Stability of heat stable, live attenuated Rotavirus vaccine (ROTASIIL®)

Vaccine cold chain management and cold storage technology to address the challenges of vaccination programs

The outbreaks of infectious diseases that spread across countries have generally existed for centuries. An example is the occurrence of the COVID-19 pandemic in 2020, which led to the loss of lives and economic depreciation. One of the essential ways of handling the spread of viruses is the discovery and administration of vaccines. However, the major challenges of vaccination programs are associated with the vaccine cold chain management and cold storage facilities. This paper discusses how vaccine cold chain management and cold storage technology can address the challenges of vaccination programs. Specifically, it examines different systems for preserving vaccines in either liquid or frozen form to help ensure that they are not damaged during distribution from manufacturing facilities. Furthermore, A vaccine is likely to provide very low efficacy when it is not properly stored. According to preliminary studies, the inability to store vaccine properly is partly due to the incompetency of many stakeholders, especially in technical matters. The novelty of this study is to thoroughly explore cold storage technology for a faster and more comprehensive vaccine distribution hence it is expected to be one of the reference and inspiration for stakeholders.

Quantitative regulation of the thermal stability of enveloped virus vaccines by surface charge engineering to prevent the self-aggregation of attachment glycoproteins

The development of thermostable vaccines can relieve the bottleneck of existing vaccines caused by thermal instability and subsequent poor efficacy, which is one of the predominant reasons for the millions of deaths caused by vaccine-preventable diseases. Research into the mechanism of viral thermostability may provide strategies for developing thermostable vaccines. Using Newcastle disease virus (NDV) as model, we identified the negative surface charge of attachment glycoprotein as a novel determinant of viral thermostability. It prevented the temperature-induced aggregation of glycoprotein and subsequent detachment from virion surface. Then structural stability of virion surface was improved and virus could bind to and infect cells efficiently after heat-treatment. Employing the approach of surface charge engineering, thermal stability of NDV and influenza A virus (IAV) vaccines was successfully improved. The increase in the level of vaccine thermal stability was determined by the value-added in the negative surface charge of the attachment glycoprotein. The engineered live and inactivated vaccines could be used efficiently after storage at 37°C for at least 10 and 60 days, respectively. Thus, our results revealed a novel surface-charge-mediated link between HN protein and NDV thermostability, which could be used to design thermal stable NDV and IAV vaccines rationally.

Rotavirus vaccines: progress and new developments

INTRODUCTION

Rotavirus is the primary cause of severe acute gastroenteritis among children under the age of five globally, leading to 128,500 to 215,000 vaccine-preventable deaths annually. There are six licensed oral, live-attenuated rotavirus vaccines: four vaccines pre-qualified for global use by WHO, and two country-specific vaccines. Expansion of rotavirus vaccines into national immunization programs worldwide has led to a 59% decrease in rotavirus hospitalizations and 36% decrease in diarrhea deaths due to rotavirus in vaccine-introducing countries.

AREAS COVERED

This review describes the current rotavirus vaccines in use, global coverage, vaccine efficacy from clinical trials, and vaccine effectiveness and impact from post-licensure evaluations. Vaccine safety, particularly as it relates to the risk of intussusception, is also summarized. Additionally, an overview of candidate vaccines in the pipeline is provided.

EXPERT OPINION

Considerable evidence over the past decade has demonstrated high effectiveness (80-90%) of rotavirus vaccines at preventing severe rotavirus disease in high-income countries, although the effectiveness has been lower (40-70%) in low-to-middle-income countries. Surveillance and research should continue to explore modifiable factors that influence vaccine effectiveness, strengthen data to better evaluate newer rotavirus vaccines, and aid in the development of future vaccines that can overcome the limitations of current vaccines.

Effect of rotavirus genetic diversity on vaccine impact

Group A rotaviruses (RVAs) are the leading cause of gastroenteritis, causing 0.2 million deaths and several million hospitalisations globally each year. Four rotavirus vaccines (Rotarix^TM , RotaTeq^TM , Rotavac^® and ROTASIIL^® ) have been pre-qualified by the World Health Organization (WHO), but the two newly pre-qualified vaccines (Rotavac^® and ROTASIIL^® ) are currently only in use in Palestine and India, respectively. In 2009, WHO strongly proposed that rotavirus vaccines be included in the routine vaccination schedule of all countries around the world. By the end of 2019, a total of 108 countries had administered rotavirus vaccines, and 10 countries have currently been approved by Gavi for the introduction of rotavirus vaccine in the near future. With 39% of global coverage, rotavirus vaccines have had a substantial effect on diarrhoeal morbidity and mortality in different geographical areas, although efficacy appears to be higher in high income settings. Due to the segmented RNA genome, the pattern of RVA genotypes in the human population is evolving through interspecies transmission and/or reassortment events for which the vaccine might be less effective in the future. However, despite the relative increase in some particular genotypes after rotavirus vaccine use, the overall efficacy of rotavirus mass vaccination worldwide has not been affected. Some of the challenges to improve the effect of current rotavirus vaccines can be solved in the future by new rotavirus vaccines and by vaccines currently in progress.

Evolutionary analysis of rotavirus G1P[8] strains from Chennai, South India

Rotaviruses by virtue of its segmented genome generate numerous genotypes. G1P[8] is the most common genotype reported globally. We intend to identify the evolutionary differences among G1P[8] strains from the study with vaccine strains. Stool samples collected from children <5 years were screened for rotavirus antigen by enzyme linked immunosorbent assay. The samples that tested positive for rotavirus were subjected to VP7 and VP4 semi-nested RT-PCR. Sanger sequencing was performed in randomly chosen VP7 and VP4 rotavirus strains. Phylogenetic analysis showed less homology between study strains and vaccine strains and they were placed in different lineages. The VP7 and VP4 proteins of rotavirus were analyzed by two different platforms to identify the amino acid substitutions in the epitope regions. Nine amino acid substitutions with respect to Rotarix®, RotaTeq® and Rotasiil®-V66A, A/T68S, Q72R, N94S, D100E, T113I, S123N, M217T, and I281T were observed in VP7. There were five amino acid substitutions-S145G, N/D195G, N113D, N/I78T, E150D in VP4 (VP8 portion) with respect to Rotarix® and RotaTeq® vaccine strains. M217T substitution in VP7 (epitope 7-2) and N113D, D195G substitution in VP4 (epitope 8-3, 8-1) confer changes in polarity/electrical charge with respect to vaccine strains, thus indicating the need for continued surveillance.

