Indian J Med Res
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Review
Typhoid & paratyphoid vaccine development in the laboratory: a review & in-country experience.
Enteric fever is caused by the infection of Gram-negative bacteria, Salmonella enterica serovar Typhi and Salmonella enterica serovar Paratyphi (S. Paratyphi) A, B and C, through contaminated food and water. The disease almost exclusively affects the populations living in low- and middle-income countries, with the World Health Organization Southeast Asian Region (WHO SEAR) having the highest endemicity. ⋯ Furthermore, typhoid vaccines with a wider coverage, including additional efficacy against Salmonella Paratyphi A and B and preferably the non-typhoidal Salmonella (NTS) serovars, for which no vaccines are currently available would be more desirable. We have developed several subunit vaccine candidates containing the glycoconjugates of the surface polysaccharides of typhoidal and non-typhoidal Salmonellae and an intrinsic Salmonella protein that functions as both antigen and adjuvant. We also developed a novel mouse model of oral Salmonella Typhi infection to test the candidate vaccines, which demonstrated broad protective efficacy against Salmonella spp. through the induction of humoral and cell-mediated immunity as well as memory response.
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Background & objectives The Pneumococcal vaccines were introduced under the Universal Immunization Programme (UIP) in 2021 in India. Drawing from the collective experience of various nations, it is anticipated that there will be a substantial shift in serotype patterns following the introduction of this vaccine. The available data is limited to years until 2018 when the vaccine was introduced in only five States. ⋯ The majority of the 19F and 19A isolates (89.7% and 80%, respectively) were multidrug resistant in the post-vaccine era. Interpretation & conclusions Introducing pneumococcal vaccination reduced the burden of many vaccine serotypes, while the burden of non-vaccine serotypes slightly increased. Most of the vaccine serotypes (like 19F and 19A) that persisted in the post-vaccine era were drug resistant.
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Leishmaniasis is a parasitic disease caused by various species of the Leishmania parasite, manifesting in visceral (VL), cutaneous (CL), and mucocutaneous (MCL) forms. To combat this debilitating disease, various vaccines candidates including proteins, DNA, vectors, adjuvants, and recombinant whole parasites have been developed and tested experimentally and preclinically against several Leishmania species. Some vaccines have already entered human clinical trials. ⋯ This review examines all efforts to develop recombinant vaccines against the parasite, analyzing successes including commercially available canine vaccines and the overall challenges faced in the quest to eradicate the disease. Additionally, recent advances in vaccine delivery systems, such as viral vectors and non-pathogenic bacteria, offer promising avenues to enhance immunogenicity and improve the targeted delivery of antigens, potentially leading to more effective and long-lasting immune responses. By understanding past and current efforts, future strategies can be refined to create more effective vaccines and ultimately control or eradicate this parasitic disease.