Cholera has killed roughly 3,800 people in Haiti and sickened another 189,000, and it will continue to circulate in the population for the foreseeable future. The good news is that the number of new cases per week has dropped from 12,000, which it reached in November, to about 4,700, and the mortality rate has also decreased. Intensive treatment and prevention efforts (including provision of clean water and educational campaigns) have saved thousands of lives, and will have to continue even as the attention of the international community wanes.

David Cyranoski of Nature News points out that success has been uneven, though: rural areas still have high infection and mortality rates, because many rural residents live far from health facilities and their areas have received less assistance with water quality, sanitation, and hygiene.

Last month, NPR’s Richard Knox reported that public health officials are starting to give more consideration to the idea of a vaccination campaign. While many officials were reluctant to draw resources away from treatment and sanitation efforts during the outbreak’s early stages, they’re now looking at a longer-term picture. They also know now that the cholera strain circulating in Haiti is more lethal than others, and that more vaccine may be available than previously thought. Even so, there are several factors that will make a vaccination campaign challenging.

The World Health Organization has “pre-qualified” only one cholera vaccine, Dukoral, and there are only enough doses available right now to vaccinate 50,000 people, Knox explains. (Adults require two doses and children under six need three, so the number of available doses is higher than the number of people who’ll be vaccinated.) Another vaccine, Shanchol, is cheaper and easier to administer, but hasn’t yet gotten the WHO pre-qualification that would allow UN agencies to buy it.

In an article last week, Cyranoski reported that there are one million doses of Shanchol – which is approved for use in India – and that vaccine might get WHO approval by March. An expert committee convened by WHO recommends launching a pilot project using the currently available doses of Dukoral and creating a larger stockpile for the future. But a small pilot might not go over well in Haiti, Cyranoski explains:

[U]sing the world’s entire stockpile of doses would still leave most Haitians without vaccine — a controversial prospect for the beleaguered government. Jean Ronald Cadet, the [Haitian Ministry of Health's] vaccination programme manager, says the country is “90%” ready to go ahead with a campaign — but not on the small scale the WHO-convened expert group envisages.

Asked about the small pilot project proposed by the group, Cadet says “No way,” shaking his head. He insists that Haiti would only consider starting to vaccinate with more than 1 million doses, with a goal of eventually reaching 6 million people. “It would depend on the pressure that the international community can put on manufacturers.” Who would pay for the doses? “The international community,” he says. “They brought us cholera, they have to take responsibility for taking care of it.”

It’s a daunting challenge, but a Lancet piece by authors from Harvard Medical School and Partners in Health/Zanmi Lasante points out that ambitious health efforts have succeeded in Haiti before:

This year, Haiti might have marked World AIDS Day on Dec 1 with some degree of celebration: as chroniclers of the pandemic have noted, Haiti helped lead the way towards an integrated AIDS prevention and care model that was adopted in many resource-poor settings when funding from new mechanisms became available. The size of Haiti’s AIDS epidemic has been halved over the past 15 years; AIDS-related stigma was reduced when treatment became available; and, in some settings, a significant fraction of HIV funding was steered into strengthening regional and local health systems.

After giving that context, Louise C. Ivers, Paul Farmer, Charles Patrick Almazor, and Fernet Léandre call for complementary interventions in cholera prevention and treatment in Haiti: better treatment (including more health workers in rural areas and antibiotics as well as oral rehydration therapy), vaccination, improvements in water security and sanitation, a strengthened health system, and raising the bar on goals. “No epidemic of cholera is ever local for long,” they remind us, “and this one is particularly fast-growing.” A vigorous campaign to slow cholera and improve health in Haiti could prevent similar devastation elsewhere in the hemisphere.