A global regulatory science agenda for vaccines

Four-Color Pseudovirus-Based Neutralization Assay: A Rapid Method for Evaluating Neutralizing Antibodies Against Quadrivalent Hand, Foot, and Mouth Disease Vaccine

BACKGROUND/OBJECTIVES

Enterovirus 71 (EV71) and coxsackieviruses A16 (CA16), A10 (CA10), and A6 (CA6) are the primary pathogens that cause hand, foot, and mouth disease (HFMD). Currently, many manufacturers are developing bivalent, trivalent, and tetravalent vaccines that target these antigens. Cell-based neutralization assay (CBNA), the gold standard for detecting neutralizing antibodies (NtAbs), which are used as indicators of HFMD vaccine efficacy, has several limitations. We aimed to develop a novel assay for detecting NtAbs against a quadrivalent HFMD vaccine.

METHODS

We developed a four-color pseudovirus-based neutralization assay (PBNA), utilizing fluorescent reporter genes, to rapidly evaluate neutralizing antibodies against EV71, CA16, CA10, and CA6 in multivalent vaccines and compared it with CBNA.

RESULTS

PBNA could rapidly and simultaneously detect NtAbs against the four serotypes and required lesser amounts of sera compared to CBNA. A good consistency in determining NtAb titers was observed for PBNA and CBNA.

CONCLUSIONS

PBNA provides a robust tool for evaluating the efficacy of multivalent HFMD vaccines and conducting seroepidemiological studies.

A screening study on the detection strain of Coxsackievirus A6: the key to evaluating neutralizing antibodies in vaccines

The increasing incidence of diseases caused by Coxsackievirus A6 (CV-A6) and the presence of various mutants in the population present significant public health challenges. Given the concurrent development of multiple vaccines in China, it is challenging to objectively and accurately evaluate the level of neutralizing antibody response to different vaccines. The choice of the detection strain is a crucial factor that influences the detection of neutralizing antibodies. In this study, the National Institutes for Food and Drug Control collected a prototype strain (Gdula), one subgenotype D1, as well as 13 CV-A6 candidate vaccine strains and candidate detection strains (subgenotype D3) from various institutions and manufacturers involved in research and development. We evaluated cross-neutralization activity using plasma from naturally infected adults (n = 30) and serum from rats immunized with the aforementioned CV-A6 strains. Although there were differences between the geometric mean titer (GMT) ranges of human plasma and murine sera, the overall trends were similar. A significant effect of each strain on the neutralizing antibody test (MAX/MIN 48.0 ∼16410.3) was observed. Among all strains, neutralization of the S112 strain by 15 different sera resulted in higher neutralizing antibody titers (GMTS112 = 132.0) and more consistent responses across different genotypic immune sera (MAX/MIN = 48.0). Therefore, S112 may serve as a detection strain for NtAb testing in various vaccines, minimizing bias and making it suitable for evaluating the immunogenicity of the CV-A6 vaccine.

Trends in Adverse Drug Reactions Among Children: Evidence from Jiangsu Province of China, 2010-2019

BACKGROUND

Medication safety among children represents an underrecognized public health concern worldwide, yet little evidence was found in China. This study aimed to examine trends in rates of pediatric adverse drug reaction (ADR) reports in Jiangsu Province of China with a catchment population of more than 11 million children.

METHODS

Data for children aged under 15 years were extracted from the spontaneous reporting system of ADR surveillance in Jiangsu Province. Suspected therapeutic agents for ADRs were coded using the Anatomical Therapeutic Chemical classification system. We used the Chinese modification of the International Classification of Diseases, Tenth Revision, to group primary diseases, and the Medical Dictionary for Regulatory Activities to classify the manifestation of ADRs. We used Joinpoint to estimate age-adjusted ADR rates stratified by sex from July 2010 to June 2019, and further by specific features, including patient characteristics, main suspected therapeutic medications, primary diseases, and ADRs. We used the percentage change annualized estimator to evaluate trends over time.

