Vaccines act as a cornerstone of public health and form an essential defence against infectious diseases. Vaccines have played a crucial role in eradicating diseases such as smallpox over the past two centuries and have significantly reduced the impact of polio, highlighting their essential role in combating vaccine-preventable infectious diseases. As the most potent defence to prevent the rapid spread of pathogens and mitigate the severity of outbreaks, vaccines effectively manage pandemics. Vaccinology has evolved greatly with time, especially during the recent pandemic. This Edited Volume of the compiled chapters is a thorough exploration of the various aspects of vaccinology, its historical evolution, current advancements, the socioeconomic implications and future directions. The work traces the history of vaccination, from the early variolation techniques to the cutting-edge molecular platforms, illustrating the profound effect of biotechnological progress on vaccine development. COVID-19 pandemic served as a triggering point to showcase the global collective strength and expedited the unprecedented global efforts to design, develop and deploy vaccines in alarming situations. The chapters highlight the rapid evolution of vaccine technologies during the pandemic, with mRNA vaccines emerging as a transformative tool. Many authorised mRNA vaccines to combat SARS-CoV-2 demonstrated remarkable flexibility and efficacy, opening new vistas to address other neglected and reemerging diseases. The technical challenges of mRNA vaccine production including issues surrounding storage, delivery mechanisms, and equitable distribution, especially in low- and middle-income countries are also covered. In addition to the technical advancements, the work examines the challenges in mRNA vaccine production, like the logistics challenges of storage, delivery and equitable distribution in resource-limited areas. Supported by artificial intelligence (AI) and machine learning (ML), reverse vaccinology is revolutionising and accelerating antigen discovery by squeezing the vaccine development timeline. AI and ML facilitate identifying novel antiviral candidates by using bigdata that is essential to timely and effectively counter the mutating pathogens like SARS-CoV-2. Vaccination campaigns protect the vulnerable population by promoting herd immunity and reduce strain on the healthcare systems. The chapters underscore the need for timely vaccine development and deployment as critical to reduce the socioeconomic impact of pandemics and safeguarding the global public health. The chapters collection also delves into the One Health paradigm that emphasises the interconnectedness of human, animal and the environmental health to address zoonotic and reverse zoonotic diseases which are becoming more prevalent. This holistic approach expands vaccination strategies to encompass animals, particularly the disease reservoirs, and stresses the need for a coordinated, equitable vaccination effort for human and animal populations to prevent future pandemics.

The socioeconomic impacts of vaccination are analysed in detail, highlighting its role in reducing the healthcare and hospitalisation costs, and saving precious lives. Despite these advantages, challenges such as vaccine hesitancy, misinformation and inequitable access continue to persist. The chapters explore the disparities between high-income and low- and middle-income countries in vaccine access, advocating for scalable production models and global distribution strategies to ensure broader immunisation coverage. The benefits of booster dose are assessed in light of waning immunity and emerging viral variants. The influence of stimuli like circadian rhythms on vaccine efficacy and the role of boosters in public healthcare strategies are considered crucial in optimising immunisation efforts. Emphasising enhanced immunity and extending protection against severe disease outcomes as necessary, this dedicated chapter discusses the biological and economic implications of booster vaccination. India’s significant contribution to global vaccine diplomacy is highlighted as a key case study. India’s rapid and large-scale vaccine production during the COVID-19 pandemic demonstrated its capacity to greatly influence global healthcare as demonstrated through its vaccine diplomacy. Indian vaccine manufacturers played a vital role in providing affordable and effective vaccines, supporting equitable distribution policies and fostering international cooperation. These efforts underscored India’s strategic position in global vaccine landscape and its commitment to advancing community healthcare initiatives.

This collection of chapters offers a comprehensive understanding of the scientific, technological and socioeconomic dimensions of vaccine development. It presents a narrative of resilience and innovation, illustrating the ability of the global community to respond to emergency health situations while emphasising the importance of continued investment in research, infrastructure, and equitable healthcare practices. This work would serve as a useful resource for researchers, policymakers and healthcare professionals, providing critical insights into the challenges and opportunities in vaccinology and shaping a roadmap to address future global health challenges.

