PAiNTS
Research type
Research Study
Full title
Protection Against invasive NTS Disease (PAiNTS) Identifying correlates of protection and thresholds of protective immunity using a Salmonella Typhimurium challenge-rechallenge model
IRAS ID
344015
Contact name
Malick M Gibani
Contact email
Sponsor organisation
Imperial College London
ISRCTN Number
ISRCTN69516953
Duration of Study in the UK
2 years, 6 months, 1 days
Research summary
This protocol outlines the protocol for a human infection challenge and re-challenge study investigating Salmonella Typhimurium, a type of non-typhoidal Salmonella (NTS). NTS typically causes gastroenteritis—diarrhoea, stomach pain, and fever—that resolve within a few days in most healthy individuals. However, in vulnerable populations (e.g. those with HIV, malaria, sickle cell disease, or malnutrition), it can become invasive (iNTS), spreading beyond the gut and posing serious health risks.
iNTS is a major public health concern, especially in sub-Saharan Africa, affecting over half a million people annually—primarily young children under five, many of whom are malnourished or have coexisting health conditions. Our research focuses on finding ways to prevent this disease, including through vaccine development.
This study, known as a "challenge and re-challenge" study, involves participants ingesting a specific dose of Salmonella Typhimurium under medical supervision. Several months later, they will be exposed to the bacteria a second time. The goal is to understand how the immune system develops memory to protect against repeated NTS infections, which can inform vaccine strategies aimed at mimicking natural immunity.
In practice, participants will drink a solution containing live Salmonella bacteria while being closely monitored. They will stay in the hospital for the first 5 to 7 days for observation, followed by close monitoring over week. If participants develop symptoms of a systemic infection (such as fever or bacteria in the blood), severe gastroenteritis they will receive antibiotics.
Our recent first-in-human study confirmed the safety profile and identified the optimal dose that induces symptoms in about 60% of participants. This study will evaluate whether initial exposure provides immunity to a subsequent exposure.
The study lasts approximately 6–9 months. Each participant will:
• Attend eight scheduled outpatient visits.
• Spend a total of 14 days in hospital quarantine.
• Receive 12 daily telephone calls after discharge.
• Additional visits may be arranged for safety reasons.REC name
London - Riverside Research Ethics Committee
REC reference
26/LO/0316
Date of REC Opinion
20 Apr 2026
REC opinion
Favourable Opinion