Investigating Enteric Fever - Rechallenge

You are invited to take part in a study investigating enteric fever as you have previously taken part in a Typhoid or Paratyphoid trial run by the Oxford Vaccine Group.  This new study will look at how people who have previously been exposed to Salmonella Typhi or Salmonella Paratyphi respond to repeat infection. The maximum study participation time is 15 months.

Salmonella Typhi and Salmonella Paratyphi cause infections known as enteric fever, which is becoming an increasing problem in developing countries, particularly in Asia.  Although rare in the UK it can be picked up by travelers to these countries. Enteric fever is responsible for over 30 million infections each year, mostly affecting children.  Although the disease can be treated with antibiotics and is preventable with access to clean water and sanitation facilities, there are still many deaths each year. A vaccine for Salmonella Typhi does exist but provides limited protection against infection. There is no licensed vaccine to protect against Salmonella Paratyphi.

Our study is a part of a new effort to find better ways of preventing and diagnosing enteric fever. We are aiming to advance the scientific knowledge of enteric fever and the effect this illness has on the human immune system. We hope that this knowledge will help us better understand enteric fever, develop new diagnostic tests, and help develop new vaccines against S. Typhi and S. Paratyphi in the future. It is thought that people who have repeated enteric fever, do develop some level of immunity to further infection.

We are looking for healthy volunteers to swallow a drink containing either Salmonella Typhi or Salmonella Paratyphi. In addition we ask volunteers to have two endoscopies (a camera looking down into the stomach and small intestine) and have biopsies of the gut lining taken. This is to answer questions on how the bacteria cause illness and why some people are protected and others become unwell. Some people will develop enteric fever and they will be treated immediately with effective antibiotics. Those who do not develop enteric fever two weeks after swallowing the bacteria will still receive a full course of antibiotics, even if they develop no symptoms.

Volunteers may also be asked to participate in optional additional tests such as a video capsule endoscopy (swallowing a camera the size of a vitamin pill until it is passed in the stool) or a ‘string test’  (swallowing a capsule attached to a long string, then later withdrawing the string and collecting the gut liquid).

Volunteers would need to be available for an intensive period of four weeks where the participants would need to attend daily visits with study doctors and nurses for two weeks, take a two week course of antibiotics, and remain in contact with the study team. They would also need to be available for an endoscopy (a day procedure) about a month before and after they ingest the drink containing the bacteria. Visits will occur either at the Centre for Clinical Vaccinology and Tropical Medicine (at the Churchill Hospital site) or at the Endoscopy Unit, John Radcliff Hospital.

This study is being run by the Oxford Vaccine Group, part of the University of Oxford and is funded by the Medical Research Council.

  • If you are aged 18 to 60 years old and in good health you may be eligible to take part in the study.
  • We will provide reimbursement for your time, inconvenience and travel.

Before you decide whether you would like to take part, it is important for you to understand exactly what the study is about and what participation would involve.

If you are interested in finding out more, please read the Study Information Booklet

If you would like any further information regarding the study please contact us on:

Email info@ovg.ox.ac.uk, Tel: 01865 611400

Many thanks,

The Oxford Vaccine Group

Study reference: 2014/01

Ethics reference: 14/SC/1204

: