The case for assessing the full value of new tuberculosis vaccines

The Full Value of Vaccine Assessments (FVVA): a framework for assessing and communicating the value of vaccines for investment and introduction decision-making

BACKGROUND

Several economic obstacles can deter the development and use of vaccines. This can lead to limited product options for some diseases, delays in new product development, and inequitable access to vaccines. Although seemingly distinct, these obstacles are actually interrelated and therefore need to be addressed through a single over-arching strategy encompassing all stakeholders.

METHODS

To help overcome these obstacles, we propose a new approach, the Full Value of Vaccines Assessments (FVVA) framework, to guide the assessment and communication of the value of a vaccine. The FVVA framework is designed to facilitate alignment across key stakeholders and to enhance decision-making around investment in vaccine development, policy-making, procurement, and introduction, particularly for vaccines intended for use in low- and middle-income countries.

RESULTS

The FVVA framework has three key elements. First, to enhance assessment, existing value-assessment methods and tools are adapted to include broader benefits of vaccines as well as opportunity costs borne by stakeholders. Second, to improve decision-making, a deliberative process is required to recognize the agency of stakeholders and to ensure country ownership of decision-making and priority setting. Third, the FVVA framework provides a consistent and evidence-based approach that facilitates communication about the full value of vaccines, helping to enhance alignment and coordination across diverse stakeholders.

CONCLUSIONS

The FVVA framework provides guidance for stakeholders organizing global-level efforts to promote investment in vaccines that are priorities for LMICs. By providing a more holistic view of the benefits of vaccines, its application also has the potential to encourage greater take-up by countries, thereby leading to more sustainable and equitable impacts of vaccines and immunization programmes.

Chemistry and Pharmacological diversity of Benzothiazepine - Excellent pathway to drug discovery

In this era of sporadic advancement in science and technology, a substantial amount of intervention is being set in motion to reduce health-related diseases. Discoveries from researchers have pinpointed the usefulness of heterocyclic compounds, amongst which benzothiazepine (BTZ) derivatives have been synthesized for their various pharmacological activities. This also contributes to their undeniable application in therapeutic medicine for the development of efficacious drugs. BTZs are compounds with a benzene ring fused with a thiazepine ring. This work contains several methods that have been used to synthesize 1,3-, 1,4-, 1,5-, and 4-1-benzothiazepine derivatives. In addition, up-to-date information about the crucial pharmacological activities of BTZ derivatives has been reviewed in this present study to appreciate their druggable potential in therapeutic medicine for drug development. Drug design and development have further been simplified with the implementation of computer aided approaches to predict biological interactions which can help in the design of several derivatives. Hence, the structural activity relationship (SAR), ADMET and the molecular docking studies of BTZ derivatives were discussed to further establish their interactions and safety in biological systems. This present work aims to expound on the reported chemistry and pharmacological propensity of BTZ moiety in relation to other relevant moieties to validate their potential as excellent pharmacophores in drug design and development.

Advances in development of new tuberculosis vaccines

PURPOSE OF REVIEW

Tuberculosis (TB) remains a global public health emergency and caused 1.6 million deaths in 2021. The aim of this review is to provide recent updates on advances in TB vaccine development for prevention and adjunct therapy.

RECENT FINDINGS

Targets use indications guiding late stage TB vaccine development have been established, namely: (i) Prevention of disease (PoD), (ii) Prevention of recurrent disease (PoR), (iii) Prevention of established infection in previously uninfected patients (PoI), and (iv) Adjunctive immunotherapy. Novel approaches include vaccines designed to induce immune responses beyond established CD4+, Th1-biased T cell immunity, novel animal models for use in challenge/protection studies, and controlled human infection models to generate vaccine efficacy data.

SUMMARY

Recent efforts at developing effective TB vaccines for prevention and adjunct treatment utilising new targets and technologies have yielded 16 candidate vaccines demonstrating proof of concept for inducing potentially protective immune responses to TB which is currently under evaluation in different stages of clinical trials.

Bacillus Calmette-Guérin-induced interleukin-10 inhibits S100A8/A9 production and hinders development of T helper type 1 memory in mice

Tuberculosis caused by Mycobacterium tuberculosis (M.tb) is one of the main causes of human death in the world. Bacillus Calmette-Guérin (BCG) provides limited protection in adolescents and adults. To explore the factors reducing efficacy of BCG vaccine, we assess the impacts of interleukin (IL)-10 and alarmins S100A8/A9 on T-cell memory. We found that BCG-induced IL-10 inhibited production of S100A8/A9 in human peripheral blood mononuclear cells (PBMCs) and murine splenocytes. S100A9 deficiency inhibited IFN-γ production by CD4⁺ T cells in the early phase of BCG immunization and hindered the development of effector memory T helper type 1 (Th1) cells, while IL-10 deficiency promoted Th1 memory and blocking IL-10 signaling enhanced Th1 protective recall response against M.tb. IL-10 inhibited the binding of transcription factor CCAAT enhancer binding protein beta to S100a8/a9 promoter leading to S100A8/A9 reduction. S100A8/A9 heterodimer enhanced the IFN-γ production via receptor for advanced glycation end products signaling in CD4⁺ T cells. Our results demonstrate a hurdle to development of Th1 memory after BCG immunization and clarify the mechanism of the regulation of Th1 memory by IL-10 and S100A8/A9.

The cost and cost-effectiveness of novel tuberculosis vaccines in low- and middle-income countries: A modeling study

BACKGROUND

Tuberculosis (TB) is preventable and curable but eliminating it has proven challenging. Safe and effective TB vaccines that can rapidly reduce disease burden are essential for achieving TB elimination. We assessed future costs, cost-savings, and cost-effectiveness of introducing novel TB vaccines in low- and middle-income countries (LMICs) for a range of product characteristics and delivery strategies.

METHODS AND FINDINGS

We developed a system of epidemiological and economic models, calibrated to demographic, epidemiological, and health service data in 105 LMICs. For each country, we assessed the likely future course of TB-related outcomes under several vaccine introduction scenarios, compared to a "no-new-vaccine" counterfactual. Vaccine scenarios considered 2 vaccine product profiles (1 targeted at infants, 1 at adolescents/adults), both assumed to prevent progression to active TB. Key economic inputs were derived from the Global Health Cost Consortium, World Health Organization (WHO) patient cost surveys, and the published literature. We estimated the incremental impact of vaccine introduction for a range of health and economic outcomes. In the base-case, we assumed a vaccine price of $4.60 and used a 1× per-capita gross domestic product (GDP) cost-effectiveness threshold (both varied in sensitivity analyses). Vaccine introduction was estimated to require substantial near-term resources, offset by future cost-savings from averted TB burden. From a health system perspective, adolescent/adult vaccination was cost-effective in 64 of 105 LMICs. From a societal perspective (including productivity gains and averted patient costs), adolescent/adult vaccination was projected to be cost-effective in 73 of 105 LMICs and cost-saving in 58 of 105 LMICs, including 96% of countries with higher TB burden. When considering the monetized value of health gains, we estimated that introduction of an adolescent/adult vaccine could produce $283 to 474 billion in economic benefits by 2050. Limited data availability required assumptions and extrapolations that may omit important country-level heterogeneity in epidemiology and costs.

CONCLUSIONS

TB vaccination would be highly impactful and cost-effective in most LMICs. Further efforts are needed for future development, adoption, and implementation of novel TB vaccines.

Accelerating research and development of new vaccines against tuberculosis: a global roadmap

To eliminate tuberculosis globally, a new, effective, and affordable vaccine is urgently needed, particularly for use in adults and adolescents in low-income and middle-income countries. We have created a roadmap that lists the actions needed to accelerate tuberculosis vaccine research and development using a participatory process. The vaccine pipeline needs more diverse immunological approaches, antigens, and platforms. Clinical development can be accelerated by validated preclinical models, agreed laboratory correlates of protection, efficient trial designs, and validated endpoints. Determining the public health impact of new tuberculosis vaccines requires understanding of a country's demand for a new tuberculosis vaccine, how to integrate vaccine implementation with ongoing tuberculosis prevention efforts, cost, and national and global demand to stimulate vaccine production. Investments in tuberculosis vaccine research and development need to be increased, with more diversity of funding sources and coordination between these funders. Open science is important to enhance the efficiency of tuberculosis vaccine research and development including early and freely available publication of study findings and effective mechanisms for sharing datasets and specimens. There is a need for increased engagement of industry vaccine developers, for increased political commitment for new tuberculosis vaccines, and to address stigma and vaccine hesitancy. The unprecedented speed by which COVID-19 vaccines have been developed and introduced provides important insight for tuberculosis vaccine research and development.

Effectiveness of Preventive Therapy for Persons Exposed at Home to Drug-Resistant Tuberculosis, Karachi, Pakistan

Fluoroquinolone-based preventive therapy reduced risk for tuberculosis disease by 65%.

In Karachi, Pakistan, a South Asian megacity with a high prevalence of tuberculosis (TB) and low HIV prevalence, we assessed the effectiveness of fluoroquinolone-based preventive therapy for drug-resistant (DR) TB exposure. During February 2016–March 2017, high-risk household contacts of DR TB patients began a 6-month course of preventive therapy with a fluoroquinolone-based, 2-drug regimen. We assessed effectiveness in this cohort by comparing the rate and risk for TB disease over 2 years to the rates and risks reported in the literature. Of 172 participants, TB occurred in 2 persons over 336 person-years of observation. TB disease incidence rate observed in the cohort was 6.0/1,000 person-years. The incidence rate ratio ranged from 0.29 (95% CI 0.04–1.3) to 0.50 (95% CI 0.06–2.8), with a pooled estimate of 0.35 (95% CI 0.14–0.87). Overall, fluoroquinolone-based preventive therapy for DR TB exposure reduced risk for TB disease by 65%.