Vaccine-Preventable Diseases Surveillance Standards
DISEASE AND VACCINE CHARACTERISTICS
Cholera is a diarrhoeal disease caused by toxigenic serogroups of the bacterium Vibrio cholerae, which can cause rapid dehydration and death. Cholera is closely
associated with poverty, poor sanitation and lack of clean drinking water. As such, the cholera burden is concentrated in Africa and southern Asia, accounting for about 99% of worldwide cases. Cholera can be endemic and cause epidemics. Cholera bacteria are spread by direct faecal-oral contamination or ingestion of contaminated water or food. The incubation period is less than 24 hours to 5 days. Only up to 25% of infected persons become symptomatic; of these, 10–20%
experience severe disease. Severe disease manifests as acute, profuse watery diarrhoea (“rice water stools”), usually with vomiting. This leads to rapid dehydration, which can result in hypotensive shock, renal failure and death within hours of onset.
The cholera case fatality rate should be below 1% where access to care with proper rehydration services (oral and/or intravenous) is available, but it may reach 5% in the most vulnerable settings. Cholera affects all age groups, although half of the cholera deaths are inchildren < 5 years of age. Current estimates of cholera
cases range from 1.4 to 4 million, and estimated cholera deaths range from 21,000 to 143,000 (1). However, global burden of cholera is underestimated due to
contributing factors such as low reporting, limited epidemiological surveillance and lack of laboratory capacity.
Two types of killed whole-cell oral cholera vaccines are available: a monovalent (O1) vaccine with a recombinant B subunit of the cholera toxin, and a bivalent (O1 and O139) without the B subunit. The vaccines are given as two- or three-dose regimens. Neither vaccine is recommended for infants. Cholera vaccines are recommended in endemic settings, during cholera outbreaks and in humanitarian crises with risk of cholera. WHO has maintained a stockpile of cholera vaccine since 2013 to be used in these situations, upon request of the country. Cholera vaccines should always be used in conjunction with other cholera prevention and control strategies