RESULTS

A total of 79,903 ADR reports were identified among children aged under 15 years, which accounted for 11.4% of all ADRs reported in Jiangsu Province during the same period. The age-adjusted ADR report rates increased significantly from 66.20 to 96.76 per 100,000 children during the period July 2010-June 2019, with an annual increase of 4.9% (95% confidence interval 1.3-8.5%; p value 0.014). Of all ADR reports, there were 47,774 (59.8%) boys and 32,129 (40.2%) girls. Children aged 0-4 years accounted for more than half of the ADR reports (n = 47,680, 59.7%). Skin and subcutaneous tissue disorders were the most frequently reported ADRs (45,773, 57.3%). Respiratory diseases were the most commonly observed medical conditions in relation to pediatric ADRs, accounting for 68.8% (n = 54,940) of all ADR reports, and anti-infectives for systemic use consistently represented over time the most common medication group, contributing to 69.8% of all reports. A reduction in ADR report rates was observed for vaccines, with an annual decrease of 19% in children.

CONCLUSIONS

ADRs remain a public health challenge among the vulnerable pediatric populations. Findings from the present study call for continuing efforts in ADR prevention and medication safety improvement in children.

Review on Drug Regulatory Science Promoting COVID-19 Vaccine Development in China

Regulatory science is a discipline that uses comprehensive methods of natural science, social science, and humanities to provide support for administrative decision-making through the development of new tools, standards, and approaches to assess the safety, efficacy, quality, and performance of regulated products. During the pandemics induced by infectious diseases, such as H1N1 flu, severe acute respiratory syndrome (SARS), and Middle East respiratory syndrome (MERS), regulatory science strongly supported the development of drugs and vaccines to respond to the viruses. In particular, with the support of research on drug regulatory science, vaccines have played a major role in the prevention and control of coronavirus disease 2019 (COVID-19). This review summarizes the overall state of the vaccine industry, research and development (R&D) of COVID-19 vaccines in China, and the general state of regulatory science and supervision for vaccines in China. Further, this review highlights how regulatory science has promoted the R&D of Chinese COVID-19 vaccines, with analyses from the aspects of national-level planning, relevant laws and regulations, technical guidelines, quality control platforms, and post-marketing supervision. Ultimately, this review provides a reference for the formulation of a vaccine development strategy in response to the current pandemic and the field of vaccine development in the post-pandemic era, as well as guidance on how to better respond to emerging and recurring infectious diseases that may occur in the future.

Increasing efficiency in vaccine Production: A primer for change

The COVID-19 pandemic has highlighted the importance of vaccines as public health and pandemic preparedness tools and amplified the importance of issues ranging from equitable distribution to reliable supply of quality, affordable vaccines. These issues however are not new. Delays in time from the first dose in a high-income country to introduction at scale in a low-income country can take years. These delays are driven by several challenges, some of which are unique to the vaccine development ecosystem. The patenting and overall intellectual property (IP) protection are complex, regulatory oversight is rigorous, manufacturing processes require technical support or know-how transfer from the innovator, and market dynamics create obstacles to delivering at scale. However, there are opportunities to accelerate the introduction of vaccines at scale in low and middle-income countries. To identify those opportunities, this paper provides an overview of the vaccine research and development process and where reform of the current system could increase access.

Emerging viruses and current strategies for vaccine intervention

During the past decade several notable viruses have suddenly emerged from obscurity or anonymity to become serious global health threats, provoking concern regarding their sustained epidemic transmission in immunologically naive human populations. With each new threat comes the call for rapid vaccine development. Indeed, vaccines are considered a critical component of disease prevention for emerging viral infections because, in many cases, other medical options are limited or non‐existent, or that infections result in such a rapid clinical deterioration that the effectiveness of therapeutics is limited. While classic approaches to vaccine development are still amenable to emerging viruses, the application of molecular techniques in virology has profoundly influenced our understanding of virus biology, and vaccination methods based on replicating, attenuated and non‐replicating virus vector approaches have become useful vaccine platforms. Together with a growing understanding of viral disease emergence, a range of vaccine strategies and international commitment to underpin development, vaccine intervention for new and emerging viruses may become a possibility.

[Regulatory science in public health: What are we talking about?]

This article sheds light on a concept little known to public health actors in France: regulatory science, used to describe the range of scientific activities used to produce the knowledge mobilized to support, develop or adapt public policy decisions. The objective is to understand how the expression appeared in the mid-1980s and was formalized into a sociological concept by the American writer Sheila Jasanoff in 1990, and has gradually imposed itself in American, Japanese and European regulatory agencies as a new scientific discipline. The article examines the evolution of the concept and the various approaches proposed to define regulatory science. It highlights its hybrid and heterogeneous nature, underlining the different characteristics that the expression covers according to the institution which formulates it (FDA, EMA, PMDA) and the scope of application that it covers. Based on concrete examples of the application of regulatory science practices in three broad areas of health risk, the paper focuses on the role of research in the decision-making process by showing how the emergence of new methods designed to strengthen the regulatory capacities of regulators and the role of academic communities associated with this approach, contribute to the strengthening of public health policies in France and worldwide.

