their efficacy against infection and disease, and the durability of the efficacy. Some vaccines provide practically lifelong protection with a single dose, while others provide only limited protection following annual boosters. What variables make vaccine-induced immune responses last? Can breakthroughs in these factors and technologies help us produce vaccines with better protection and fewer doses? The durability of vaccine-induced protection is now a hot area in vaccinology research, especially after COVID-19 vaccines lost their luster. It has fueled discussion on the eventual utility of existing vaccines to society and bolstered the anti-vaxxer camp. To sustain public trust in vaccines, lasting vaccines must be developed.

Areas covered: This review summarizes licensed vaccines' protection. It analyses immunological principles and vaccine and vaccinee parameters that determine longevity of antibodies. The review concludes with challenges and the way forward to improve vaccine durability.

Expert opinion: Despite enormous advances, we still lack essential markers and reliable correlates of lasting protection. Most research has focused on humoral immune responses, but we must also focus on innate, mucosal, and cellular responses - their assessment, correlates, determinants, and novel adjuvants. Suitable vaccine designs and platforms for durable immunity must be found.

Background: Cell-based quadrivalent inactivated influenza vaccines (IIV4c) avoid egg-adaptive mutations found in egg-based production, improving vaccine effectiveness (VE). Studies demonstrate improved VE for IIV4c relative to egg-based quadrivalent inactivated influenza vaccines (IIV4).

Research design and methods: We built on a static compartmental model developed by the CDC to estimate the influenza burden in persons 0-64 years that would be additionally averted by vaccination with IIV4c vs. IIV4. Model inputs were based on published data from 2017-2018, 2018-2019, and 2019-2020 Northern Hemisphere influenza seasons for the US.

Results: Over 3 influenza seasons, relative to IIV4, IIV4c would avert 31-39% more symptomatic cases, 29-40% more outpatient visits, 29-38% more hospitalizations and ICU admissions, and 34-49% more deaths vs. IIV4. In a deterministic sensitivity analysis, the main drivers were the relative VE of IIV4c vs. IIV4 in the 2017-2018 season and influenza burden estimates for the 2018-2019 and 2019-2020 seasons. Probabilistic sensitivity analysis showed that the interquartile range of symptomatic cases was ± 13% of baseline in 2017-2018, ±8% in 2018-2019, and ± 7% in 2019-2020.

Conclusions: IIV4c prevented significantly more symptomatic cases, outpatient visits, hospitalizations, and deaths than IIV4 in persons aged 0-64 years over 3 influenza seasons.

Background: The Japanese National Immunization Program currently includes the pediatric 13 valent pneumococcal conjugate vaccine (PCV13) to prevent pneumococcal infections. We aimed to evaluate the cost-effectiveness of 20-valent PCV (PCV20) as a pediatric vaccine versus PCV13.

Methods: A decision-analytic Markov model was used to estimate expected costs, quality-adjusted life-years (QALYs), and prevented cases and deaths caused by invasive pneumococcal disease, pneumonia, and acute otitis media over a ten-year time horizon from the societal and healthcare payer perspectives.

Results: PCV20 was dominant, i.e. less costly and more effective, over PCV13 (gained 294,599 QALYs and reduced Japanese yen [JPY] 352.6 billion [2.6 billion United States dollars, USD] from the societal perspective and JPY 178.9 billion [USD 1.4 billion] from the payer perspective). Sensitivity and scenario analyses validated the robustness of the base scenario results. When comparing PCV20 with PCV13, the threshold analysis revealed an incremental cost-effectiveness ratio that was within the threshold value (JPY 5 million/QALY) at a maximum acquisition cost of JPY 74,033 [USD 563] (societal perspective) and JPY 67,758 [USD 515] (payer perspective).

Conclusions: As a pediatric vaccine, PCV20 was dominant over PCV13 regardless of the study perspective.

Introduction: Whooping cough, also known as pertussis, remains a significant challenge as a vaccine-preventable disease worldwide. Since the switch from the whole-cell Pertussis (wP) vaccine to the acellular Pertussis vaccine (aP), cases of whooping cough have increased in countries using the aP vaccine. Understanding the immune system's response to pertussis vaccines and infection is crucial for improving current vaccine efficacy.

Areas covered: This review of the literature using PubMed records offers an overview of the qualitative differences in antibody and T cell responses to B. pertussis (BP) in vaccination and infection, and their potential association with decreased efficacy of the aP vaccine in preventing infection and subclinical colonization. We further discuss how asymptomatic infections and carriage are widespread among vaccinated human populations, and explore methodologies that can be employed for their detection, to better understand their impact on adaptive immune responses and identify key features necessary for protection against the disease.

Expert opinion: An underappreciated human BP reservoir, stemming from the decreased capacity of the aP vaccine to prevent subclinical infection, offers an alternative explanation for the increased incidence of clinical disease and recurrent outbreaks.

Introduction: Invasive meningococcal disease (IMD) is potentially fatal and associated with severe sequelae among survivors. It is preventable by several vaccines, including meningococcal vaccines targeting the most common disease-causing serogroups (A, B, C, W, Y). The meningococcal ACWY tetanus toxoid conjugate vaccine (MenACWY-TT [Nimenrix]) is indicated from 6 weeks of age in the European Union and >50 additional countries.

Areas covered: Using PubMed, Google Scholar, ClinicalTrials.gov and ad hoc searches for publications to June 2023, we review evidence of antibody persistence for up to 10 years after primary vaccination and up to 6 years after MenACWY-TT revaccination. We also review global MenACWY revaccination recommendations and real-world impact of vaccination policies, focusing on how these data can be considered alongside antibody persistence data to inform future IMD prevention strategies.

Expert opinion: Based on clear evidence that immunogenicity data (demonstrated antibody titers above established correlates of protection) are correlated with real-world effectiveness, long-term persistence of antibodies after MenACWY-TT vaccination suggests continuing protection against IMD. Optimal timing of primary and subsequent vaccinations is critical to maximize direct and indirect protection. Recommending bodies should carefully consider factors such as age at vaccination and long-term immune responses associated with the specific vaccine being used.