Cold Chain Management by Healthcare Providers at a District in Ghana: A Mixed Methods Study

Background

Despite the relevance of cold chain management in maintaining the potency of vaccines, gaps still exist in the ability of healthcare practitioners to maintain the cold chain system effectively. Thus, the current study sought to assess healthcare providers' knowledge, attitudes, practices, and challenges regarding cold chain management.

Methods

A concurrent mixed methods study was conducted at twelve facilities in the Sekyere Central District of Ghana. Eighty-six (86) participants took part in a survey that assessed their “cold chain management” knowledge and attitudes. Twelve (12) cold chain sites within the district were also observed in respect of their cold chain management practices. Eleven key informants were additionally interviewed to explore their challenges on cold chain management. Quantitative data were analyzed using descriptive (frequencies, percentages, means, standard deviations, ranges) and inferential statistics (Spearman's rho correlation). Qualitative data were inductively analyzed into themes which described participants' challenges on cold chain management.

Results

Majority of the participants scored ≥70% on knowledge (68.6%) and attitudes (67.4%) toward cold chain management. However, there was a very weak positive and statistically insignificant relationship between participant's knowledge and attitudes toward cold chain management (r = 0.109, p = 0.317). Regarding cold chain management practices, majority of the facilities had their vaccine vial monitors attached to the vaccines (8/12, 66.7%), had functional fridge tags (8/12, 66.7%), and an appropriate refrigerator to store vaccines (7/12, 58.3%). However, the study observed that 91.7% (11/12) of the facilities did not have policies and guidelines on cold chain management while all 12 facilities (100%) did not have a contingency plan in place for equipment. With regards to the cold chain management challenges, participants raised concerns about inadequate personnel, erratic power supply, logistical constraints, and transportation difficulties.

Conclusion

Although majority of the participants had good knowledge and attitude towards cold chain management, there was a weak association between them. This implies that good knowledge may not necessarily influence good attitudes towards cold chain management and vice versa. The extent to which facilities support cold chain management practices was suboptimal. Participants encountered a number of challenges which prevented them from managing the vaccine cold chain system effectively. We recommend continual professional education for cold chain practitioners, provision of adequate human and material resources for cold chain management, and enhanced monitoring and evaluation of cold chain activities. Future studies should quantitatively measure individual participants' knowledge, attitudes, practices, and challenges on cold chain management so that we can establish the relationships that exist between these components.

Translation of Polymeric Microneedles for Treatment of Human Diseases: Recent Trends, Progress, and Challenges

The ongoing search for biodegradable and biocompatible microneedles (MNs) that are strong enough to penetrate skin barriers, easy to prepare, and can be translated for clinical use continues. As such, this review paper is focused upon discussing the key points (e.g., choice polymeric MNs) for the translation of MNs from laboratory to clinical practice. The review reveals that polymers are most appropriately used for dissolvable and swellable MNs due to their wide range of tunable properties and that natural polymers are an ideal material choice as they structurally mimic native cellular environments. It has also been concluded that natural and synthetic polymer combinations are useful as polymers usually lack mechanical strength, stability, or other desired properties for the fabrication and insertion of MNs. This review evaluates fabrication methods and materials choice, disease and health conditions, clinical challenges, and the future of MNs in public healthcare services, focusing on literature from the last decade.

Stability of lyophilized and spray dried vaccine formulations

Liquid formulations of vaccines are subject to instabilities that result from degradation processes that proceed via a variety of physical and chemical pathways. In dried formulations, such as those prepared by lyophilization or spray drying, many of these degradation pathways may be avoided or inhibited. Thus, the stability of vaccine formulations can be enhanced significantly in the absence of bulk water. Potential advantages of dry vaccine formulations include extended shelf lives and less stringent cold-chain storage requirements, both of which offer possibilities of reduced vaccine wastage and facilitated distribution to resource-poor areas. Lyophilization and spray drying represent the most common methods of stabilizing vaccines through drying. This article reviews several lyophilized and spray dried vaccines that address a diverse set of pathogens, as well as some of the assays used to quantify their stability. Recent dry vaccine trends include needle-free delivery of dry powder via non-parenteral routes of administration and the incorporation of advanced vaccine adjuvants into formulations, which further contribute to the goal of increasing vaccine distribution to resource-poor areas. Challenges associated with development of these newer technologies are also discussed.

Effectiveness of the oral human attenuated pentavalent rotavirus vaccine (RotaTeq™) postlicensure: a meta-analysis-2006-2020

BACKGROUND

Rotavirus (RV), which causes RV-associated gastroenteritis (RVGE), has accounted for considerable morbidity. We aimed to assess the effectiveness (VE) of the oral pentavalent RV vaccine (RotaTeq™) in real-world settings in children and infants with gastroenteritis.

METHODS

We performed a systematic search for peer-reviewed studies published between 1 January 2006 and 1 May 2020 and a meta-analysis to calculate the VE of RotaTeq™ vaccine. The primary outcome was the pooled three-dose vaccine VE. Stratified analysis of the vaccine VEs was performed according to dosages, study design, population age, socioeconomic status (SES), introduction condition, control group types, outcomes of RV disease, and RV strains.

RESULTS

After screening 2359 unique records, 28 studies were included and meta-analyzed. The overall VE estimate was 84% (95% confidence interval [CI], 80-87%). Stratified analyses revealed a nonnegligible impact of factors such as study design and SES. Other factors did not show great impart to VE with no significant differences between groups.

