1 of 5 | Vaccine expert Dr. Peter Hotez calls it "shortsighted" of the U.S. government not to keep a national cholera vaccine stockpile. Photo courtesy of Dr. Peter Hotez
WASHINGTON, Oct. 13 (UPI) -- Shortages of U.S. cholera vaccine have raised concerns among some of the nation's top infectious disease doctors, who fear Americans could become highly vulnerable to a public health threat that can spread and kill quickly.
"We got caught flat-footed with monkeypox. This is a wake-up call -- we can't get caught flat-footed again with cholera," Dr. Peter Hotez, co-director of Texas Children's Hospital Center for Vaccine Development, told UPI in a phone interview.
Right now, only one Food and Drug Administration-approved cholera vaccine exists. The U.S. government wants to expand this travel vaccine's use to include children, as well as adults, who head to cholera hotspots.
But it sits on the U.S. drug shortages list and has been unavailable for nearly two years. And no federal vaccine supply exists as backup in case of a disaster-related mass cholera outbreak in this country.
Rising poverty, urbanization, political instability and conflict, along with climate change that spurs natural disasters, are 21st century influences that contribute to cholera outbreaks in other parts of the world, including most recently in Haiti, said Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine.
"We'll see more cases of cholera, monkeypox and coronavirus-like illnesses" globally, Hotez said, citing his 2021 book, Preventing the Next Pandemic.
He added: "When epidemics occur, they're quite explosive, and a lot of people can perish very quickly. You can't wait six months for a company to gear up. ... This is the problem with not adequately stockpiling this [cholera vaccine in the United States], and nobody is looking [at the issue from] an aerial view."
Surges during disasters
Cholera, a severe diarrheal illness caused by the bacterium Vibiro cholerae, may surge in the wake of man-made or natural disasters in areas that lack clean water, adequate hygiene and proper sanitation.
Worldwide, about 1.3 million to 4 million people develop cholera annually, and 21,000 to 143,000 die from it, according to the Centers for Disease Control and Prevention.
The CDC says cholera rarely occurs in the United States, though it was common in the 1800s, because its spread was basically eliminated by modern water and sewage treatment systems.
Yet, the United States is not immune to a problem that constantly ravages so many countries, Hotez said. He noted, for example, that the Texas Gulf Coast, where he lives, could be vulnerable to a cholera outbreak after a hurricane.
"So," Hotez said, "I think it's shortsighted the U.S. government doesn't provide stockpiling [of cholera vaccine]. ... The U.S. needs to catch up with more stockpiling than it currently does."
Nearly all cholera cases reported in the United States arise from international travel, according to the CDC. But when outbreaks occurred in countries near the United States, such as Haiti in 2010, the number of U.S. cholera cases increased. Imported, contaminated seafood also has caused infections.
Globally, an emergency stockpile of oral cholera vaccine was established in 2013 by the World Health Organization's International Coordinating Group and partners.
Since the stockpile's creation, WHO spokeswoman Amna Smailbegovic told UPI, more that 123 million doses have been shipped to 23 countries -- from Bangladesh to Zimbabwe.
After a production increase, the amount of cholera vaccine shipped from the global stockpile rose to 27 million doses in 2021, up from 200,000 doses in 2013, according to WHO.
"All countries are eligible to request vaccines from the global stockpile. However, the risk of a cholera outbreak in high-income countries is very low, so we do not expect this to be the case," WHO said in an emailed statement.
Not tested in U.S.
However, Shanchol and Euvichol-Plus, the two-dose cholera vaccines currently available for mass vaccination campaigns through WHO's global stockpile, were not tested or made in the United States, which experts say the FDA prefers.
CDC spokeswoman Candice Hoffmann underscored the United States' "strong and reliable drinking water systems, adequate sanitation, hygiene and sewage infrastructures" in an emailed statement to UPI on Wednesday.
"In the unlikely event such an outbreak [of cholera] were to occur, CDC would work closely with FDA to seek emergency use licensing for Shanchol and Euvichol-Plus cholera vaccines using data from its usage overseas," Hoffman said.
To allow emergency use authorization, the FDA said it thoroughly evaluates available safety, effectiveness and manufacturing quality information -- a process that may hamper fast response to a public health emergency.
When Pfizer Inc. sought permission for emergency use of its COVID-19 vaccine at the end of 2020, for example, the process took three weeks.
To date this year, 23.5 million doses of cholera vaccine have shipped from the global stockpile, another 8 million doses required for the second dose of the two-dose regimen are pending shipment and more requests are under review, WHO said.
No vaccine in stockpile
By contrast, there isn't a single dose of cholera vaccine in the U.S. Strategic National Stockpile in case of outbreaks, spokeswoman Dawn Young told UPI in an email. This stockpile distributed ventilators and personal protective equipment at the peak of COVID-19, and stores two types of monkeypox vaccine.
The only cholera vaccine approved by the FDA, Vaxchora, has been on the FDA's national drug shortage list for well over a year. And until 2016, when Vaxchora received FDA's go-ahead for use in adults ages 18 through 64, no cholera vaccine had been available for decades for U.S. travelers are risk.
Maryland-based Emergent BioSolutions, which manufactures Vaxchora, told UPI its last batch of the one-dose oral cholera vaccine for U.S. international travelers had been shipped in December 2020.
"Given the unprecedented impact and halt in global travel during the pandemic, we proactively decided to discontinue production of Vaxchora ... [but] continued to diligently monitor travel health trends in preparation for production ramp-up," Jonathan Wong, Emergent Travel Health's general manager and global vice president, said in an email.
Emergent told UPI it resumed Vaxchora's production "in third quarter 2022," but won't have more supply available until early 2023. The vaccine, which costs about $300 per dose, is made at Emergent's plant in Bern, Switzerland.
Emergent -- the target of a congressional probe into the manufacture of COVID-19 vaccines -- said it plans to produce a supply of cholera vaccine "that will meet full year (2023) forecasted demand."
The call for storing a cholera vaccine In the United States dates back more than a decade.
In 2010, Hotez, Dr. Matthew Waldor and Dr. John D. Clemens co-authored a New England Journal of Medicine article that urged creation of a national cholera vaccine stockpile as a "humanitarian and diplomatic resource."
That never materialized, though WHO's global stockpile began a few years later.
Waldor, a professor of medicine at Brigham and Women's Hospital and Harvard Medical School, told UPI in a telephone interview that cholera remains problematic in many parts of the world, but there's been "just the occasional imported case" domestically over the past 20 years that hasn't led to outbreaks.
Cholera is "usually treatable" with fluids and antibiotics, he said, describing the risk to most U.S. international travelers as "very low," aside from aid and healthcare workers, "so it's not a disaster there's not enough cholera vaccine for travelers."
But Waldor said "it's OK [for U.S.-based international travelers] to be super safe and get it [cholera vaccine], and conceded he may be "overly sanguine" about the U.S. cholera vaccine gap.
"Out of an abundance of caution, it might be good to have some in the stockpile, but I don't think there's a major risk for cholera in the United States," he said.
Waldor underscored the overall importance of cholera vaccines, noting that his laboratory plans to begin a phase 1 clinical trial of its own vaccine candidate, probably in November in Boston.
He said he anticipates his vaccine, if proven safe and effective, will join the global stockpile -- and be distributed and manufactured in countries that need it the most.