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Oral Delivery of Antigens in Live Bacterial Vectors

1991; Springer Nature; Linguagem: Inglês

10.1007/978-1-4684-6000-1_18

2214-8019

Robert N. Brey, Garvin S. Bixler, James P. Fulginiti, Deborah A. Dilts, Marta Sabara,

Hepatitis Viruses Studies and Epidemiology

Most available vaccines for enteric diseases are cinactivated whole cell preparations which provide incomplete cprotection against infection and have undesirable side effects. cAs alternative vaccines for enteric infection, several live oral cvaccines have been recently developed. These vaccines are cderived from virulent pathogens by introduction of stable cattenuating mutations in metabolic pathway genes. Ideally, cthese mutations are non-reverting and genetically well defined. cThe Salmonella typhi live oral vaccine Ty21a has been tested in cseveral field trials, first in Egypt and more recently in four cseparate trials in Chilean schoolchildren (Ferreccio et al, 1989; Levine et al 1987a; Wahdan et al, 1982). The results of cthose trials indicate that Ty21a is safe, well tolerated, and cprovides 66% protection in a typhoid fever endemic area. cProtection against typhoid fever was at least that achieved with cparenterally administered whole cell vaccine preparations and cwas retained for at least three years.