CONCLUSIONS

RotaTeq™ is effective against RV infection, especially in high-income countries. Adopting suitable study methods and expansion of RV surveillance in low-income regions is crucial to assess VE in real-life settings and provide feasible vaccine regimens to improve vaccine VE.

The performance of licensed rotavirus vaccines and the development of a new generation of rotavirus vaccines: a review

Rotavirus, which causes acute gastroenteritis and severe diarrhea, has posed a great threat to children worldwide over the last 30 y. Since no specific drugs and therapies against rotavirus are available, vaccination is considered the most effective method of decreasing the morbidity and mortality related to rotavirus-associated gastroenteritis. To date, six rotavirus vaccines have been developed and licensed by local governments. Notably, Rotarix™ and RotaTeq™ have been recommended as universal agents against rotavirus infection by the World Health Organization; however, lower efficacies were found in less-developed and developing regions with medium and high child mortality than well-developed ones with low child mortality. For now, two promising novel vaccines, Rotavac™ and RotaSiil™ were pre-qualified by the World Health Organization in 2018. Other rotavirus vaccines in the pipeline including neonatal strain (RV3-BB) and several non-replicating rotavirus vaccines with a parenteral delivery strategy are currently undergoing investigation, with the potential to improve the performance of, and eliminate the safety concerns associated with, previous live oral rotavirus vaccines. This paper reviews the important developments in rotavirus vaccines in the last 20 y and discusses problems and challenges that require investigation in the future.

Advancing innovation for vaccine manufacturers from developing countries: Prioritization, barriers, opportunities

Development of novel vaccines and improving existing vaccines is critical to addressing areas of unmet or under-addressed health needs globally and to improving existing vaccination coverage and equity. However, vaccine innovation is costly and highly complex. To understand how vaccine manufacturers from developing countries approach innovation, a survey was conducted among company members of the Developing Countries Vaccine Manufacturers Network, in collaboration with the Clinton Health Access Initiative. The survey confirmed that vaccine manufacturers from developing countries are committed to vaccine innovation: 95% of respondents have interest in pursuing vaccine innovation, with strategies targeted towards supplying to low- and middle-income countries. Key barriers to innovation were also surveyed, with respondents highlighting challenges regarding access to in-licensing or joint venture partnerships, financing, and regulatory barriers. Opportunities for innovation are also discussed.

[Phylodynamic characteristics of the Russian population of rotavirus А (Reoviridae: Sedoreovirinae: Rotavirus) based on the VP6 gene]

INTRODUCTION

Rotavirus A is one of the leading causes of acute gastroenteritis in children in the first years of life. Rotavirus infection is currently classified as a preventable infection. The most abundant rotavirion protein is VP6.

MATERIAL AND METHODS

Phylogenetic analysis and calculation of phylodynamic characteristics were carried out for 262 nucleotide sequences of the VP6 gene of rotavirus species A, isolated in Russia, using the BEAST v.1.10.4 software package. The derivation and analysis of amino acid sequences was performed using the MEGAX program.

RESULTS

This study provides phylodynamic characteristics of the rotaviruses in Russia based on the sequences coding VP6 protein. Bayesian analysis showed the circulation of rotaviruses of three sublineages of genotype I1 and three sublineages of genotype I2 in Russia. The level of accumulation of mutations was established, which turned out to be similar for genotypes I1 and I2 and amounted to 7.732E-4 and 1.008E-3 nucleotides/site/year, respectively. The effective population sizes based on nucleotide sequences of the VP6 I1 and I2 genotypes are relatively stable while after the 2000s there is a tendency of its decreasing. Comparative analysis of the amino acid sequences in the region of the intracellular neutralization sites A (231-260 aa) and B (265-292 aa) made it possible to reveal a mutation in position V252I in a proportion of Russian strains of genotype I1 some strains of genotypes I1 and I2 had mutation I281V. These substitutions were not associated with any sublineages to which the strains belong. The analysis of three T-cell epitopes revealed four amino acid differences (in aa positions 305, 315, 342, 348) that were associated with the first or second genogroup.

CONCLUSION

Based on the phylodynamic characteristics and amino acid composition of antigenic determinants, it was concluded that the VP6 protein is highly stable and could potentially be a good model for development of a rotavirus vaccine.

Exploring rotavirus proteome to identify potential B- and T-cell epitope using computational immunoinformatics

Rotavirus is the most common cause of acute gastroenteritis in infants and children worldwide. The functional correlation of B- and T-cells to long-lasting immunity against rotavirus infection in the literature is limited. In this work, a series of computational immuno-informatics approaches were applied and identified 28 linear B-cells, 26 conformational B-cell, 44 T_C cell and 40 T_H cell binding epitopes for structural and non-structural proteins of rotavirus. Further selection of putative B and T cell epitopes in the multi-epitope vaccine construct was carried out based on immunogenicity, conservancy, allergenicity and the helical content of predicted epitopes. An in-silico vaccine constructs was developed using an N-terminal adjuvant (RGD motif) followed by T_C and T_H cell epitopes and B-cell epitope with an appropriate linker. Multi-threading models of multi-epitope vaccine construct with B- and T-cell epitopes were generated and molecular dynamics simulation was performed to determine the stability of designed vaccine. Codon optimized multi-epitope vaccine antigens was expressed and affinity purified using the E. coli expression system. Further the T cell epitope presentation assay using the recombinant multi-epitope constructs and the T cell epitope predicted and identified in this study have not been investigated. Multi-epitope vaccine construct encompassing predicted B- and T-cell epitopes may help to generate long-term immune responses against rotavirus. The computational findings reported in this study may provide information in developing epitope-based vaccine and diagnostic assay for rotavirus-led diarrhea in children's.

