Effectiveness of an oral cholera vaccine campaign to prevent clinically-significant cholera in Odisha State, India.

BACKGROUND: A clinical trial conducted in India suggests that the oral cholera vaccine, Shanchol, provides 65% protection over five years against clinically-significant cholera. Although the vaccine is efficacious when tested in an experimental setting, policymakers are more likely to use this vaccine after receiving evidence demonstrating protection when delivered to communities using local health department staff, cold chain equipment, and logistics. METHODS: We used a test-negative, case-control design to evaluate the effectiveness of a vaccination campaign using Shanchol and validated the results using a cohort approach that addressed disparities in healthcare seeking behavior. The campaign was conducted by the local health department using existing resources in a cholera-endemic area of Puri District, Odisha State, India. All non-pregnant residents one year of age and older were offered vaccine. Over the next two years, residents seeking care for diarrhea at one of five health facilities were asked to enroll following informed consent. Cases were patients seeking treatment for laboratory-confirmed V. cholera-associated diarrhea. Controls were patients seeking treatment for V. cholerae negative diarrhea. RESULTS: Of 51,488 eligible residents, 31,552 individuals received one dose and 23,751 residents received two vaccine doses. We identified 44 V. cholerae O1-associated cases and 366 non V. cholerae diarrhea controls. The adjusted protective effectiveness for persons receiving two doses was 69.0% (95% CI: 14.5% to 88.8%), which is similar to the adjusted estimates obtained from the cohort approach. A statistical trend test suggested a single dose provided a modicum of protection (33%, test for trend, p=0.0091). CONCLUSION: This vaccine was found to be as efficacious as the results reported from a clinical trial when administered to a rural population using local health personnel and resources. This study provides evidence that this vaccine should be widely deployed by public health departments in cholera endemic areas.

A hepatitis E outbreak caused by a temporary interruption in a municipal water treatment system, Baripada, Orissa, India, 2004.

In January 2004, we investigated a cluster of acute hepatitis in Baripada, Orissa, India. Between January and March 2004, 538 cases (definition: fever with loss of appetite and jaundice) were reported (attack rate: 263 per 100 000, 5 deaths, case fatality rate: 0.93%). Forty-seven of 48 sera were positive for IgM antibodies to hepatitis E virus. Cases peaked in February 2004 and decreased rapidly, suggesting a common source outbreak. Five neighbourhoods supplied by a common water supply were most affected. Ninety-one percent of the 538 cases and 30% of 538 unaffected controls reported drinking water from one source (odds ratio 31, 95% CI 27-48). The neighbourhood's water was pumped directly from a river and had not been treated during a 10-day period in early January (1 month before the peak of the outbreak) because of a strike at the treatment plant. This large hepatitis E outbreak was associated with drinking untreated raw river water. Measures must be in place to check the quality of municipal water and to ensure essential services in case of strikes.