SK Bioscience Co. Ltd. of Seongnam-si, South Korea, gained the World Health Organization’s (WHO) prequalification certification for typhoid conjugate vaccine, Skytyphoid (NBP-618), on Feb. 23. Skytyphoid conjugates a polysaccharide of typhoid bacteria, which serves as an antigen, to a diphtheria toxin protein called diphtheria toxoid that acts as a carrier.