The World Health Organization (WHO) is establishing a new Strategic Advisory Group of Experts on Immunization (SAGE) Working Group on Oral Cholera Vaccines.
SAGE Working Groups are members provide evidence-based information and options for recommendations to the WHO. These Working Groups are normally established on a time limited basis to help address specific when the issue cannot be addressed by existing standing WHO advisory committees.
Cholera Outbreaks & Prevention
Cholera has produced 7 pandemics and remains a significant and neglected public health threat, which disproportionately affects the poor and imposes significant economic costs. Cholera outbreaks continue to spread across many countries with dramatic consequences, overwhelming stretched health systems and diverting resources from other programs. Endemic situations are not controlled in a number of rural and urban settings in Africa, Asia and Haiti.
In 2011, the World Health Assembly recommended a revitalized Global Task Force on Cholera Control (GTFCC) and called for strengthening of WHO’s work in this area, including improved collaboration and coordination among relevant stakeholders.
Cholera is predictable, preventable and can ultimately be eliminated where access to clean water and sanitation facilities, and satisfactory hygienic conditions are ensured and sustained for the whole population. Although the mainstay for cholera control remains access to safe water and sanitation, there is more and more evidence that high coverage with oral cholera vaccines (OCV) results in significant reduction of cholera transmission in various settings.
Oral Cholera Vaccines
Two vaccines are currently pre-qualified by WHO: Dukoral and Shanchol. Both are oral killed whole-cell vaccines that provide sustained protection of >50% for at least two years, induce an immune response relatively quickly (7-10 days after the 2nd dose) and have a good safety profile. Shanchol has demonstrated longer term protection – 65% over five years – as compared to Dukoral.
On the other hand, Dukoral has been shown to provide better short-term protection against cholera, particularly among children 2-5 years old and also confers significant short-term protection against ETEC (≈50% for three months). Both vaccines have a two-dose regimen between one and six weeks apart.
Since 2010, the WHO recommendation is to use these vaccines in conjunction with other prevention and control strategies in areas where the disease is endemic and in areas at risk for outbreaks. Vaccination should not disrupt the provision of other high-priority health interventions to control or prevent cholera outbreaks.
In 2013, WHO formally established a stockpile of 2 million doses for outbreak control and emergencies and the GAVI board approved a contribution to the global cholera stockpile for use in epidemic and endemic settings, with an investment covering the period 2014-2018.
As of September 2015, the stockpile has supported 23 mass campaigns implemented in various outbreak and hotspot settings.
Working Group Goals
The SAGE Working Group on Oral Cholera Vaccines has the following stated goals:
- Analyze the results of the most recent OCV research activities, including safety and effectiveness
- Assess community acceptance issues
- Perform cost analysis of the impact on cholera transmission in endemic and epidemic settings
- Review evidence and propose recommendations for use of OCV in pregnant and lactating women
- Review evidence and propose recommendations for use of OCV in travelers
- Review evidence and propose updated recommendations for vaccination strategies (Controlled Temperature Chain, single dose, self-administration, administration with other vaccines, ring vaccination)
- Examine the 2010 WHO recommendations on OCV use and propose potential adjustments
The working group is expected to be set up and start functioning by December 2015, and is expected to accomplish its task and tentatively present its conclusions in April 2017.