The production of vaccines requires constant improvement of methods and tools, revision and modernization of the current technology with the aim to improve quality of the product made for the benefit of public health. The purposяe of this work was to improve the process of production of polysaccharide polyribosyl ribitol phosphate (PRP), which is the active agent of Haemophilus influenzae type b (Hib) vaccines. We investigated how PRP yield depends on the following factors: concentration of dissolved oxygen in the culture liquid, glucose concentration control method applied in cultivation, source of protein for the producer microorganism, stability of the polysaccharide at the culture liquid inactivation stage. As a result, we managed to increase the PRP yield in the culture liquid by 10%, ensured a 25% boost of the biomass accumulation rate during cultivation in the fermenter and reduced the cultivation time by 6.5 hours. The PRP loss rate at the culture liquid inactivation stage was reduced by 80%. Relying on the patented composition, we invented a new composition of the nutrient medium that meets the current regulatory requirements.