Update on rotavirus vaccine underperformance in low- to middle-income countries and next-generation vaccines

In the decade since oral rotavirus vaccines (ORV) were recommended by the World Health Organization for universal inclusion in all national immunization programs, significant yet incomplete progress has been made toward reducing the burden of rotavirus in low- to middle-income countries (LMIC). ORVs continue to demonstrate effectiveness and impact in LMIC, yet numerous factors hinder optimal performance and evaluation of these vaccines. This review will provide an update on ORV performance in LMIC, the increasing body of literature regarding factors that affect ORV response, and the status of newer and next-generation rotavirus vaccines as of early 2020. Fully closing the gap in rotavirus prevention between LMIC and high-income countries will likely require a multifaceted approach accounting for biological and methodological challenges and evaluation and roll-out of newer and next-generation vaccines.

The Science is There: Key Considerations for Stabilizing Viral Vector-Based Covid-19 Vaccines

Once Covid-19 vaccines become available, 5–10 billion vaccine doses should be globally distributed, stored and administered. In this commentary, we discuss how this enormous challenge could be addressed for viral vector-based Covid-19 vaccines by learning from the wealth of formulation development experience gained over the years on stability issues related to live attenuated virus vaccines and viral vector vaccines for other diseases. This experience has led –over time– to major improvements on storage temperature, shelf-life and in-use stability requirements. First, we will cover work on ‘classical’ live attenuated virus vaccines as well as replication competent viral vector vaccines. Subsequently, we address replication deficient viral vector vaccines. Freeze drying and storage at 2–8 °C with a shelf life of years has become the norm. In the case of pandemics with incredibly high and urgent product demands, however, the desire for rapid and convenient distribution chains combined with short end-user storage times require that liquid formulations with shelf lives of months stored at 2–8 °C be considered. In confronting this “perfect storm” of Covid-19 vaccine stability challenges, understanding the many lessons learned from decades of development and manufacturing of live virus-based vaccines is the shortest path for finding promising and rapid solutions.

Maternal antibody interference contributes to reduced rotavirus vaccine efficacy in developing countries

Rotavirus (RV) vaccine efficacy is significantly reduced in lower- and middle-income countries (LMICs) compared to high-income countries. This review summarizes current research into the mechanisms behind this phenomenon, with a particular focus on the evidence that maternal antibody (matAb) interference is a contributing factor to this disparity. All RV vaccines currently in use are orally administered, live-attenuated virus vaccines that replicate in the infant gut, which leaves their efficacy potentially impacted by both placentally transferred immunoglobulin G (IgG) and mucosal IgA Abs conferred via breast milk. Observational studies of cohorts in LMICs demonstrated an inverse correlation between matAb titers, both in serum and breast milk, and infant responses to RV vaccination. However, a causal link between maternal humoral immunity and reduced RV vaccine efficacy in infants has yet to be definitively established, partially due to limitations in current animal models of RV disease. The characteristics of Abs mediating interference and the mechanism(s) involved have yet to be determined, and these may differ from mechanisms of matAb interference for parenterally administered vaccines due to the contribution of mucosal immunity conferred via breast milk. Increased vaccine doses and later age of vaccine administration have been strategies applied to overcome matAb interference, but these approaches are difficult to safely implement in the setting of RV vaccination in LMICs. Ultimately, the development of relevant animal models of matAb interference is needed to determine what alternative approaches or vaccine designs can safely and effectively overcome matAb interference of infant RV vaccination.

Product review of the rotavirus vaccines ROTASIIL, ROTAVAC, and Rotavin-M1

Rotavirus is the leading cause of severe dehydrating gastroenteritis and death due to diarrhea among children under 5, causing over 180,000 under-5 deaths annually. Safe, effective rotavirus vaccines have been available for over a decade and are used in over 98 countries. In addition to the globally available, WHO-prequalified ROTARIX (GSK) and RotaTeq (Merck), several new rotavirus vaccines have attained national licensure - ROTAVAC (Bharat Biotech) and ROTASIIL (Serum Institute of India), licensed and manufactured in India and now WHO-prequalified, and Rotavin-M1 (PolyVac), licensed and manufactured in Vietnam. In this review, we summarize the available clinical trial and post-introduction evidence for these three new orally administered rotavirus vaccines. All three vaccines have demonstrated safety and efficacy against rotavirus diarrhea, although publicly available preclinical data are limited in some cases. This expanding product landscape presents a range of options to optimize immunization programs, and new presentations of each vaccine are currently under development.

Increasing detection of rotavirus G2P[4] strains in Nizhny Novgorod, Russia, between 2016 and 2019

Rotavirus infection is one of the leading causes of acute gastroenteritis in children in their first years of life. We studied the genotypic diversity of rotavirus A (RVA) strains in Nizhny Novgorod, Russia, during the period 2016-19. In total, 4714 samples of faeces from children admitted to the Nizhny Novgorod Hospital for Infectious Diseases with acute gastroenteritis were examined. The share of rotavirus-positive samples was 31.5% in 2016-17. It decreased to 21.6% in 2018-19. In Nizhny Novgorod, all six global types of RVA were detected (G1P[8], G2P[4], G3P[8], G4P[8], G9P[8] and G12P[8]), as well as sporadic samples with genotypes G9P[4], G3P[9], G9P[9], G8P[8], G2P[8], G4P[4], G3P[9]. The fraction of strains with genotype G2P[4] gradually increased from 5.9% in 2016-17 to 39.1% in 2018-19. Simultaneously, the proportion of G9P[8] strains decreased from 63.2% to 27.7% in the same period. Phylogenetic analysis showed that rotaviruses with the G2P[4] genotype carried ubiquitous alleles of the VP7 and VP4 genes during the period of their prevalence: G2-IVa-1 and G2-IVa-3; P[4]-IVa and P[4]-IVb. As rotavirus vaccination is not widely used in the region because it is not included in the national vaccination calendar in Russia so far, the increase in the number of G2P[4] RVA is likely due to natural strain fluctuations.

