Comparison of anti-Vi IgG responses between two clinical studies of typhoid Vi conjugate vaccines (Vi-DT vs Vi-TT)

by Eun Young Lee, Ju Yeon Park, Deok-Ryun Kim, Manki Song, Sushant Sahastrabuddhe, Hun Kim, Yun Chon, Jae Seung YangSalmonella enterica serovar Typhi (S. Typhi) is a causative agent for typhoid fever and especially critical in developing countries. Although clinical studies for various typhoid conjugate vaccines (TCVs) have been performed, there are no comparative data on the immune responses of vaccines due to lack of harmonization of the serological assay. Recently, Typbar-TCV (Vi-TT) was prequalified by WHO and recommended for vaccination in endemic areas. Forty-eight serum samples were selected from a recent Vi-DT phase 1 study based on age cohort and anti-Vi IgG levels using an in-house ELISA. Anti-Vi IgG titers of 48 sera were also determined by Vacczyme ELISA, used in a Vi-TT phase 3 trial. A good correlation between the two assays was observed when the anti-Vi IgG titer was determined using Vacczyme ELISA based on the Vi-IgGR1,2011, U.S. reference reagent (Pearson correlation coefficient (r) = 0.991,P

Source: PLoS Neglected Tropical Diseases - March 22, 2020 Category: Tropical Medicine Authors: Eun Young Lee Source Type: research