In the first study of its kind, after vaccination volunteers will be 'challenged' with paratyphoid to see whether the vaccine can prevent infection.
The Vaccine Against Salmonella Paratyphi (VASP) study will assess the immune response, efficacy and safety of a new vaccine, CVD 1902, against paratyphoid fever (a form of enteric fever similar to typhoid), which is given by mouth as a drink. CVD 1902 was developed by a team of scientists at the Center for Vaccine Development and Global Health (CVD) of the UMSoM. The use of a human challenge model to do this will allow an understanding of the vaccine's effectiveness without having to immunise thousands of people.
A planned sample of up to 76 participants – aged 18 to 55 and in good health – will be randomised to either receive two doses of the new paratyphoid vaccine or a placebo given 14 days apart. All participants will then be challenged with paratyphoid bacteria to see if they are protected against infection.
Following challenge, participants will be monitored closely and treated with antibiotics as soon as they show signs of infection, or after two weeks if they do not show any signs of infection. Results are expected in 2023.