Technical product attributes in development of an oral enteric vaccine for infants

Development of an oral enteric vaccine for infants is important for Shigella and enterotoxigenic Escherichia coli (ETEC) vaccine development. At a recent workshop titled "Technical Product Attributes in Development of an Oral Enteric Vaccine for Infants," at the 2nd International Vaccines Against Shigella and ETEC Conference (VASE Conference), the preferred product attributes for development were discussed for these vaccines. The aims of this workshop were to identify gaps and gather opinions from key experts from preclinical, process development, manufacturing, regulatory, and clinical areas to fine-tune and refine key target product attributes for infant oral vaccine development. The workshop used some examples of marketed oral infant vaccines to discuss potential improvements that can be made, such as inclusion of preservatives, multidose vials, and antacid buffer presentation (liquid or lyophilized) in novel oral enteric vaccine development.

Effect of change in cell substrate on the critical quality attributes of L-Zagreb Mumps vaccine manufactured using parallel plate bioreactor

Leningrad-Zagreb strain of mumps vaccine virus was grown on two different cell substrates viz. MRC-5 cells and Vero cells besides its original cell substrate i.e. Chicken Embryo Cells. Homogeneous virus pools prepared from each set of experiments were then lyophilized as per standard in-house protocol. Critical Quality Attributes (CQAs) such as the titer of the bulk vaccine and potency and stability of the lyophilized vaccine were then estimated using the CCID₅₀ method to understand the lyophilization losses and thermal losses respectively in the vaccine. Another CQA viz. the genetic homogeneity of the vaccine was also tested using the single base extension method for identifying the nucleotides present at the three known locations of single nucleotide polymorphism (SNP). Comparison of CQA results across different cell substrates indicated encouraging results for Vero cell grown L-Zagreb virus compared to the MRC-5 cells grown L-Zagreb mumps virus. Significant improvement in productivity was also observed in the dynamic culture conditions compared to the static culture conditions. Progressive work in this research area can lead to development of a cGMP manufacturing process for mumps vaccine with easy scale up potential in future.

Current and new rotavirus vaccines

As of 2019, four rotavirus vaccines have been prequalified by the WHO for use worldwide. This review highlights current knowledge regarding rotavirus vaccines available, and provides a brief summary of the rotavirus vaccine pipeline.

Overview of the Development, Impacts, and Challenges of Live-Attenuated Oral Rotavirus Vaccines

Safety, efficacy, and cost-effectiveness are paramount to vaccine development. Following the isolation of rotavirus particles in 1969 and its evidence as an aetiology of severe dehydrating diarrhoea in infants and young children worldwide, the quest to find not only an acceptable and reliable but cost-effective vaccine has continued until now. Four live-attenuated oral rotavirus vaccines (LAORoVs) (Rotarix^®, RotaTeq^®, Rotavac^®, and RotaSIIL^®) have been developed and licensed to be used against all forms of rotavirus-associated infection. The efficacy of these vaccines is more obvious in the high-income countries (HIC) compared with the low- to middle-income countries (LMICs); however, the impact is far exceeding in the low-income countries (LICs). Despite the rotavirus vaccine efficacy and effectiveness, more than 90 countries (mostly Asia, America, and Europe) are yet to implement any of these vaccines. Implementation of these vaccines has continued to suffer a setback in these countries due to the vaccine cost, policy, discharging of strategic preventive measures, and infrastructures. This review reappraises the impacts and effectiveness of the current live-attenuated oral rotavirus vaccines from many representative countries of the globe. It examines the problems associated with the low efficacy of these vaccines and the way forward. Lastly, forefront efforts put forward to develop initial procedures for oral rotavirus vaccines were examined and re-connected to today vaccines.

Rotavirus infection in children in Southeast Asia 2008-2018: disease burden, genotype distribution, seasonality, and vaccination

Background

Rotaviruses (RVs) are recognized as a major cause of acute gastroenteritis (AGE) in infants and young children worldwide. Here we summarize the virology, disease burden, prevalence, distribution of genotypes and seasonality of RVs, and the current status of RV vaccination in Southeast Asia (Cambodia, Indonesia, Lao People’s Democratic Republic, Malaysia, Myanmar, Philippines, Singapore, Thailand, and Vietnam) from 2008 to 2018.

Methods

Rotavirus infection in Children in Southeast Asia countries was assessed using data from Pubmed and Google Scholars. Most countries in Southeast Asia have not yet introduced national RV vaccination programs. We exclude Brunei Darussalam, and Timor Leste because there were no eligible studies identified during that time.

Results

According to the 2008–2018 RV surveillance data for Southeast Asia, 40.78% of all diarrheal disease in children were caused by RV infection, which is still a major cause of morbidity and mortality in children under 5 years old in Southeast Asia. Mortality was inversely related to socioeconomic status. The most predominant genotype distribution of RV changed from G1P[8] and G2P[4] into the rare and unusual genotypes G3P[8], G8P[8], and G9P[8]. Although the predominat strain has changed, but the seasonality of RV infection remains unchanged. One of the best strategies for decreasing the global burden of the disease is the development and implementation of effective vaccines.

Conclusions

The most predominant genotype distribution of RV was changed time by time. Rotavirus vaccine is highly cost effective in Southeast Asian countries because the ratio between cost per disability-adjusted life years (DALY) averted and gross domestic product (GDP) per capita is less than one. These data are important for healthcare practitioners and officials to make appropriate policies and recommendations about RV vaccination.

Rotavirus vaccines in clinical development: Current pipeline and state-of-the-art

Rotavirus (RV) disease is a leading cause of mortality and morbidity, especially in children under 5 years of age. The introduction of the two oral rotavirus vaccines Rotarix^® and RotaTeq^® has shown significant reductions in RV-related mortality, severe RV disease, and hospitalizations. However, some barriers, including a reduced efficacy in low-income countries, safety issues regarding the intussusception risk, age restrictions on vaccine use, the live-attenuated nature itself, and the substantial vaccine costs, currently restrict the full potential of RV disease prevention. Therefore, research is now focusing on the implementation of new oral vaccines and the development of parenteral vaccines to overcome these limits. This review provides an overview of the new rotavirus vaccines in clinical development and the ongoing clinical trials on new RV vaccines in the pediatric age.

