Shifting Enteric Fever Epidemiology in Children in Nepal: Is the Burden of Salmonella Paratyphi on the Rise?

Nepal has a high burden of enteric fevers. An observational study conducted in a tertiary-level hospital in Nepal over 11 years (2014-2024), reviewing hospital records of all blood culture-positive cases of Salmonella Typhi and Paratyphi in children, showed a gradual decline in blood culture-positive enteric fever cases with year-to-year variability. Typhoid conjugate vaccine (TCV) was introduced into the national immunisation schedule of Nepal in 2022. We observed that the proportion of Salmonella Paratyphi cases has increased in the post-typhoid conjugate vaccine years compared with the pre-typhoid conjugate vaccine period. A slight rise in hospitalisation rates for blood culture-positive paratyphoid infections has also been observed in the post-typhoid conjugate vaccine period. These findings underscore the importance of continued surveillance and call for further evaluation of the potential shift in enteric fever epidemiology. The development of effective vaccines targeting both typhoid and paratyphoid remains crucial for comprehensive disease control.