Parenteral administration of vaccines has been a highly effective strategy for preventing and controlling infectious diseases. Parenteral vaccines are administered through routes other than the gastrointestinal tract, such as intramuscular, subcutaneous, or intradermal injections. These routes offer several advantages, including the rapid and efficient delivery of antigens to the immune system, induction of robust immune responses, and enhanced vaccine stability. Moreover, parenteral vaccines can be formulated with adjuvants to further enhance their immunogenicity. Recent advancements in parenteral vaccine development have focused on several key areas. First, there has been significant progress in the design and formulation of novel antigen delivery systems, such as liposomes, virus-like particles, and nanoparticle-based carriers. These systems offer improved antigen stability, controlled release, and targeted delivery to specific immune cells. Second, advances in recombinant DNA technology have enabled the production of highly purified and well-characterized antigens, improving the safety and efficacy of parenteral vaccines. Third, the development of novel adjuvants, including toll-like receptor agonists and nanoparticle-based adjuvants, has facilitated the modulation of immune responses and the induction of long-lasting immunity. However, parenteral vaccine development also faces several challenges. Vaccine formulation and stability are critical factors, as certain antigens may degrade or lose potency during storage and transportation. Additionally, the choice of adjuvants requires careful consideration, as they need to elicit robust immune responses without causing adverse reactions. Furthermore, the high cost and complex manufacturing processes associated with parenteral vaccines can limit their accessibility, particularly in resource-limited settings. This chapter provides an overview of parenteral vaccine development, highlighting recent advancements and addressing the challenges associated with this approach.

Vaccines against coronavirus disease 2019 (COVID-19) have been discovered within a very small duration of time as compared to the traditional way for the development of vaccines, which raised the question about the safety and efficacy of the approved vaccines. The purpose of this study is to look at the effectiveness and safety of vaccine platforms against the incidence of COVID-19. The literature search was performed on PubMed/Medline, Cochrane, and clinical databases for studies published between 1 January 2020 and 19 February 2022. Preferred Reporting Items for Systemic Review and Meta-Analysis Statement guidelines were followed. Among 284 articles received by keywords, a total of 11 studies were eligible according to the inclusion and exclusion criteria (studies in special populations, e.g., pregnant women, paediatric patients, editorials, case reports, review articles, preclinical and in vitro studies) of the study. A total of 247,186 participants were considered for randomisation at baseline, among them, 129,572 (52.42%) were provided with vaccine (Intervention group) and 117,614 (47.58%) with the placebo (Control group). A pooled fold change estimation of 0.19 (95% CI: 0.12-0.31, p < 0.0001) showed significant protection against the incidence of COVID-19 in the vaccines received group versus the placebo group. mRNA based, inactivated vaccines and non-replicating viral vector-based vaccines showed significantly protection against the incidence of COVID-19 compared to placebo with pooled fold change estimation was 0.08 (95% CI: 0.06-0.10), 0.20 (95% CI: 0.14-0.29) and 0.36 (95% CI: 0.28-0.46), respectively. Injection site discomfort and fatigue were the most common side effect observed in mRNA, non-replicating viral vector, inactivated, and protein subunit-based vaccines. All the approved vaccines were found safe and efficacious but mRNA-based vaccines were found to be more efficacious against SARS-CoV-2 than other platforms.

The coronavirus disease (COVID-19) breakout had an unimaginable worldwide effect in the 21st century, claiming millions of lives and putting a huge burden on the global economy. The potential developments in vaccine technologies following the determination of the genetic sequence of SARS-CoV-2 and the increasing global efforts to bring potential vaccines and therapeutics into the market for emergency use have provided a small bright spot to this tragic event. Several intriguing vaccine candidates have been developed using recombinant technology, genetic engineering, and other vaccine development technologies. In the last decade, a vast amount of the vaccine development process has diversified towards the usage of viral vector-based vaccines. The immune response elicited by such vaccines is comparatively higher than other approved vaccine candidates that require a booster dose to provide sufficient immune protection. The non-replicating adenoviral vectors are promising vaccine carriers for infectious diseases due to better yield, cGMP-friendly manufacturing processes, safety, better efficacy, manageable shipping, and storage procedures. As of April 2022, the WHO has approved a total of 10 vaccines around the world for COVID-19 (33 vaccines approved by at least one country), among which three candidates are adenoviral vector-based vaccines. This review sheds light on the developmental summary of all the adenoviral vector-based vaccines that are under emergency use authorization (EUA) or in the different stages of development for COVID-19 management.

Dengue fever is a flu-like ailment propagated by female mosquitos of the Aedes aegypti species. It is also known as dandaka jwara in Ayurveda. It is most common in the world's subtropical and tropical climate zones. Vomiting, severe headache, nausea, rashes, joint pain, pain behind the eyes, muscle pain, and swollen glands are all common dengue symptoms. If not handled promptly, these symptoms can lead to more severe issues such as exhaustion, blood in the vomit, continuous vomiting, bleeding gums, restlessness, severe abdominal pain, and rapid bleeding. Because there is no specific medication for dengue fever, the disease is treated by eliminating and managing the symptoms. Fortunately, there are a variety of ayurvedic remedies (like Carica papaya L., Cissampelos pareira L., etc) that can help to tackle the same by strengthening the immune system and controlling hyperthermia. This review article provides a comprehensive overview of dengue virus infections, clinical symptoms, diagnosis, mitigation, and treatments, focusing on ayurvedic and herbal remedies.