The advances of the Chinese Brucella suis strain 2 vaccine

Brucellosis, a worldwide crucial zoonotic disease, poses global socioeconomic risks to the system by threatening human health and animal reproduction. In recent years, with the increase of animal husbandry, animal brucellosis has become a remarkable health issue in China. To prevent and control the spread of brucellosis, Brucella suis live strain S2 vaccine has been licensed as a multivalent vaccine against the three major zoonotic Brucella species, for example, Brucella melitensis (small ruminants), Brucella abortus (bovids), and B. suis (swine). Following this process, the country enforced control measures based upon B. suis S2 vaccination, which reduced the disease burden in 2022 to 0.66% in the livestock population. The aim of this paper is to review and discuss the biological properties of the S2 vaccine and its wide use in vaccination programs of China, highlighting oral vaccination advantages, validation, and standardization of this vaccine as well as the progress of the S2 vaccination program achieved in the national control of the three zoonotic Brucella species.