Global Campaign To Reduce Cholera Deaths Is Bogged Down. Why?

“The ancient disease of cholera is making a comeback in 2024—but the world’s supply of vaccines can’t keep up.”

Gabriel Emanuel, PhD, reporter, GBH News

“Be careful! Travel expands the mind and loosens the bowels.”

Abraham Verghese, MD, Professor of Theory and Practice of Medicine, Stanford University Medical School

In October 2017, the World Health Organization (WHO) launched “ROADMAP 2030,” a global strategy to reduce cholera deaths by 90% and to stop its transmission by 2030. Unfortunately, the WHO’s campaign has bogged down. As of February 2024, 11 countries were reporting active cholera outbreaks, and the WHO had classified six countries in “acute crisis” for cholera. In this week’s Germ Gems post, I provide my assessment of what makes achieving the WHO’s goal such a challenge.

What is cholera? Cholera is a life-threatening diarrheal disease caused by the toxin-producing gram-negative bacterium Vibrio cholerae.  While V. cholerae is transmitted primarily by drinking water contaminated with human feces, consuming contaminated raw or undercooked seafood, especially shellfish, is another route of infection.

Most people who get infected have either mild symptoms or no symptoms. But about 10% of infected people develop severe watery diarrhea—as much as 1 liter (about a quart) an hour—that can lead to profound, even fatal dehydration if untreated. The watery diarrhea (aka “rice water stools” because they are milky white) is the hallmark of the disease.

Cholera pandemics.  As devasting pandemics go, cholera is right up there with smallpox and bubonic plague. Since the 19th century, there have been seven cholera pandemics. While the last major pandemic of plague ended in the early 20thcentury, and a heroic vaccination campaign eradicated smallpox in 1980, cholera is still going strong.

We are now in the midst of the seventh cholera pandemic—a pandemic that began in 1961. And cholera seems assured of maintaining its heinous status due to ongoing human conflicts and three serious public health failures: (1) the lack of access to safe drinking water in the developing world; (2) the depleted stockpile of cholera vaccine; and (3) the inability to put the brakes on climate change.

In 2010, the United Nations declared safe water and sanitation a basic human right.  Yet, many developing countries still don’t have clean water. Every year, an estimated 1.3 to 4 million people around the world get cholera, and it kills between 21,000 to 143,000 people. What all these people have in common is that they live in impoverished countries where they lack access to safe drinking water.

Cholera vaccines.  I first discussed cholera in my December 1, 2019 Germ Gems post, “Cholera: When Water Turns Deadly.” At that time Haiti, which had seen almost a million cases and 10,000 deaths due to a cholera outbreak that began in 2010, was celebrating a milestone—“one-year free of cholera.”   Haiti’s initial success in controlling cholera wasn’t due to an engineering or technological breakthrough for dispensing safe water. Instead, it was due in large part to a countrywide effort of providing vaccinations against V. cholerae.  (Unfortunately, by the end of 2023, Haiti was experiencing another cholera outbreak.)

After witnessing the successful vaccination campaign that helped contain the cholera outbreak in Haiti, in 2013 the WHO teamed up with other public health groups to create a stockpile of oral cholera vaccine (OCV) “to help control cholera epidemics by ensuring a timely and targeted deployment of vaccines during outbreaks.” The global partnership involved various aspects of building and distributing vaccine from the stockpile. Partners included non-profit organizations, such as The Vaccine Alliance (Gavi), Bill and Melinda Gates Foundation, Medecins Sans Frontieres (Doctors Without Borders), UNICEF, and Federation of Red Cross, as well as a number of governments, including the U.S., EU, India, South Africa, and South Korea. For years, the OCV stockpile grew, from roughly 2 million doses in 2013 to about 40 million doses a decade later.

Then the number of cholera outbreaks began to rise. By 2024, the demand for cholera vaccines had outstripped supply and emptied the global stockpile. Two recent articles tell this tragic story and relate the strategies under development to deal with the crisis. (See  “How did the world run so low on cholera vaccine? As outbreaks grow, stockpile runs dry” by GBH News reporter Gabriel Emanuel, March 8, 2024; and “Global Stockpile of Cholera Vaccine Is Gone as Outbreaks Spread” by New York Times journalist Stephanie Nolan).

Links between cholera and climate change. Human conflicts, a deficiency of safe drinking water, and depletion of the OCV stockpile are not the only culprits thwarting the WHO’s effort to end transmission of V. cholerae globally by 2030. Climate change also plays a role.

Climate change can create conditions that are ideal for V. cholerae to thrive. For example, extreme events such as flooding and droughts can reduce the access to clean water. Moreover, as a consequence of increased production of greenhouse gases (carbon dioxide, methane, nitrous oxide, and fluorinated gases) and their release into Earth’s atmosphere, the oceans of our planet are warming. And while we humans may not be able to stand the heat, V. cholerae can; it flourishes when water temperatures rise thereby increasing the concentration of the bacterium in ocean water. On top of that, siphoning of saltwater by shellfish like oysters speeds up and during this process shellfish pick up more V. cholerae bacilli which await consumption by lovers of raw oysters and other raw seafood.  

What’s on the horizon? The challenge to end cholera transmission by 2030 seems daunting. But it is good to remember the achievement of the partnerships that initially built the OCV stockpile. Can they do it again?

According to a recent STAT article, the Korean vaccine manufacturer EuBiologics Co. is producing a new vaccine called Euvichol-S, a simplified version of two existing oral vaccines. (See, May 9, 2024 STAT article by Annalisa Merelli, “A new cholera vaccine will increase supply, but will it be enough to manage global outbreaks?”) The company is online to produce 50 million cholera vaccine doses in 2024.

With availability of such new vaccines plus innovative technologies under development to remove contaminants from drinking water, perhaps the cholera pandemic like the defeated smallpox and sidelined plague, can be substantially slowed, if not conquered. Whether this can happen by 2030 or not, remains to be seen. But let’s all hope so.