View clinical trials related to Typhoid Fever.
Filter by:This trial is aimed to evaluate the safety and immunogenicity profiles of three formulations of Vi-CRM197 conjugate vaccine against S. Typhi in healthy human adults in comparison with the currently licensed Vi polysaccharide vaccine
This trial is aimed to evaluate the safety and immunogenicity profiles of a new Vi-CRM197 conjugate vaccine against S. Typhi in healthy human adults in comparison with the currently licensed Vi polysaccharide vaccine.
The efficacy and immunogenicity of enteric vaccines have generally been found to be lower in children in the developed than in the developing countries. This has been observed with vaccines against cholera rotavirus, ETEC and typhoid vaccines. There are a number of factors that may contribute to such differences in vaccine "take rates" in children, e.g. breast feeding and nutritional status of the children might influence their immunogenicity and efficacy. Thus, breast feeding of newborn and young infants may adversely influence the immune response to vaccination, which might have more pronounced effect in developing than in developed countries. Breastfeeding has also been shown to interfere with the serum immune responses to rotavirus vaccine although this effect could be overcome by administering three rather than one dose of the oral rotavirus vaccine. Our recent study of Dukoral in Bangladeshi children aged 18 months or younger has shown that the response rates and the magnitude of responses improved when breast milk was temporarily withheld . Thus, administration of vaccines may have to be adjusted when given to breast fed children. Another factor that may affect the immunogenicity is the effect of zinc. Previous studies have shown that zinc enhances the immune response to cholera vaccine in participants > 2 years of age , a recent study also observed a similar effect in infants. In this research project, we plan to study a number of different factors that might influence the immunogenicity of the two licensed oral model vaccines, specifically the inactivated killed oral cholera vaccine, Dukoral, and the live oral typhoid vaccine, Ty21a. We will also identify strategies that might improve the immunogenicity of the vaccines. The main objective of our study is to identify immunization regimens that may improve the immunogenicity of the vaccines in young children, which could be subsequently in field trials in Bangladesh and other developing countries. Specifically, we will determine if: (i) interventions identified to enhance immune responses to Dukoral, including zinc supplementation, could also enhance the immune responses to Ty21a; (ii) these two vaccines are able to induce both acute and memory B and T cell responses, (iii) treatment with antiparasitic drugs prior to immunization could modulate the immune responses to cholera and typhoid vaccines; and (iv) examine if arsenic exerts a suppressive effect on the immunogenicity of these vaccines.
This study is to investigate the safety, tolerability and immunogenicity of the typhoid fever vaccine candidate M01ZH09 manufactured at commercial scale, at a new manufacturing facility. The vaccine will be delivered as a single oral dose to healthy, typhoid vaccine-naïve adults.
The purpose of this trial is to examine the safety and immunogenicity of Ty800 oral vaccine in healthy adult subjects.
Typhoid fever remains an important cause of morbidity and mortality in the developing world. It is estimated that more than 16 million cases and about 600,000 deaths occur annually, most of which occur in Southeast Asia and Africa. Ingestion of food or water contaminated by acutely infected persons or chronic carriers is the most common form of transmission. As a result, typhoid fever is prevalent where unsafe drinking water or contaminated food is common. Typhoid fever is highly endemic in Vietnam, especially in the southern provinces and is a significant disease in both preschool and school-aged children. Data from Dong Thap Provincial Hospital, Mekong delta region showed that among 3,934 hospitalized typhoid fever cases from 1990 to 1995, 4.2% had complications and 0.8% died. Typhoid fever has become difficult and expensive to treat. About 90% of Salmonella typhi isolates are of multidrug-resistant (resistant to chloramphenicol, ampicillin, and trimethoprim-sulfamethoxazole) and 76% of isolates showed reduced susceptibility to fluoroquinolones. Isolates with full fluoroquinolone or extended spectrum cephalosporin resistance have not yet reported in Vietnam but occur sporadically in the Indian subcontinent. If they become widespread, alternative treatment options will be limited. The improvement of sanitation, provision of safe water and elimination of chronic carriage is not expected to be achieved quickly. Accordingly, vaccination against typhoid fever is increasingly important national public health priority.
The purpose of this study is to evaluate the safety, immunogenicity, and compatibility of our Vi-rEPA conjugate administered to infants with their routine vaccinations. We propose to recruit 300 full term healthy newborns in Vietnam and randomly divide them to receive Vi-rEPA plus DTP, Hib-TT (not yet used in Vietnam) plus DTP, or DTP alone. Consent is obtained following interviews of mothers during prenatal visits, or after delivery. All vaccines will be administered at 2, 4, and 6 months. A booster of Vi-rEPA or Hib-TT conjugate will be administered at 12 months of age and reactions monitored at 6, 24 and 48 hours after each injection. Maternal and cord blood samples are collected during labor and at delivery. Blood will be taken at 7, and 12 months of age from all study infants and at 13 months from infants injected with Vi-rEPA or with Hib-TT at 12 months. The blood samples will be assayed for Vi, Hib, diphtheria, tetanus and pertussis antibodies. The levels of serum IgG anti-Vi elicited by Vi-rEPA administered to infants by the above schedule will be compared to those elicited by this vaccine in 2 to 5 year-olds in the efficacy trial conducted in Dong Thap Province, Vietnam.
The purpose of this research study is to see if giving a typhoid vaccine by mouth (an experimental vaccine, CVD 909) before giving a vaccine shot (Typhim Vi) will result in a better immune response than giving Typhim Vi vaccine by itself. Another purpose is to see whether CVD 909 is safe. Typhim Vi has been shown to be safe and effective in preventing typhoid fever in older children and adults, but it does not work in children under age 2. Scientists at the University of Maryland think that young children could respond to Typhim Vi if they were given a dose of the other typhoid vaccine by mouth before they are given the Typhim Vi shot. Twenty-eight healthy adult volunteers, ages 18-40 years, will take part in this study. Study participation will last for up to 63 weeks, but most of the study visits will be in the first 6 weeks. Blood samples will be collected approximately 13 times. Four stool samples will be collected. Some volunteers may be followed for an additional 4 years.
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...
The purpose of this research study is to determine whether a new vaccine for typhoid fever is safe and effective. This study will also look at what effects (good and bad) this new vaccine, Ty800, has on the volunteers. The study will determine the highest dose of Ty800 that can be given without causing severe side effects. About 54 healthy males and females, ages 18-45 inclusive, in the Cincinnati metropolitan area will be enrolled in this study. They will be in the study for approximately 7 months, which includes a one month screening period, study product administration on Day 0, a 10-day hospital stay, an outpatient period on Days 9-28 with 4 follow-up visits, and safety follow-up phone calls at 2 and 6 months after hospital discharge. Researchers hope that this trial will help produce a vaccine that combines a high level of durable protective immunity with simplicity of administration and minimal reaction to the vaccine.