The potential role of using vaccine patches to induce immunity: platform and pathways to innovation and commercialization

Introduction: In the last two decades, the evidence related to using vaccine patches with multiple short projections (≤1 mm) to deliver vaccines through the skin increased significantly and demonstrated their potential as an innovative delivery platform.Areas covered: We review the vaccine patch literature published in English as of 1 March 2019, as well as available information from key stakeholders related to vaccine patches as a platform. We identify key research topics related to basic and translational science on skin physical properties and immunobiology, patch development, and vaccine manufacturing.Expert opinion: Currently, vaccine patch developers continue to address some basic science and other platform issues in the context of developing a potential vaccine patch presentation for an existing or new vaccine. Additional clinical data and manufacturing experience could shift the balance toward incentivizing existing vaccine manufactures to further explore the use of vaccine patches to deliver their products. Incentives for innovation of vaccine patches differ for developed and developing countries, which will necessitate different strategies (e.g. public-private partnerships, push, or pull mechanisms) to support the basic and applied research needed to ensure a strong evidence base and to overcome translational barriers for vaccine patches as a delivery platform.

Stability of a monovalent rotavirus vaccine after exposure to different temperatures observed in KwaZulu-Natal, South Africa

Background

Rotavirus infection and its associated hospitalization of children less than 5 years old in middle- and low-income countries remains a public health challenge. We hypothesized that the Rotarix®potency is affected by non-optimal temperatures which translates into reduced vaccine effectiveness in these settings.

Objective

To assess the effect of non-optimal temperatures on the potency of the Rotarix® vaccine in South Africa.

Methods

Rotarix® vaccine was exposed to temperatures reflecting breaches in the cold chain. Vero cells (ATCC CCL-81) grown in a 24-well tissue culture plates were infected with Rotarix® vaccine viruses after exposure to non-optimal temperatures and the potency of the vaccine was determined using the plaque assay.

Results

Exposure of the Rotarix® vaccine to seasonal temperatures in KwaZulu-Natal for 6 hours and to extreme temperatures of 40oC for 72 hours as well as to −20°C and −80°C for 12 hours did not affect the potency of the vaccine beyond its expected standard of >7 x 10⁵ PFU/ml.

Conclusion

This study revealed that the Rotarix® vaccine remains potent even after exposure to non-optimal temperatures. However, this study only explored the effect of a constant ‘adverse’ temperature on vaccine potency and not the effect of temperature fluctuations.

Evidence of reduction of rotavirus diarrheal disease after rotavirus vaccine introduction in national immunization programs in the African countries: Report of the 11th African rotavirus symposium held in Lilongwe, Malawi

The 11th African Rotavirus Symposium was held in Lilongwe, Malawi from May 28th to 30th 2017. Over 270 delegates (73% from Africa) from 40 countries of which 30 (75%) were from African countries attended the symposium. Participants in this symposium included research scientists, clinicians, immunization managers, public health officials, policymakers and vaccine manufacturers. At the time of the symposium, 38 of the 54 (70%) countries in Africa had introduced rotavirus vaccines into their national immunization schedules. Delegates shared progress from rotavirus surveillance and vaccine impact monitoring, demonstrating the impact of the vaccine against rotavirus diarrheal hospitalizations. Data supported the beneficial effect and safety of WHO pre-qualified available vaccines up to 2017 (RotaTeq, Rotarix). This symposium highlighted the dramatic impact of the rotavirus vaccination, called for urgent adoption of these vaccines in remaining countries, particularly those with high disease burden and large birth cohorts (e.g. Nigeria, Democratic Republic of Congo) to attain the full public health benefits of rotavirus vaccination in Africa.

Thermal Stabilization of Viral Vaccines in Low-Cost Sugar Films

Most currently available vaccines, particularly live vaccines, require the cold chain, as vaccine efficacy can be significantly hampered if they are not stored in a temperature range of 2-8 °C at all times. This necessity places a tremendous financial and logistical burden on vaccination programs, particularly in the developing world. The development of thermally stable vaccines can greatly alleviate this problem and, in turn, increase vaccine accessibility worldwide. In this paper, we detail a simple and cost-effective method for stabilizing live vaccines that uses FDA-approved materials. To this end, we dried enveloped DNA (Herpes Simplex Virus type 2) and RNA (Influenza A virus) viral vaccines in a pullulan and trehalose mixture. The results of these studies showed that the live-attenuated HSV-2 vaccine retained its efficacy for at least 2 months of storage at 40 °C, while the inactivated influenza vaccine was able to retain its immunogenicity for at least 3 months of storage at 40 °C. This work presents a simple approach that allows thermo-sensitive vaccines to be converted into thermo-stable vaccines that do not require refrigeration, thus contributing to the improvement of vaccine deployment throughout the world.

Vaccines, inspiring innovation in health

This report covers the topics of pandemics, epidemics and partnerships, including regulatory convergence initiatives, new technologies and novel vaccines, discussed by leading public and private sector stakeholders at the 18th Annual General Meeting (AGM) of the Developing Countries Vaccine Manufacturers' Network (DCVMN). Contributions of Gavi and the vaccine industry from emerging countries to the growing global vaccine market, by improving the supply base from manufacturers in developing countries and contributing to 58% of doses, were highlighted. The Coalition for Epidemic Preparedness Innovations (CEPI), the International Vaccine Institute (IVI) and others reported on new strategies to ensure speedy progress in preclinical and clinical development of innovative vaccines for future MERS, Zika or other outbreak response. Priorities for vaccine stockpiling, to assure readiness during emergencies and to prevent outbreaks due to re-emerging diseases such as yellow fever, cholera and poliomyelitis, were outlined. The role of partnerships in improving global vaccine access, procurement and immunization coverage, and shared concerns were reviewed. The World Health Organization (WHO) and other international collaborating partners provided updates on the Product, Price and Procurement database, the prequalification of vaccines, the control of neglected tropical diseases, particularly the new rabies elimination initiative, and regulatory convergence proposals to accelerate vaccine registration in developing countries. Updates on supply chain innovations and novel vaccine platforms were presented. The discussions enabled members and partners to reflect on efficiency of research & development, supply chain tools and trends in packaging technologies improving delivery of existing vaccines, and allowing a deeper understanding of the current public-health objectives, industry financing, and global policies, required to ensure optimal investments, alignment and stability of vaccine supply in developing countries.

