Live vector vaccines are genetically engineered vaccinations that express protective immune-related antigens and transfer them to the colon via non-pathogenic viruses or bacteria. This produces system immunity and intestinal mucosal immune responses. These vaccines provide several advantages, including as low manufacturing costs, reduced pathogenicity risk, and efficient cellular and humoral immunization. Additionally, they may be used to prevent several illnesses with a single needle, which facilitates the creation of numerous vaccinations. One of the important biological factors is gut microbiota; imbalances in the composition of the gut microbiota, called dysbiosis, can cause several immune disorders by activating the adaptive immune system and preventing the body from responding adequately to vaccinations; bacteria used in probiotics are frequently members of the gut microbiota, which has health benefits for the host. Probiotics as live vaccination carriers to improve immunity and improve intestinal nutrition absorption. While live viral vector vaccines combine attenuated strains and exogenous antigens to generate a new recombinant virus, recombinant live vector vaccines including Lactococcus lactis and B. subtilis can trigger a protective immune response in the host. Baculovirus (BmNPV) and IHNV can also be used as vaccine carriers to induce effective immune protection. Live vector vaccinations can offer certain disadvantages, though, including the possibility of dangerous germs and long-term immunity, which might make the body tolerant to generating antigens and weaken the immune system. Improved immunization techniques and vector selection are required to maximize the protective impact of live vector vaccinations.