Social engineering of societal knowledge in livestock science: Can we be more empathetic?

Questions are raised in effective utilization of farmer’s wisdom by communities in their farming. Planners support to livelihood emphasize mostly of inputs from outside and not setting up sustainable goals. Formal institutions and planners of program are finding constraints and sceptical in wider dissemination of indigenous knowledge research system (IKRS). This is in spite of evidence that considerable number of farmer’s in livestock sector depends on IKRS. In this context, it is pertinent to showcase dissemination potential of these knowledge system(s) in larger geographical areas. The review illustrates different challenges encountered while control of livestock ailments like ectoparasite infestation through IKRS. Several times, it was opinioned to provide or share IKRS to thwart ailments in a specific region. This is interesting as it was narrated how formal system is unable to recognize farmer’s problem and challenges in integrating these sustainable practices. It has to be noted that disseminating activities seldom takes into account the experimental potential of farmers. This review paper articulates various evidences generated in enhancing diffusion thereby dissemination of IKRS. The nature of support extended by IKRS in entrepreneurial activity of smallholder farming units did not get adequate recognition. There needs to be minimum standard protocol in deriving benefit from such low-cost alternative technologies. This will enrich incremental innovation activities as per location specific need and provide scope for wider dissemination.

Human capital gaps in vaccine development: an issue for global vaccine development and global health

Despite the success of vaccines in reducing the morbidity and mortality associated with infectious diseases, many infectious diseases, both newly emerging and well known, lack vaccines. The global capability for beginning-to-end vaccine development has become limited, primarily owing to a scarcity of human capital necessary to guide the development of novel vaccines from the laboratory to the marketplace. Here, we identify and discuss the gaps in human capital necessary for robust vaccine development and make recommendations to begin to address these deficiencies.

Pharmacokinetics and biodistribution of squalene-containing emulsion adjuvant following intramuscular injection of H5N1 influenza vaccine in mice

Squalene is a component of oil-in-water emulsion adjuvants developed for potential use in some influenza vaccines. The biodistribution of the squalene-containing emulsion adjuvant (AddaVax™) alone and as part of complete H5N1 vaccine was quantified in mechanistically and toxicologically relevant target tissues up to 336 h (14 days) following injection into quadriceps muscle. At 1 h, about 55% of the intramuscularly injected dose of squalene was detected in the local quadriceps muscles and this decreased to 26% at 48 h. Twenty-four hours after the injection, approximately 5%, 1%, and 0.6% of the injected dose was detected in inguinal fat, draining lymph nodes, and sciatic nerve, respectively. The peak concentration for kidney, brain, spinal cord, bone marrow, and spleen was each less than 1% of the injected dose, and H5N1 antigen did not significantly alter the biodistribution of squalene to these tissues. The area-under-blood-concentration curve (AUC) and peak blood concentration (Cmax) of squalene were slightly higher (20-25%) in the presence of H5N1 antigen. A population pharmacokinetic model-based statistical analysis identified body weight and H5N1 antigen as covariates influencing the clearance of squalene. The results contribute to the body of knowledge informing benefit-risk analyses of squalene-containing emulsion vaccine adjuvants.

Challenges and opportunities of using liquid chromatography and mass spectrometry methods to develop complex vaccine antigens as pharmaceutical dosage forms

Liquid chromatographic methods, combined with mass spectrometry, offer exciting and important opportunities to better characterize complex vaccine antigens including recombinant proteins, virus-like particles, inactivated viruses, polysaccharides, and protein-polysaccharide conjugates. The current abilities and limitations of these physicochemical methods to complement traditional in vitro and in vivo vaccine potency assays are explored in this review through the use of illustrative case studies. Various applications of these state-of-the art techniques are illustrated that include the analysis of influenza vaccines (inactivated whole virus and recombinant hemagglutinin), virus-like particle vaccines (human papillomavirus and hepatitis B), and polysaccharide linked to protein carrier vaccines (pneumococcal). Examples of utilizing these analytical methods to characterize vaccine antigens in the presence of adjuvants, which are often included to boost immune responses as part of the final vaccine dosage form, are also presented. Some of the challenges of using chromatographic and LC-MS as physicochemical assays to routinely test complex vaccine antigens are also discussed.