A Phase III open-label, randomized, active controlled clinical study to assess safety, immunogenicity and lot-to-lot consistency of a bovine-human reassortant pentavalent rotavirus vaccine in Indian infants

BACKGROUND

A heat-stable bovine-human rotavirus reassortant pentavalent vaccine (BRV-PV, ROTASIIL®) was developed in India. In this study, the vaccine was tested for safety, immunogenicity and clinical lot-to-lot consistency.

METHODS

This was a Phase III, open label, randomized, equivalence design study. The primary objective was to demonstrate lot-to-lot consistency of BRV-PV. Subjects were randomized into four arms, three arms received Lots A, B, and C of BRV-PV and the control arm, received Rotarix®. Three doses of BRV-PV or two doses of Rotarix® and one dose of placebo were given at 6, 10, and 14 weeks of age. Blood samples were collected four weeks after the third dose to assess rotavirus IgA antibody levels. The three lots of BRV-PV were equivalent if the 95% Confidence Intervals (CIs) of the geometric mean concentration (GMC) ratios were between 0.5 and 2. Solicited reactions were collected by using diary cards.

RESULTS

The study was conducted in 1500 randomized infants, of which 1341 infants completed the study. The IgA GMC ratios among the three lots were around 1 (Lot A versus Lot B: 1.07; Lot A versus Lot C: 1.06; and Lot B versus Lot C: 0.99). The 95% CIs for the GMC ratios were between 0.78 and 1.36. The IgA GMCs were: BRV-PV group 19.16 (95% CI 17.37-21.14) and Rotarix® group 10.92 (95% CI 9.36-12.74) (GMC ratio 1.75; 90% CI 1.51-2.04). Seropositivity rates were 46.98% (95% CI 43.86-50.11) and 31.12% (95% CI 26.17-36.41). The incidence of solicited reactions was comparable across the four arms. No serious adverse events were associated with the study vaccines, except two gastroenteritis events in the BRV-PV groups.

CONCLUSION

Lot-to-lot consistency of BRV-PV was demonstrated in terms of GMC ratios of IgA antibodies. The vaccine safety and immunogenicity profiles were similar to those of Rotarix®. Clinical Trials.Gov [NCT02584816] and Clinical Trial Registry of India [CTRI/2015/07/006034].

Non-interference of Bovine-Human reassortant pentavalent rotavirus vaccine ROTASIIL® with the immunogenicity of infant vaccines in comparison with a licensed rotavirus vaccine

Background

A newly developed bovine-human reassortant pentavalent vaccine (BRV-PV, ROTASIIL®) was tested for its potential effect on the immunogenicity of concomitantly administered EPI vaccines in infants in a randomized controlled study in India.

Methods

In this Phase III, multicenter, open label, randomized, controlled study, three doses of BRV-PV or two doses of Rotarix® and one dose of placebo were given to healthy infants at 6, 10, and 14 weeks of age. Subjects also received three doses of DTwP-HepB-Hib (diphtheria, tetanus, whole-cell pertussis, hepatitis B, and haemophilus influenzae type b conjugate – pentavalent vaccine) and oral polio vaccine concomitantly at 6, 10, and 14 weeks of age and a single dose of inactivated polio vaccine at 14 weeks of age. Blood samples were collected four weeks after the final vaccination to assess immune responses to all the vaccines administered. For diphtheria, tetanus, hepatitis B, Hib, polio type 1, and polio type 3 antibodies, non-interference was to be supported if the lower limit of the two-sided 90% confidence interval (CI) for the seroprotection rate difference for the BRV-PV group minus the Rotarix® group was >10.0%. For pertussis antibodies, non-interference was to be supported if the lower limit of the two-sided 90% CI for the ratio of geometric mean concentrations (GMCs) was >0.5.

Results

A total of 1500 infants were randomized to either BRV-PV (1125 infants) or Rotarix® (375 infants), of which 1341 completed the study as per the protocol. More than 97% of subjects achieved seroprotective antibody titres against diphtheria, tetanus, hepatitis B, Hib, polio type 1, and polio type 3 in both groups. The difference in seroprotection rates between the BRV-PV group and the Rotarix® group for all these antibodies was less than 1%. The ratio of GMCs of anti-pertussis IgG concentrations for the BRV-PV group versus Rotarix® was 1.04 [90% CI: 0.90; 1.19].

Conclusion

BRV-PV does not interfere with the immunogenicity of concomitantly administered routine infants vaccines.

Rational design of heat stable lyophilized rotavirus vaccine formulations

To develop a safe and efficacious heat-stable rotavirus vaccine, new lyophilized formulations were developed using rotavirus serotypes constituting RotaTeq®. A series of formulation compositions, differing in buffering agents, bulking agents, cryoprotectants, amino acids and divalent cations, were screened for their ability to provide stability to rotavirus serotypes during lyophilization and when stored under elevated temperatures for extended periods. Lead formulations and lyophilization cycles were further optimized. Stability profiles of thus optimized formulations showed their ability to retain the potency of rotavirus for > 36 months at 5°C, 20 months at 37°C, and 7 months at 45°C. The heat-stable lyophilized rotavirus formulations developed met the all critical quality attributes for appearance, heat-stability during storage, moisture content as well as pH, viability and stability after reconstitution and has great potential to be used as vaccine candidates for improving access in low-income countries.

