typhoid + paratyphoid A

A **bivalent typhoid + paratyphoid A conjugate vaccine** is an investigational vaccine candidate designed to provide immunization against both **Salmonella Typhi** and **Salmonella Paratyphi A**, the causes of typhoid and paratyphoid fever. It typically employs conjugation of the **Vi polysaccharide (from S. Typhi)** and **O:2 antigen (from S. Paratyphi A)** to protein carriers (such as tetanus toxoid), optionally formulated with aluminum-based adjuvant. Its mechanism is to stimulate the immune system to produce antibodies targeting the surface polysaccharide antigens of both bacteria, preventing their ability to cause invasive disease[1][4]. Current development prioritizes these bivalent vaccines because of their capacity to address enteric fever in regions endemic for both pathogens, and several conjugate formulations are in clinical phases. Primary indication is the **prevention of enteric fever (typhoid and paratyphoid A fevers)**.

Other names

bivalent typhoid-paratyphoid A conjugate vaccinetyphoid-paratyphoid A vaccine