ABSTRACT
Introduction: Cholera remains a public health threat. The development of safe, effective, easy-to-administer, heat-stable, and cheap killed whole cell oral cholera vaccines (OCVs) has provided an additional tool to counter cholera. In this meta-opinion, we review the challenges of delivering OCVs through the existing public health infrastructure in vulnerable areas.
Areas covered: We provide an overview of the available vaccines against cholera, the existing evidence about the effectiveness of a two-dose as well as a single-dose OCV strategy. We also highlight the experience from the public health campaigns for OCV deployment.
Expert opinion: Several public health experiences have shown the feasibility of incorporating OCVs into the public health response against cholera. Combined with a comprehensive water, sanitation, and hygiene (WaSH) improvement plan, OCVs need to be deployed in identified vulnerable areas, targeting the highest risk groups first. Vaccination programs should not be deployed in lieu of investments in WaSH services, but as a complimentary service in a comprehensive, cholera control intervention package. It has been a challenge to have high two-dose coverage across all eligible recipients, necessitating the adoption of innovative strategies to boost coverage. Longer intervals between doses may help to overcome resource and logistical limitations enabling higher coverage.
Article highlights
Despite significant improvements in access to safe water, adequate sanitation, and hygiene facilities (WaSH), cholera remains a major public health problem, especially in areas experiencing sociopolitical unrest, with consequent compromises to the public health infrastructure.
The development of cheap, heat-stable, effective, and easy-to-administer oral cholera vaccines (OCVs), which have been prequalified by WHO, and incorporated into the vaccine stockpile maintained by GAVI, has opened up newer avenues to counter the threat of cholera globally.
Since the development of the OCV stockpile, global demand for OCV use has been on the rise; over 7 million doses have been delivered, on demand, in endemic settings (Haiti), in response to outbreaks (Malawi, Zambia), or in settings of humanitarian crises (Niger, South Sudan, Bangladesh for Forcibly Displaced Myanmar Nationals).
In endemic settings, cholera remains largely limited to hotspots – foci of intense and persistent disease transmission; the biggest challenge in using OCVs in these settings remains delivering two doses of OCV to a high proportion of the target population.
Factors which limit the extensive deployment of OCVs include regulatory hurdles; supply side issues; covering adults who are usually not under the ambit of vaccination programs; hesitancy, suspicion, and cultural barriers limiting vaccine uptake in susceptible populations; and poor uptake of second dose of OCVs in vaccine recipients.
OCVs should be deployed as part of a comprehensive cholera control plan, in line with the WHO’s Global Task Force on Cholera Control’s (GTFCC) roadmap to end cholera by 2030; synergistic use of OCVs, WaSH improvement and community mobilization are key to reach the target of cholera control on a global scale.
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Declaration of Interests
The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.
Reviewer disclosures
Peer reviewers on this manuscript have no relevant financial relationships or otherwise to disclose.