Single-dose approach: Global cholera outbreak leads to vaccine crunch

Amid a rapid spike in the number of cholera cases globally, the International Coordinating Group (ICG) has decided to temporarily suspend the standard two-dose vaccination regimen. The group, which is responsible for distributing emergency oral cholera vaccines, has decided to opt for a single-dose approach.

World Health Organisation (WHO) and its partners, which includes UNICEF, the International Federation of Red Cross and Red Crescent Societies, in a statement on October 18 said that one dose of vaccine has proven effective in stopping outbreaks, even though evidence on the exact duration of protection is 'limited' and appears to be lower in children.

The pivot in strategy will allow for the doses to be used in more countries, at a time of unprecedented rise in cholera outbreak worldwide, WHO added.

According to the WHO report, 29 countries, including Haiti, Malawi and Syria, are facing large outbreaks since the beginning of the year. In comparison, fewer than 20 countries on average reported outbreaks, in the past five years. 

The report added that the global trend is moving towards numerous and more severe outbreaks, because of floods, droughts, population movements, and other factors, which limit access to clean water and increase the risk of cholera outbreaks.

This decision is an attempt to avoid making the impossible choice of sending doses to one nation over another, said Dr Daniela Garone, international medical coordinator at Doctors Without Borders, one of WHO's partners in managing the global cholera vaccine stockpile, the AP reported.

The current supply of cholera vaccines is extremely limited. Out of the total 36 million doses forecast to be produced in 2022, 24 million doses have already been shipped for preventative  (17 per cent) and reactive (83 per cent) campaigns. An additional eight million doses were approved by the ICG for the second round for emergency vaccination in four countries.

The report also highlights the benefit of supplying one dose outweighs no doses. Even though the temporary suspension in the two dose regimen can lead to a reduction and shortening of immunity, the decision will allow more people to be vaccinated and provide them the protection in the near term. 

Saying that cholera can sometimes kill within a day, WHO Director -General Tedros Adhanom Ghebreyesus warned about the unprecedented pressure which is being put on the limited vaccine supply amid the outbreaks. Tedros suggested that the authorities should aim to scale up vaccine production.

WHO in its report also mentioned that since the vaccine manufacturers are producing at their maximum capacity, there is no short-term solution to increase the vaccine production.