A Phase II, Multicentre, Double-blind, Randomised, Controlled Study of a Bivalent Conjugate Vaccine against Salmonella enterica serovar Typhi and Paratyphi A to evaluate the Efficacy, Immunogenicity and Safety using a Human Challenge Model of Paratyphoid A Infection. (BiVISTA)

Research summary

This is a multicentre,double blinded,randomised,active-controlled study of a novel vaccine SII-TCV(B) against typhoid and paratyphoid A infection,using a healthy adult participant controlled human challenge model of paratyphoid A infection compared with a licensed Vi-polysaccharide vaccine against typhoid infection (Typhim Vi). The aim is to assess the efficacy of SII-TCV(B) against S. Paratyphi A using the challenge model and to demonstrate the non-inferiority of the immune response to the S. Typhi component of SII-TCV(B),when compared to Typhim Vi. In total,192 participants will be randomised in a 1:1 ratio to receive a single dose of IMP: 0.5 mL of either SII-TCV(B) or Typhim Vi (96 participants per allocation arm) via intramuscular route. Both participants and investigators,including outcome assessors and data analysts,are blinded to the allocation arm. Twenty-eight days after their IMP administration,participants will be orally challenged with S. Paratyphi A (strain NVGH308) at a dose of 1-5 x 10^3 CFU suspended in 30ml of sodium bicarbonate,the dose previously established to give a desired clinical/laboratory ‘attack’ rate of approximately 58% of paratyphoid A infection by day 14 post-challenge (as per prior OVG S. Paratyphi A studies OVG 2013/07,REC Ref: 14/SC/0004 and OVG 2014/01,REC Ref: 14/SC/1204).

Principal Investigator

Dr Brian Angus

Contact us

Email: emergency.research@oxnet.nhs.uk

IRAS number

1007772