Advancements in viral vaccine development: from traditional to modern approaches

Advancements in viral vaccine development have revolutionized public health by reducing the burden of infectious diseases worldwide. The development of vaccinology started with Jenner’s smallpox vaccine and Salk’s polio vaccine among other live attenuated and inactivated vaccines before shifting to modern platforms that include subunit, protein-based, and viral vector vaccines as well as messenger RNA (m-RNA) vaccines. Subunit and protein-based vaccines are the ones that protect specific subpopulations and contain low risks; reverse vaccinology, built on genome sequencing and using computational methods for identification of the antigens, helps to cut the time for vaccination development. The COVID-19 experience by itself has shown the feasibility of faster and easily scalable m-RNA development that provides a very strong immunogenicity and safety profile. These advancements are crucial in the fight against new and resurging pathogens, for example, severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), human immunodeficiency virus (HIV), and influenza. They allow the creation of vaccines for highly mutable pathogens or those that evolve strategies to avoid the immune system. Truly innovational approaches in delivering vaccines are lipid nanoparticles, microneedle patches, and thermostability that improve the stability, accessibility, and administration of vaccines in low- and middle-income countries (LMICs). Furthermore, computational immunology, artificial intelligence, and bioinformatics are involved in creating precision vaccines that are likely to suit different populations in society. This review presents solutions to critical barriers including vaccine refusal among the population and unequal distribution systems and transportation requirements along with clinical trial gender bias. Recent strategies employing nanotechnology-based delivery methods and universal vaccines receive assessment regarding their solutions to present challenges. The need for joint public-private collaborations combined with strong health programs and systematic research investments stands essential for developing extensive scalable vaccination strategies. These findings present a detailed guide for improving both the effectiveness and accessibility of vaccines as well as readiness against current and future viral infections.