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Protocol Number: 06-CH-0070 
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 subsequent day for a history of recent infections and a physical examination. Then 0.5 mL of vaccine will be injected into the volunteer's upper arm. Clinic health staff will take the volunteers' temperature and examine them 30 minutes later. At 6, 24, and 48 hours later, volunteers will take their own temperatures and examine the injection sites for redness, swelling, or both. Each will be required to record that information on forms provided to them and to mail them to the study center within 1 week. The health staff will explain how to measure the reaction site. If volunteers have a fever above 38.5 C (101.3 F) or if there is swelling greater than 2.5 cm (1 inch) in diameter, or if they feel they need a consultation regarding the vaccination they should return to the clinic, where their temperatures will again be taken and the injection site inspected. A doctor will examine them and make recommendations as necessary. The volunteers will return to the clinic 6 weeks and 26 weeks later. They will be asked about their health, if they had fever, or if they were admitted to a hospital during that period. At each visit, a small amount of blood (about 1/3 of an ounce) will be collected. Side effects from the vaccine, other than potentially slight pain, redness, and swelling, or a mild fever for 1 to 2 days, are not expected. The vaccine does not contain bacteria and typhoid fever cannot be caused by it. Rare reactions can be treated at the Clinical Center. Predicted benefits to participation in the study are that volunteers will have a long-lived increase in antibodies to typhoid fever. Participants will be paid for each clinic visit, with the payment amount guided by NIH policies.
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National Institutes of Health Clinical Center