Two-year study of the protective efficacy of the oral whole cell plus recombinant B subunit cholera vaccine in Peru.

The protective efficacy of an oral inactivated whole cell Vibrio cholerae plus recombinant B subunit cholera vaccine was determined against El Tor cholera among Peruvian children and adults (2-65 years old) in a randomized, double-blind manner. Study subjects received 2 doses of vaccine or placebo 2 weeks apart, followed by a booster dose 10 months later. Surveillance for cholera was performed actively, with 2 visits per week to each household, and passively, at a local hospital. Stool samples were collected during diarrhea episodes and were cultured for V. cholerae. A total of 17,799 persons received 2 doses of vaccine or placebo, and 14,997 of these persons received the booster dose. After 2 doses (first surveillance period), V. cholerae biotype O1 was isolated from 17 vaccinees and 16 placebo recipients, demonstrating vaccine efficacy (VE) of -4%. After 3 doses (second surveillance period), V. cholerae O1 was isolated from 13 vaccinees and 32 placebo recipients, demonstrating VE of 61% (95% confidence interval ¿CI, 28%-79%). In the second surveillance period, the VE for illness requiring hospitalization was 82% (95% CI, 27%-96%). VE was also higher for persons >15 years old (VE, 72%; 95% CI, 28%-89%).

Water source as risk factor for Helicobacter pylori infection in Peruvian children. Gastrointestinal Physiology Working Group.

Helicobacter pylori infection is widespread among Peruvian adults by the age of 30, but the age at which children become infected, the prevalence of disease, and the role of socioeconomic status in the epidemiology of infection are not known. We used the 13C-urea breath test to study the prevalence of infection in 407 Peruvian children from Lima, aged 2 months to 12 years, from families of low and high socioeconomic status. Peruvian children acquire H pylori early in life and the number of infected individuals increases rapidly with age; overall prevalence was 48%. H pylori infection was independent of sex, but was highly correlated with socioeconomic status; prevalence of infection was higher among children from low-income families than among those from high-income families (56% vs 32%, p = 0.001). Children whose homes had external water sources were three times more likely to be infected than were those whose homes had internal water sources. Among families with internal water sources, there was no difference in H pylori infection associated with income. Children from high-income families whose homes were supplied with municipal water were 12 times more likely to be infected than were those from high-income families whose water supply came from community wells. The findings show that the prevalence of H pylori infection is high among young Peruvian children and that the municipal water supply seems to be an important source of infection among Lima children from families of both low and high socioeconomic status.