Safety of a heat-stable rotavirus vaccine among children in Niger: Data from a phase 3, randomized, double-blind, placebo-controlled trial

BACKGROUND

Rotavirus remains a major cause of diarrhea among children under 5 years of age. The efficacy of RotaSIIL, a pentavalent rotavirus vaccine, was shown in an event-driven trial in Niger. We describe the two-year safety follow-up of this trial.

METHODS

Follow-up of safety outcomes began upon administration of the first dose of RotaSIIL or placebo. Adverse events were followed until 28 days after the third dose, and serious adverse events were followed until 2 years of age. Suspected cases of intussusception were evaluated at first point of contact and then referred to hospital for surgical evaluation. Causes of death were obtained by chart review and verbal autopsy. Passive surveillance was carried out in health centers. Community health workers carried out active surveillance in villages. Between-group differences were evaluated using the chi-squared test and Fisher's exact test.

RESULTS

A total of 4092 children were randomized, and 4086 received at least one dose of RotaSIIL or placebo, constituting the intention-to-treat population, who accrued a total of 7385 child-years of follow-up time. At two years of follow-up, 58 (2.8%) participants who received RotaSIIL and 49 (2.4%) participants who received placebo had died (p = 0.38). Most deaths were due to infectious causes common to the study area. One participant had confirmed intussusception, 542 days after receiving the third dose of RotaSIIL. A total of 395 (19.3%) participants receiving RotaSIIL and 419 (20.5%) participants receiving placebo experienced any serious adverse event (p = 0.36). Most serious adverse events were hospitalizations due to infection (malaria, lower respiratory tract infection and gastroenteritis) or marasmus. Overall, 1474 (72.1%) participants receiving RotaSIIL and 1456 (71.1%) participants receiving placebo had at least one adverse event (p = 0.49) in the follow-up period.

CONCLUSIONS

At two years of follow-up, RotaSIIL was found to be safe.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02145000.

Improving rotavirus vaccine coverage: Can newer-generation and locally produced vaccines help?

There are two internationally available WHO-prequalified oral rotavirus vaccines (Rotarix and RotaTeq), two rotavirus vaccines licensed in India (Rotavac and Rotasiil), one in China (Lanzhou lamb rotavirus vaccine) and one in Vietnam (Rotavin-M1), and several candidates in development. Rotavirus vaccination has been rolled out in Latin American countries and is beginning to be deployed in sub-Saharan African countries but middle- and low-income Asian countries have lagged behind in rotavirus vaccine introduction. We provide a mini-review of the leading newer-generation rotavirus vaccines and compare them with Rotarix and RotaTeq. We discuss how the development and future availability of newer-generation rotavirus vaccines that address the programmatic needs of poorer countries may help scale-up rotavirus vaccination where it is needed.

A randomized Phase III clinical trial to assess the efficacy of a bovine-human reassortant pentavalent rotavirus vaccine in Indian infants

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Pentavalent reassortant rotavirus vaccine was tested for efficacy in infants.

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The vaccine (BRV-PV) showed excellent tolerability and a good safety profile.

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Primary analysis efficacy was 36% against SRVGE and up to 60.5% against VSRVGE.

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The efficacy through 2 years of age was 39.5% (SRVGE) and 54.7% (VSRVGE).

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The intent to treat analyses confirmed all the per protocol analyses.

Rotavirus is the most common cause of moderate-to-severe infant diarrhoea in developing countries, resulting in enormous morbidity, mortality, and economic burden. A bovine-human reassortant pentavalent rotavirus vaccine (BRV-PV) targeting the globally most common strains was developed in India and tested in a randomized, double-blind, placebo-controlled end-point driven Phase III efficacy clinical trial implemented at six sites across India. Infants 6 to 8 weeks of age were randomized (1:1) to receive three oral doses of BRV-PV or placebo at 6, 10, and 14 weeks of age along with routine vaccines. Home visit surveillance was conducted to detect severe rotavirus gastroenteritis (SRVGE) and safety outcomes until the children reached two years of age. A total of 3749 infants received BRV-PV while 3751 received placebo. At the time of the primary end-point (when the minimum number of cases needed for analysis were accrued) the vaccine efficacy against SRVGE was 36% (95% CI 11.7, 53.6, p = 0.0067) in the per protocol (PP) analysis, and 41.9% (95% CI 21.1, 57.3, p = 0.0005) in the intent to treat (ITT) analysis. Vaccine efficacy over the entire follow-up period (until children reached two years of age) was 39.5% (95% CI 26.7, 50, p < 0.0001) in the PP analysis and 38.8% (95% CI, 26.4, 49, p < 0.0001) in the ITT analysis. Vaccine efficacy against the very severe rotavirus cases (VSRVGE, Vesikari score ≥ 16) was 60.5% (95% CI 17.7, 81, p = 0.0131) at the time of the primary analysis and 54.7% (95% CI 29.7, 70.8, p = 0.0004) for the complete follow-period in the PP population. The incidence of solicited, unsolicited, and serious adverse events were similar in both the vaccine and placebo groups. Likewise, the number of intussusceptions and deaths were similar between both groups. Thus, BRV-PV is an effective, well tolerated and safe vaccine in Indian infants. (Trial registration: Clinical Trials.Gov [NCT 02133690] and Clinical Trial Registry of India [CTRI/2013/05/003667]).

Rotavirus Vaccines: a story of success with challenges ahead

Approximately 40 years have passed since the discovery of the rotavirus and 10 years since the introduction and progressive dissemination of rotavirus vaccines worldwide. Currently, 92 countries have introduced rotavirus vaccines into national or subnational programs with evident impact in disease reduction. Two vaccines have been widely used, and four additional vaccines have been licensed and are being used in defined regions. In this context, one main issue that remains unsolved is the lower vaccine efficacy/effectiveness in low-income countries. An additional partially answered issue relates to rotavirus strain circulation in vaccinated populations. These issues are discussed in this review. The most imperative challenge ahead is to fulfill the WHO’s recommendation to introduce rotavirus vaccines in all countries.