As cholera continues to surge — and as vaccines remain in short supply — experts are warning about the global risk.

Cholera is a bacterial disease typically spread by food and water, leading to severe diarrhea and dehydration. It has been on the rise around the world since 2021.

Each year, there are some 1.3 to 4 million cases of cholera worldwide, according to the World Health Organization (WHO). Approximately 21,000 to 143,000 deaths occur as a result.

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Around 473,000 cases were reported to WHO in 2022, which was twice as many cases as the prior year.

Reported cases for 2023 are expected to exceed 700,000.

“It is concerning to see an increase in the number of cholera cases worldwide, with the majority of the cases in Asia, Africa and Latin America,” Dr. Renuga Vivekanandan, M.D., assistant dean and professor at the Creighton University School of Medicine in Omaha, Nebraska, told Fox News Digital.

The countries most affected include the Democratic Republic of the Congo, Ethiopia, Haiti, Somalia, Sudan, Syria, Zambia and Zimbabwe, according to UNICEF. 

The disease can spread quickly in locations where there is insufficient treatment of drinking water and sewage. 

Although cholera cases were prevalent in the U.S. in the 1800s, water treatment systems have largely eliminated the disease, per the CDC.

In rare cases, people in the U.S. have contracted the disease from consuming raw or undercooked shellfish from the Gulf of Mexico, the agency stated on its website.

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“In the U.S., the cases have remained very small and are usually from travel exposure,” Vivekanandan noted.

Why the spike in global cases?

Cholera is typically spread when someone drinks water or eats food that is contaminated with the bacterium Vibrio cholerae, according to the CDC.

The disease can spread quickly in locations where there is insufficient treatment of drinking water and sewage, the agency warned.

It is not typically transmitted from person to person. 

UNICEF noted in a statement that the rise in cholera is driven by “persistent gaps in access to safe water and sanitation.”

“In the U.S., the cases have remained very small and are usually from travel exposure.”

“I think the cases might be increasing due to climate change, displacements of homes due to disasters, and not having good sanitary conditions, such as poor water sources,” Vivekanandan told Fox News Digital.

Symptoms of cholera

Around 10% of the people who are infected with cholera will develop severe symptoms, including watery diarrhea, vomiting and leg cramps, according to the U.S. Centers for Disease Control and Prevention (CDC).

Advanced symptoms include shock and dehydration. 

Without treatment, the disease can be fatal.

“Dehydration is the biggest concern with cholera, and rehydration is the most important component of treatment,” said Vivekanandan.

“Most patients with cholera will have mild diarrhea, but 10% will have severe diarrhea and will need rehydration and treatment with antibiotics.”

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Some groups are more susceptible to the disease, according to the CDC.

“Individuals with achlorhydria (the absence of hydrochloric acid in digestive stomach juices), blood type O, chronic medical conditions, and those without ready access to rehydration therapy and medical services are more likely to have severe disease from cholera and suffer poor outcomes,” the agency noted.

Treatment and prevention

The most effective treatment for cholera is “immediate replacement of the fluid and salts lost through diarrhea,” the CDC stated.

This is achieved by giving patients a mixture of sugar and salts mixed with 1 liter of water. 

In some severe cases, the patient may require intravenous (IV) fluids.

Some patients also receive antibiotics to make symptoms less severe.

“Persons who develop severe diarrhea and vomiting in countries where cholera occurs should seek medical attention promptly,” per the CDC.

There is a single-dose vaccine for cholera, called Vaxchora (lyophilized CVD 103-HgR).

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Those who are between the ages of 2 and 64 and who are traveling to “an area of active cholera transmission” are eligible to receive it.

There are three other cholera vaccines, but they are not available in the U.S.

What to know about vaccine shortage

There is a “severe gap” in the number of available vaccine doses compared to the level of current need, said UNICEF on its website.

“Between 2021 and 2023, more doses were requested for outbreak response than the entire previous decade,” UNICEF noted.

While cholera vaccines used to be administered in two doses, the International Coordinating Group (ICG) changed the recommendation to a single dose in Oct. 2022 due to the ongoing shortage.

Vivekanandan called the vaccine shortage “very concerning.”

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“This is a serious infection, and we must invest financial and other resources to reduce the worldwide burden,” he told Fox News Digital.

“International resources need to be committed, and partnerships with pharmaceutical companies need to happen to help produce more vaccines.”

“This is a serious infection, and we must invest financial and other resources to reduce the worldwide burden.”

Vivekanandan also urged people who are traveling from the U.S. to other countries to review the CDC’s travel guidance and get any required vaccines.

“I would also recommend that people follow good travel medicine guidance, such as drinking bottled water, eating well-cooked food and making sure to have good hand hygiene,” he added.

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“As the WHO has stated, we need to have multi-pronged approaches, with a combination of surveillance, water, sanitation and hygiene, social mobilization, treatment, and oral cholera vaccines available for communities at high risk.”

On the U.S. Food and Drug Administration (FDA) website, Vaxchora is listed as a “resolved shortage.”

The FDA noted that Emergent Travel Health, manufacturer of the vaccine, announced in May 2021 the temporary discontinuation and distribution of Vaxchora, “due to a significant reduction of international travel caused by the COVID-19 pandemic.”

The shortage is listed as having been resolved in May 2023.

Fox News Digital reached out to WHO, the FDA and Emergent requesting comment.

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