Eliminating Cholera Transmission in Haiti

December 7, 2016

Louise C. Ivers, M.D., M.P.H.

On October 13th and 14th, 2016, the Minister of Health and Population of Haiti, Dr. Daphnee Benoit,  convened an expert panel to consult on the control of cholera in Haiti with specific reference to the use of vaccines in the aftermath of Hurricane Mathew; the consultation resulted in the following consensus.

When Hurricane Matthew struck on October 4, 2016, it left 1.4 million people in southern Haiti in need of urgent humanitarian assistance — destroying homes and health care facilities, flooding water sources with runoff, ruining crops, killing livestock, and displacing hundreds of thousands of people. Looming as the next act in the disaster is a resurgence in endemic cholera.

Cholera was not recorded  in Haiti until it was introduced in 2010. The introduction of Vibrio cholerae into a population that had never been exposed to cholera and that had extremely limited access to safe water and sanitation had a predictable effect: an explosive cholera epidemic that has killed at least 10,000 people and caused nearly 800,000 reported cases throughout the country1. Three weeks after Hurricane Matthew, the number of cholera cases has grown, and we are concerned about the impact on human life.

Now in its seventh year, the epidemic has taken an immeasurable toll on individuals, communities, and the health system in Haiti, and the resources for controlling it have been too limited. In 2015, Haiti reported more cases of cholera per population than any other country. In 2016, there were 29,000 cases of cholera in the first 9 months of the year — already a disaster before the hurricane. And as is so often the case, the poor have suffered the most. New approaches are needed to address the ongoing problem and mitigate suffering from cholera in Haiti. The hurricane’s aftermath adds urgency to this problem.

The response to Hurricane Matthew must first and foremost address the victims’ need for humanitarian relief, through provision of food, shelter, and clean water to those who lack these life-saving essentials. Rallying emergency clean-water activities to combat the known risk of cholera in the immediate phase is an important strategy. We should assume, at least initially, that there has been further contamination of fresh water sources in Haiti’s southern peninsula. Ensuring that people have access to and use effectively chlorinated water, with safe water storage at home (or in shelters), is a critical life-saving objective.

There is a simultaneous need to ensure that cholera treatment centers and oral rehydration posts are functional. After the hurricane, many of these facilities will have to be rebuilt; resupplied with rehydration fluids, antibiotics, and zinc for children; and supported with staff for effective case finding in the community and rapid treatment of the sick. These strategies have not changed since the beginning of the cholera epidemic in 2010, although in recent years resources to implement them have dwindled.

When the cholera epidemic began in Haiti, and for some years afterward, there was a lack of consensus on the role that oral cholera vaccine (OCV) could play in the response. One clear issue, however, was that the supply of vaccine was very limited, and there was limited experience in using OCVs in response to outbreaks. Furthermore, the fact that the vaccine had not yet met prequalification requirements of the World Health Organization (WHO) meant that UNICEF and other United Nations agencies could not purchase it.

Since that time, a number of developments have enhanced our ability to control the epidemic in Haiti. Two safe, effective OCVs are now available at affordable cost ($1.70 to $1.85 per dose), are prequalified by the WHO, and are available in increasing quantities. The products are essentially the same vaccine, made by different manufacturers. Shanchol (Sanofi-Pasteur, India) was prequalified in 2011. In 2013, a 2-million-dose OCV stockpile was established as a public good to manage the vaccine. Euvichol (Eubiologics, South Korea) was prequalified by the WHO in 2015, and the manufacturer recently announced that it could produce 25 million single-dose vials per year that remain stable at 37°C for 30 days, avoiding wastage and enabling delivery to the most remote areas without a requirement for a stringent cold chain.  Other OCVs are available (VaxChora, PaxVax, United States; Dukoral, Crucell, Sweden), but are not considered practical for major public health use in resource-poor settings at this time.

Finally, a series of studies with OCVs in Haiti have demonstrated the efficacy of the Shanchol vaccine in both urban and rural settings, the feasibility of achieving high coverage rates, and the low cost of delivering this vaccine to the population. In one of the poorest urban slums of Haiti, not a single case of culture-confirmed cholera occurred between September 2013 and August 2016 in persons who had received  a combined intervention ensuring household chlorination and cholera vaccination2-4. This research complements other recent OCV studies from Guinea and South Sudan.

