Salmonella Research Today is a free monthly online journal that collates and summarizes the latest research about Salmonella, including details on salmonella typhimurium, food poisoning, infection, treatment.

Ty21a live oral typhoid vaccine and prevention of paratyphoid fever caused by Salmonella enterica Serovar Paratyphi B.

Levine MM, Ferreccio C, Black RE, Lagos R, San Martin O, Blackwelder WC

Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD 21201, USA. mlevine@medicine.umaryland.edu

In randomized, controlled field trials in Area Norte and Area Occidente of Santiago, Chile, 2 (Norte) or 3 (Occidente) doses of live oral typhoid vaccine Ty21a in enteric-coated capsules conferred protection against confirmed Salmonella enterica serovar Typhi disease (53% efficacy in Norte; 67% efficacy in Occidente) during 3 years of follow-up. There was also a trend in each trial showing protection against S. enterica serovar Paratyphi B disease (56% efficacy in Norte; 42% efficacy in Occidente). To enhance statistical power, an analysis was performed using pooled data from the 2 trials; this pooling of data was justified by the following facts: epidemiologic surveillance and microbiological methods were identical, the trials overlapped during 22 of the 36 months of follow-up in each trial, the estimates of efficacy against paratyphoid B fever in the 2 trials were roughly similar, and the ratio of follow-up of vaccine recipients to control subjects in both trials was ~1 : 1. In the pooled analysis, Ty21a conferred significant protection against paratyphoid B fever (efficacy, 49%; 95% confidence interval, 8%-73%; P=.019).

Published 21 June 2007 in Clin Infect Dis, 45: S24-8.
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