Cholera: WHO rations vaccines to preserve stocks amid rising outbreaks
BMJ 2022; 379 doi: https://doi.org/10.1136/bmj.o2528 (Published 21 October 2022) Cite this as: BMJ 2022;379:o2528
Countries confronting outbreaks of cholera will have to administer half the recommended doses of vaccines because a global resurgence is exhausting international stockpiles, the World Health Organization announced on 19 October.
The International Coordinating Group, which organises global supplies of emergency vaccines, will now administer a single dose instead of two, as the number of jabs available is dangerously low. The group’s “exceptional decision” reflected the “grave state of the cholera vaccine stockpile,” WHO said in a statement.1
Tedros Adhanom Ghebreyesus, WHO director general, told a press conference in Geneva that halving the vaccine doses would reduce the level of immunity in people getting vaccinated against the bacterial disease but that the organisation was left with no choice, as poverty and climate change were fuelling a global resurgence of cholera.
“The current wave of outbreaks is putting unprecedented pressure on the stockpile,” he said. “As a result, the four agencies have decided to suspend the two dose strategy in favour of a one dose strategy so that more people receive some protection from limited stocks.”
Four agencies make up the International Coordinating Group: WHO, Médecins Sans Frontières, Unicef, and the International Federation of Red Cross and Red Crescent Societies.
On average fewer than 20 countries reported outbreaks in the past five years, but 29 have reported cholera cases since January. WHO said that the rise was “unprecedented” and that cases were likely to be an undercount because of stigmatisation of the disease.
Poverty and war
Many factors—including floods, droughts, conflict, and population movement—are making cholera more prevalent, the UN organisation has warned. Cholera spreads through contaminated water or food, so the disease thrives in times of acute poverty or war when there is little access to sanitation.
More than 10 000 suspected cases of cholera were reported in Syria, which is in a state of civil war, in the six weeks to 6 October.2
In Haiti, escalating gang violence and a humanitarian crisis led to the disease returning this month for the first time in three years.3 This came just as the Caribbean country was applying for cholera-free certification. Since the disease re-emerged 725 cases and 23 deaths have been recorded, said Haiti’s health ministry, including 14 deaths in the national penitentiary.
Moha Zemrag, Doctors Without Borders’ deputy head of mission in Haiti, told The BMJ that the new cases reported each day continued to increase. A cholera outbreak in 2010 took nine years to stamp out and killed 10 000 Haitians.
Cholera is becoming not just more prevalent but more deadly too. The acute diarrhoea it causes can be fatal in places with no access to fluid or antibiotics. The fatality rate this year was almost three times that of the past five years, WHO officials said.
Halving the dose
Administering only a single dose of the vaccine “has proven to be effective to respond to outbreaks, even though evidence on the exact duration of protection is limited, and protection appears to be much lower in children,” WHO said in its statement.
Usually, a second dose is administered within six months after a single dose, offering immunity against infection for three years. A single dose of the vaccine will offer lower levels of immunity and the duration of protection will be shorter, WHO has said, but it lacked data on precisely how much.
Michael Ryan, director of WHO’s health emergencies programme, told the Geneva press conference, “It’s a sad day for us to have to go backwards to a one dose strategy that is life saving.” He criticised a lack of support from richer nations, which he said would not face the same scarcity if they were directly affected.
WHO says that 36 million vaccine doses are forecast to be produced this year, but 24 million have already been shipped, and eight million more have been allocated for emergency vaccination campaigns. Only four million jabs remain in the stockpiles, and all producers are operating at maximum capacity, it advises, so stretching them further around the world is the only way to avoid choosing which countries receive lifesaving protection and which do not.
“This is clearly less than ideal, and rationing must only be a temporary solution,” said Tedros. “In the long term we need a plan to scale up vaccine production as part of a holistic strategy to prevent and stop cholera outbreaks.”