Snehasish Mishra, PhD, MBA, Associate Professor, is a distinguished faculty member at the School of Biotechnology, KIIT Deemed-to-be University, Bhubaneswar, Odisha, India. With over two decades of research and teaching experience, including international exposure, he has made significant contributions to infection biology, public health, microbial technology, limnology, environmental biotechnology, renewable energy, bioprocess engineering and food sciences. Dr. Mishra leads the Government of India's Ministry of New and Renewable Energy (MNRE) sponsored Biogas Development and Training Centre (BDTC) at KIIT Since 2009, focusing on advancing biogas technologies and promoting sustainable energy solutions. Dr. Mishra has authored over 175 publications, including research articles, popular articles and book chapters, in peer-reviewed journals and books of national and international repute. His scholarly works have garnered more than 2000 citations, reflecting the impact and relevance of his research in the scientific community. Beyond his research, Dr. Mishra is actively involved in skill development and livelihood enhancement initiatives for the farming community through biotechnological interventions. He regularly conducts short-term training programmes funded by the Department of Science and Technology (DST), Department of Biotechnology (DBT) and Ministry of Micro, Small and Medium Enterprises (MSME), on sustainable agricultural practices and renewable energy technologies. Dr. Mishra serves as a reviewer and editorial member for several research journals of international standing, contributing to the advancement of scientific knowledge and maintaining the quality of published research. He actively participates in bioentrepreneurship and industry-academia collaborations, bridging the gap between academic research and practical applications. Dr. Mishra received numerous accolades and recognitions through his career, from academies, societies and associations, acknowledging his continued contributions to science and education. He has successfully guided and continues to mentor numerous PhD, MPhil, MTech, and MSc students, fostering the next-generation scientists and researchers.

Puneet Kumar Singh is a researcher at the Bioenergy Lab, School of Biotechnology, KIIT Deemed-to-be University, Bhubaneswar, Odisha, India. Holding a PhD in Biotechnology, his research interests span across microbiology, bioprocess engineering, environmental biotechnology and renewable energy, focusing on waste management and bioenergy generation. A key focus of his work is enhancing biomethanation processes, thermo-alkali combined lignocellulose pretreatments. His research significantly improved biogas yields and provided molecular-level insights, addressing challenges in waste-to-energy conversion and contributing to the development of sustainable energy solutions. His doctoral research centered on circular bioeconomy zero-waste systems, optimising processes to convert organic substrates into renewable energy. Beyond bioenergy, Dr. Singh’s research extends to environmental remediation, human and environmental health, with particular focus on the use of materials and metals. Dr. Singh gained valuable experience through collaborations with national and international laboratories, which have enhanced his expertise in environmental microbiology and bioprocess engineering. His ability to integrate diverse methodologies and technologies reflects his commitment to address global sustainability challenges and ensuring the health and wellbeing of one and all through scientific interventions. Dr. Singh has published over 40 research papers and five book chapters in esteemed international journals and publications. Dr. Singh actively contributes to academic and research development at KIIT Deemed-to-be University. He mentors MTech, MSc and PhD students and supports the Bioenergy Lab’s mission of advancing renewable and sustainable energy technologies.

Ranjan Kumar Mohapatra, an esteemed inorganic chemist specialising in coordination chemistry, works in the Department of Chemistry at the Government College of Engineering, Keonjhar, Odisha, India. He obtained his PhD in 2011 and has since built a remarkable academic and research career. Dr. Mohapatra has published over 300 research and review papers in prestigious national and international journals, 13 books and 25 book chapters, as his significant contributions to the scientific community. He has filed 12 patents, five of which have already been granted, highlighting his focus on practical, innovative solutions. His research interests are broad and interdisciplinary, encompassing bioinorganic chemistry, medicinal chemistry, in silico drug design, public health and infectious diseases. His expertise in in silico methodologies is particularly noteworthy, enabling him to design and optimise potential drug candidates, which contributes to advancements in medicinal chemistry and development of therapeutics. With nearly two decades of teaching and research experience, Dr. Mohapatra has consistently demonstrated academic excellence. He supervises MPhil and PhD students as a mentor of the next generation scientists. His approachable nature and exceptional teaching skills have earned him significant popularity among his students, who greatly benefit from his extensive knowledge and passion. Dr. Mohapatra is listed among the top 2% of global researchers, a testament to the global impact and relevance of his work in the scientific arena.