Collaborative studies on the development of national reference standards for potency determination of H7N9 influenza vaccine

The outbreak of human infections of a novel avian influenza virus A (H7N9) prompted the development of the vaccines against this virus. Like all types of influenza vaccines, H7N9 vaccine must be tested for its potency prior to being used in humans. However, the unavailability of international reference reagents for the potency determination of H7N9 vaccines substantially hinders the progress in vaccine development. To facilitate clinical development, we enlisted 5 participants in a collaborative study to develop critical reagents used in Single Radial Immunodiffusion (SRID), the currently acceptable assay for potency determination of influenza vaccine. Specifically, the hemagglutinin (HA) content of one vaccine bulk for influenza A (H7N9), herein designated as Primary Liquid Standard (PLS), was determined by SDS-PAGE. In addition, the freeze-dried antigen references derived from PLS were prepared to enhance the stability for long term storage. The final HA content of lyophilized antigen references were calibrated against PLS by SRID assay in a collaborative study. Importantly, application of these national reference standards to potency analyses greatly facilitated the development of H7N9 vaccines in China.

Enhancing Vaccine Safety Capacity Globally: A Lifecycle Perspective

Major vaccine safety controversies have arisen in several countries beginning in the last decades of 20th century. Such periodic vaccine safety controversies are unlikely to go away in the near future as more national immunization programs mature with near elimination of target vaccine-preventable diseases that result in relative greater prominence of adverse events following immunizations, both true reactions and temporally coincidental events. There are several ways in which vaccine safety capacity can be improved to potentially mitigate the impact of future vaccine safety controversies. This paper aims to take a "lifecycle" approach, examining some potential pre- and post-licensure opportunities to improve vaccine safety, in both developed (specifically U.S. and Europe) and low- and middle-income countries.

Enhancing vaccine safety capacity globally: A lifecycle perspective

Major vaccine safety controversies have arisen in several countries beginning in the last decades of 20th century. Such periodic vaccine safety controversies are unlikely to go away in the near future as more national immunization programs mature with near elimination of target vaccine-preventable diseases that result in relative greater prominence of adverse events following immunizations, both true reactions and temporally coincidental events. There are several ways in which vaccine safety capacity can be improved to potentially mitigate the impact of future vaccine safety controversies. This paper aims to take a "lifecycle" approach, examining some potential pre- and post-licensure opportunities to improve vaccine safety, in both developed (specifically U.S. and Europe) and low- and middle-income countries.

Comparative Safety of Vaccine Adjuvants: A Summary of Current Evidence and Future Needs

Use of highly pure antigens to improve vaccine safety has led to reduced vaccine immunogenicity and efficacy. This has led to the need to use adjuvants to improve vaccine immunogenicity. The ideal adjuvant should maximize vaccine immunogenicity without compromising tolerability or safety. Unfortunately, adjuvant research has lagged behind other vaccine areas such as antigen discovery, with the consequence that only a very limited number of adjuvants based on aluminium salts, monophosphoryl lipid A and oil emulsions are currently approved for human use. Recent strategic initiatives to support adjuvant development by the National Institutes of Health should translate into greater adjuvant choices in the future. Mechanistic studies have been valuable for better understanding of adjuvant action, but mechanisms of adjuvant toxicity are less well understood. The inflammatory or danger-signal model of adjuvant action implies that increased vaccine reactogenicity is the inevitable price for improved immunogenicity. Hence, adjuvant reactogenicity may be avoidable only if it is possible to separate inflammation from adjuvant action. The biggest remaining challenge in the adjuvant field is to decipher the potential relationship between adjuvants and rare vaccine adverse reactions, such as narcolepsy, macrophagic myofasciitis or Alzheimer's disease. While existing adjuvants based on aluminium salts have a strong safety record, there are ongoing needs for new adjuvants and more intensive research into adjuvants and their effects.

Regulatory science accelerates the development of biotechnology drugs and vaccines by NIFDC

The Chinese National Institutes for Food and Drug Control (NIFDC) is the national laboratory responsible for the quality control of pharmaceutical products. In recent years, to ensure the quality of biological products and improve the research and development (R&D) of new biological drugs and vaccines, NIFDC conducted a series of regulatory science studies on key technologies for quality control and evaluation, and established a quality control and evaluation platform for biological drugs and vaccines. These studies accelerated the R&D of the biological drugs and vaccines in China and assured their safety and efficacy. In this paper, NIFDC's duties and achievements in the biological drug and vaccine field are summarized.

