Vivotif (Typhoid Vaccine Live Oral Ty21a) - Summary

VIVOTIF SUMMARY

Vivotif® (Typhoid Vaccine Live Oral Ty21a) is a live attenuated vaccine for oral administration only. The vaccine contains the attenuated strain Salmonella typhi Ty21a (1,2).

Vivotif® (Typhoid Vaccine Live Oral Ty21a) is indicated for immunization of adults and children greater than 6 years of age against disease caused by Salmonella typhi. Routine typhoid vaccination is not recommended in the United States of America. Selective immunization against typhoid fever is recommended for the following groups: 1) travelers to areas in which there is a recognized risk of exposure to S. typhi, 2) persons with intimate exposure (e.g. household contact) to a S. typhi carrier, and 3) microbiology laboratorians who work frequently with S. typhi(7). There is no evidence to support the use of typhoid vaccine to control common source outbreaks, disease following natural disasters or in persons attending rural summer camps.

Not all recipients of Vivotif® will be fully protected against typhoid fever. Vaccinated individuals should continue to take personal precautions against exposure to typhoid organisms. The vaccine will not afford protection against species of Salmonella other than Salmonella typhi or other bacteria that cause enteric disease. The vaccine is not suitable for treatment of acute infections with S. typhi.

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NEWS HIGHLIGHTS

Published Studies Related to Vivotif (Typhoid Vaccine)

Development of Vi conjugate - a new generation of typhoid vaccine. [2013]
Typhoid fever remains to be a serious disease burden worldwide with an estimated annual incidence about 20 million. The licensed vaccines showed moderate protections and have multiple deficiencies.This new generation of typhoid vaccine opens up a new era for typhoid prevention and elimination.

In a randomized, double-blinded, placebo-controlled trial, the single oral dose typhoid vaccine, M01ZH09, is safe and immunogenic at doses up to 1.7 x 10(10) colony-forming units. [2010.04.30]
M01ZH09, S. Typhi (Ty2 Delta aroC Delta ssaV) ZH9, is a single oral dose typhoid vaccine with independently attenuating deletions.

In a randomized, double-blinded, placebo-controlled trial, the single oral dose typhoid vaccine, M01ZH09, is safe and immunogenic at doses up to 1.7 x 10(10) colony-forming units. [2010]
M01ZH09, S. Typhi (Ty2 Delta aroC Delta ssaV) ZH9, is a single oral dose typhoid vaccine with independently attenuating deletions.

A cluster-randomized effectiveness trial of Vi typhoid vaccine in India. [2009.07.23]
BACKGROUND: Typhoid fever remains an important cause of illness and death in the developing world. Uncertainties about the protective effect of Vi polysaccharide vaccine in children under the age of 5 years and about the vaccine's effect under programmatic conditions have inhibited its use in developing countries... CONCLUSIONS: The Vi vaccine was effective in young children and protected unvaccinated neighbors of Vi vaccinees. The potential for combined direct and indirect protection by Vi vaccine should be considered in future deliberations about introducing this vaccine in areas where typhoid fever is endemic. (ClinicalTrials.gov number, NCT00125008.) 2009 Massachusetts Medical Society

Revaccination with locally-produced vi typhoid polysaccharide vaccine among chinese school-aged children: safety and immunogenicity findings. [2007.11]
OBJECTIVE: To evaluate the safety and immunogenicity of revaccination with locally-produced Vi polysaccharide vaccine 3 years after the first dose in Chinese children aged 9 to 14 years... CONCLUSION: We found that revaccination using the locally produced Vi polysaccharide vaccine among Chinese school-aged children was safe and increased antibody titers. Revaccination can be used to extend the duration of protection provided by Vi polysaccharide vaccine.

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Clinical Trials Related to Vivotif (Typhoid Vaccine)

Cross-reactive Immunity Elicited by Oral and Parenteral Typhoid Vaccines [Recruiting]
In a recent controlled study, the investigators explored cross-reactive immune responses against different Salmonella spp. in healthy volunteers immunized with either the oral (Vivotif® ) or parenteral (Typherix®) typhoid vaccines (ISRCTN68125331). In the present study immune responses will be studied in a group receiving both of these vaccines and in the previously immunized volunteers after booster immunization (same groups receive same vaccines 2-4 years after primary immunization).

Vaccines and Dietary Oats in the Treatment of Ulcerative Colitis [Not yet recruiting]
Ulcerative colitis is a chronic inflammatory bowel disease caused by an imbalance between natural defence mechanisms in the intestinal mucosa and microbes in the intestinal lumen. We hypothesise that an improvement or even normalisation of this balance may be achieved by the use of vaccines and dietary oats. The combined use of oral typhoid vaccine and cholera/ETEC-vaccine is supposed to stimulate mucosal defence factors, while dietary oats modifies the microbial environment inside the intestinal lumen. Or study aim is to show if such treatment brings symptom relief to patients with ulcerative colitis.

Understanding Typhoid Disease After Vaccination [Not yet recruiting]
Using an established model of human typhoid infection, whereby healthy adults are deliberately infected with typhoid-causing bacteria, the investigators will determine how effective a new oral typhoid vaccine (M01ZH09) is in preventing infection. A previously licensed oral typhoid vaccine (Ty21a) will be used to make sure the challenge model used works properly.

Studies of Immune Responses to Orally Administered Vaccines in Developing Country [Recruiting]
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.

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