Salmonella Typhi Vi O-Acetyl Pectin-rEPA Conjugate Vaccine
Status:
Completed
Trial end date:
2008-09-17
Target enrollment:
Participant gender:
Summary
This study will evaluate a new (conjugate) vaccine for typhoid fever, which remains a serious
disease especially difficult to treat in developing countries. Salmonella typhi, the bacteria
causing typhoid fever, have become resistant to several antibiotics increasing the difficulty
of treating the disease. The disease may have serious complications effecting bones, brain,
and intestines, with permanent injury or death. Methods to control typhoid fever, such as a
sanitary water and food supply, along with effective sewage treatment, are not likely to be
available soon in those countries.
NIH scientists developed a vaccine called Vi, made of a polysaccharide (a chain of linked
sugars) from the surface of Salmonella typhi, the bacteria that cause typhoid fever. It has
been approved by the World Health Organization and is licensed in 94 countries. It is
effective in adults but not in young children. Clinical trials have shown that chemically
binding the Vi to a protein to form a "conjugate vaccine" has improved and extended its
efficacy to children (conjugate vaccines to other bacteria, notably meningitis causing
bacteria have been used extensively and successfully). Now NIH scientists have developed
another vaccine for typhoid fever - using a polysaccharide from fruit, known as pectin. The
pectin has been chemically treated so that it resembles Vi. The treated pectin, O-acetyl
pectin, is bound to a protein; exoprotein A, (rEPA). The result is a conjugate, as was formed
for Vi. Similarly to the Vi conjugate it induces antibodies against Salmonella typhi in
laboratory animals. If the O-acetyl pectin conjugate proves successful, it will be evaluated
in children ages 5 to 14 years old and in infants, toward using it with routine vaccines for
infants.
Volunteers ages 18 to 45 who do not have an allergy to fruit pectin and who have not been
vaccinated against nor had typhoid fever within the last 5 years may be eligible for this
study.
Volunteers will undergo several tests at their first visit to the clinic for this study. A
blood sample (about 2/3 of an ounce) will be taken to test for HIV, hepatitis B and C,
complete blood count, liver functions, blood chemistry and pregnancy in women of childbearing
age. The blood sample will also be tested for antibodies to Vi, rEPA (the protein of the
conjugate), and pectin. There will also be a urine collection for testing. If the laboratory
tests are acceptable, volunteers will be asked to return to the clinic on a...
Phase:
Phase 1
Details
Lead Sponsor:
Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)