Chinese vaccine products go global: vaccine development and quality control

Through the continuous efforts of several generations, China has become one of the few countries in the world that is capable of independently addressing all the requirements by the Expanded Program on Immunization. Regulatory science is applied to continuously improve the vaccine regulatory system. Passing the prequalification by WHO has allowed Chinese vaccine products to go global. Chinese vaccine products not only secure disease prevention and control domestically but also serve the needs for international public health. This article describes the history of Chinese vaccine development, the current situation of Chinese vaccine industry and its contribution to the prevention and control of infectious diseases. We also share our experience of national quality control and vaccine regulation during the past decades. China's experience in vaccine development and quality control can benefit other countries and regions worldwide, including the developing countries.

Better vaccines for healthier life. Part II. Conference report of the DCVMN International 14th Annual General Meeting Hanoi, Vietnam

New vaccines are required to meet the public health challenges of the next generation and many unmet global health needs can be addressed by developing countries vaccine manufacturers such as lower-cost vaccines based on single-dose, thermostable formulations, efficacious in children with compromised gastrointestinal tracts. GMP compliance is also a challenge, as sometimes innovation and clinical development focus is not accompanied by command of scale-up and quality assurance for large volume manufacturing and supply. Identifying and addressing such challenges, beyond cost and cold-chain space, including safety considerations and health worker behavior, regulatory alliances and harmonization to foster access to vaccines, will help countries to ensure sustainable immunization. There needs to be continuous and close management of the global vaccine supply both at national and international levels, requiring careful risk management, coordination and cooperation with manufacturers. Successful partnership models based on sharing a common goal, mutual respect and good communication were discussed among stakeholders.

The regulatory sciences for stem cell-based medicinal products

Over the past few years, several new achievements have been made from stem cell studies, many of which have moved up from preclinical stages to early, or from early to middle or late, stages thanks to relatively safe profile and preliminary evidence of effectiveness. Moreover, some stem cell-based products have been approved for marketing by different national regulatory authorities. However, many critical issues associated mainly with incomplete understanding of stem cell biology and the relevant risk factors, and lack of effective regulations still exist and need to be urgently addressed, especially in countries where establishment of appropriate regulatory system just commenced. More relevantly, the stem cell regulatory sciences need to be established or improved to more effectively evaluate quality, safety and efficacy of stem cell products, and for building up the appropriate regulatory framework. In this review, we summarize some new achievements in stem cell studies, especially the preclinical and clinical studies, the existing regulations, and the associated challenges, and we then propose some considerations for improving stem cell regulatory sciences with a goal of promoting the steadfast growth of the well-regulated stem cell therapies abreast of evolvement of stem cell sciences and technologies.

A physiologically-based pharmacokinetic (PBPK) model of squalene-containing adjuvant in human vaccines

Squalene is used in the oil phase of certain emulsion vaccine adjuvants, but its fate as a vaccine component following intramuscular (IM) injection in humans is unknown. In this study, we constructed a physiologically-based pharmacokinetic (PBPK) model for intramuscularly injected squalene-in-water (SQ/W) emulsion, in order to make a quantitative estimation of the tissue distribution of squalene following a single IM injection in humans. The PBPK model incorporates relevant physicochemical properties of squalene; estimates of the time course of cracking of a SQ/W emulsion; anatomical and physiological parameters at the injection site and beyond; and local, preferential lymphatic transport. The model predicts that a single dose of SQ/W emulsion will be removed from human deltoid muscle within six days following IM injection. The major proportion of the injected squalene will be distributed to draining lymph nodes and adipose tissues. The model indicates slow decay from the latter compartment most likely due to partitioning into neutral lipids and a low rate of squalene biotransformation there. Parallel pharmacokinetic modeling for mouse muscle suggests that the kinetics of SQ/W emulsion correspond to the immunodynamic time course of a commercial squalene-containing adjuvant reported in that species. In conclusion, this study makes important pharmacokinetic predictions of the fate of a squalene-containing emulsion in humans. The results of this study may be relevant for understanding the immunodynamics of this new class of vaccine adjuvants and may be useful in future quantitative risk analyses that incorporate mode-of-action data.