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October 20, 2022
A strained global supply of cholera vaccines has obliged the International Coordinating Group (ICG), the body which manages emergency supplies of vaccines to temporarily suspend the standard two-dose vaccination regimen in cholera outbreak response campaigns, using instead a single-dose approach.
In a statement by the World health organisation (WHO), the pivot in strategy will allow for the doses to be used in more countries, at a time of unprecedented rise in cholera outbreaks worldwide.
“Since January this year, 29 countries have reported cholera cases, including Haiti, Malawi and Syria which are facing large outbreaks. In comparison, in the previous 5 years, fewer than 20 countries on average reported outbreaks.
The global trend is moving towards more numerous, more widespread and more severe outbreaks, due to floods, droughts, conflict, population movements and other factors that limit access to clean water and raise the risk of cholera outbreaks.
The one-dose strategy 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. With a two-dose regimen, when the second dose is administrated within 6 months of the first, immunity against infection lasts for 3 years.
“The benefit of supplying one dose still outweighs no doses: although the temporary interruption of the two-dose strategy will lead to a reduction and shortening of immunity, this decision will allow more people to be vaccinated and provide them protection in the near term, should the global cholera situation continue deteriorating.
As vaccine manufactures are producing at their maximum current capacity, there is no short-term solution to increase production. The temporary suspension of the two-dose strategy will allow the remaining doses to be redirected for any needs for the rest of the year.
This is a short-term solution but to ease the problem in the longer term, urgent action is needed to increase global vaccine production.
The WHO however noted that ICG will continue to monitor the global epidemiological trends as well as the status of the cholera vaccine stockpile, and will review this decision regularly.
