As the world’s cholera epidemic is on the rise, there is a shortage of vaccines Science

On October 2, Haiti announced this cholera returned to the country. Memories of the previous epidemic, which killed nearly 10,000 Haitians between 2010 and 2019, remain raw; Now that violent gangs are fighting for control of the country and the health system is in disarray, things could get very bad again.

A few days later, Lebanon reported its first case of cholera since 1993, involving a Syrian refugee and a health worker in the north of the country. More cases could quickly emerge, and health officials fear that Lebanon’s health system, which has been hit by years of financial crisis, will strain under the new burden. Two weeks later, Kenya, where millions have fled the worst drought in decades, also reported its first case of cholera.

The outbreak is part of what the World Health Organization (WHO) is calling an “unprecedented” outbreak of cholera, caused in part by climate change and the downturn caused by the COVID-19 pandemic. Outbreaks have been reported in 30 countries this year, up from an average of less than 20 in the last 5 years. “Outbreaks in more countries and more regions are likely to last longer,” said Daniela Garone, international health coordinator for Doctors Without Borders (MSF). A global shortage of cholera vaccine supplies is forcing health authorities to resort to dietary doses and rethink their control strategies.

Cholera is spread through water or food contaminated with the bacteria Cholera vibrio, causing severe diarrhea and killing an estimated 20,000 to 140,000 people each year. Lack of clean drinking water, poverty, natural disasters, and armed conflict, such as gang violence in Haiti, have exacerbated disease outbreaks.

A few years ago, the prospect of reducing the load seemed bright. A new low-cost vaccine made from inactivated, non-toxin-containing bacteria was approved in 2015; Millions of doses have been added to the international stockpile for emergency use. In 2017, WHO and many international partners launched an ambitious new control strategy It was based on vaccination, improved sanitation, and expanded access to clean drinking water and treatment. It aimed to reduce cholera deaths by 90% by 2030 and eliminate the disease in 20 countries.

Extreme weather caused by global warming is part of the reason for the increased incidence, said Philippe Barbosa, head of the WHO’s Cholera and Diarrhea Epidemiology Unit. Droughts in West Africa and the Horn of Africa, massive floods in Southeast Asia, and cyclones in southern Africa displaced people and destroyed water and sanitation infrastructure. The toll of COVID-19 on the healthcare system has made matters worse. The death rate from cholera in Africa is almost 3% in 2021, Barbosa said, three times higher than in the previous 5 years. “We’ve been investigating why [death rate] was very high, but the reason was the same: delayed access to health care,” he said.

The 36 million doses of vaccine expected to be shipped from stockpiles this year will not be enough. Two doses 2 weeks apart are required for full protection, so the supply covers only 18 million people—”not a lot when you think about it.” [affected] Countries like Bangladesh, Pakistan, Ethiopia and Nigeria,” Barbosa said. Last month, the International Coordination Group, which runs the stockpile of WHO, MSF, UNICEF and the International Federation of Red Cross and Red Crescent Societies, ordered a second dose to extend supplies. Charlie Weller, an immunologist at the Wellcome Trust, said the single-dose strategy had been used successfully in the past, but it was unclear how long the protection would last.

David Sack, an infectious disease expert at Johns Hopkins University’s Bloomberg School of Public Health, is “skeptical” about the decision to skip the second dose instead of delaying it. A clinical trial in Cameroon by Sak et al published this month Giving the second dose 1 year later rather than 2 weeks later increases the immune response. But if the outbreak doesn’t slow down in the coming months, the vaccine supply won’t even allow for the second dose to be delayed. In addition, current WHO guidelines don’t allow more than six months off, Garon said, but that could change. “We wanted to speed up the review of the evidence in this regard,” he said.

Meanwhile, India’s Shantha Biotechnics, which produces 10 percent of the world’s cholera vaccine supply, plans to stop production by the end of 2023. WHO Director-General Tedros Adhanom Ghebreyesus called on Shanta and its parent company Sanofi to reconsider their decision. That would leave just one manufacturer, South Korea’s EuBiologics. The International Vaccine Institute (IVI), a South Korea-based nonprofit that helped develop the low-cost oral vaccine, is working with EuBiologics to increase its production capacity to 80 million to 90 million doses annually, said Julia Lynch, who directs IVI’s cholera program. . . We are also helping a South African company called Biovac to set up a filming facility. project Funded by the Wellcome Trust and the Bill & Melinda Gates Foundation.

But both efforts will take several years. In the near future, countries that have consolidated their multi-year cholera control plans and requested vaccines from stockpiles are likely to receive smaller or later doses than desired, Lynch said. He added that this could lead to other countries not bothering about such plans. “I’m really worried about losing the momentum I’ve gained.”

Barbosa emphasizes that vaccines are the only way to solve the crisis. Cholera is easily treated with oral rehydration solutions if taken quickly. This makes access to primary health care very important. “You don’t need a ventilator or an intensive care unit. God knows what’s going to happen,” Barbosa said. At the same time, countries must continue to work to improve access to clean water and sanitation, he said: “We may have lost the battle, but we have not lost the war.”

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