This information fundamentally changes the way health authorities should now consider the use of OCV in controlling cholera. Mass vaccination in Haiti would save lives, and modeling suggests that such an intervention, coupled with targeted, effective water, sanitation, and hygiene interventions, could substantially control, if not eliminate, the disease within a few years of the program’s introduction and at an affordable cost. This medium-term plan will have to be undertaken in concert with a long-term effort to realize the human right of access to clean water, a goal that will require a substantial budget and years, if not decades, to accomplish. Control of cholera was a problem in Haiti for the 6 years before Hurricane Matthew — not only because there were insufficient resources, but also owing to the enormity of the challenge of redressing the population’s severely constrained access to clean water and sanitation.

One million doses of OCV were requested by the Haitian Ministry of Public Health and Population and authorized as part of the emergency response to Hurricane Mathew.5 Two shipments of 500,000 doses arrived in Haiti on October 24 and 25, 2016, and the vaccines have been deployed by the Ministry of Health and its partners for urgent use. We of the Special Consulting Group to the Minister of Health and Population of Haiti commend the mass-vaccination approach in the hurricane-affected areas of the south of Haiti as one part of a comprehensive emergency response. In light of recent data on vaccine efficacy, feasibility of vaccinating in outbreak settings,, and the increased availability of safe, effective, and low-cost vaccines, we urge that the humanitarian delivery of OCVs after the hurricane also be immediately provided to the affected communities, along with  intense and reinvigorated support for the Government’s National Plan for the Elimination of Cholera in Haiti, including a nationwide two-dose oral cholera vaccination campaign.

Over the past six decades, several public health programs in Haiti (e.g. HIV care and treatment; control of neglected tropical diseases) have provided models for the world. The increased availability of OCVs and their rollout in a national program could provide an opportunity for the government of Haiti and the international community to demonstrate another successful strategy: comprehensive national OCV coverage combined with targeted water, sanitation, and hygiene interventions could eliminate the transmission of cholera in Haiti over the next 3 to 5 years at an affordable cost (some estimates suggest approximately $66 million). This goal is surely one to aspire to, given the human cost of maintaining the status quo.

Eliminating cholera transmission in Haiti with a combined, integrated approach at the population level would be a major achievement for the government and people of Haiti. It  would also have broad implications for the control of cholera in other affected populations around the world. The time for ambitious action on cholera control and elimination in Haiti is now.

 

Disclosure forms provided by the author are available at NEJM.org.

 

From the Division of Global Health Equity, Brigham and Women’s Hospital, Boston; and the Special Consulting Group to the Minister of Health and Population of Haiti. The other members of the Special Consulting Group were Dr. Daphnee Delsoin Benoit, the Honorable Minister of Health and Population, Haiti; Dr. Dennis Chao, Institute for Disease Modeling; Dr. Donald Francois, Ministry of Health and Population, Haiti; Dr. Jeannot Francois, Director of Expanded Program on Immunization, Ministry of Health and Population, Haiti; Dr. Roger Glass, Fogarty International Center, NIH; Dr. Robert Hall, National Institute of Allergy and Infectious Disease, NIH; Dr. Jerome H. Kim, International Vaccine Institute; Dr. Bernard Liautaud, Ministry of Health, Haiti; Prof. Ira Longini, University of Florida; Ms. Helen Matzger, Bill and Melinda Gates Foundation; Dr. Vittal Mogasale, International Vaccine Institute; Prof. Glenn Morris, University of Florida; Prof. Jean William Pape, Weill Cornell Medical College; and Prof. David Sack, Johns Hopkins University and Dr. Jordan Tappero, Centers for Disease Control and Prevention.

 

 

 

References

  1. Barzilay EJ, Schaad N, Magloire R, et al. Cholera surveillance during the Haiti epidemic–the first 2 years. The New England Journal of Medicine 2013;368:599-609.
  2. Severe K, Rouzier V, Anglade SB, et al. Effectiveness of Oral Cholera Vaccine in Haiti: 37-Month Follow-Up. Am J Trop Med Hyg 2016;94:1136-42.
  3. Ivers LC, Hilaire IJ, Teng JE, et al. Effectiveness of reactive oral cholera vaccination in rural Haiti: a case-control study and bias-indicator analysis. Lancet Glob Health 2015;3:e162-8.
  4. Tohme RA, Francois J, Wannemuehler K, et al. Oral Cholera Vaccine Coverage, Barriers to Vaccination, and Adverse Events following Vaccination, Haiti, 2013. Emerg Infect Dis 2015;21:984-91.
  5. Gavi The Vaccine Alliance. Gavi provides support for emergency cholera vaccine campaign in Haiti. http://www.gavi.org/library/news/statements/2016/gavi-provides-support-for-emergency-cholera-vaccine-campaign-in-haiti/ Accessed Nov 16, 2016.