An international cholera vaccine shortage has forced a temporary shift to a one-dose strategy from the usual two in campaigns to fight numerous outbreaks, according to the World Health Organisation, which said the change in strategy will allow for the doses to be used in more countries during an unprecedented rise in infections worldwide.
The UN health agency said the “strained global supply of cholera vaccines” had pushed the International Co-ordinating Group (ICG), which manages emergency supplies of vaccines, to suspend the two-dose regimen, reports The Citizen.
So far this year, 29 countries have reported cholera cases, including Haiti, Syria and Malawi, compared with fewer than 20 nations that reported such outbreaks in total over the previous five years.
“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,” WHO said.
WHO and other members of the ICG – Doctors Without Borders (MSF), UNICEF and the Red Cross – said a one-dose strategy for cholera vaccines was effective in response to outbreaks, but there was only limited evidence on the exact duration of protection, which appeared to be much lower in children especially.
With two doses, when the second dose is given within six months of the first, immunity against infection lasts for three years. ICG manages a global stockpile of oral cholera vaccines, but of the 36m doses forecast to be produced this year, 24m have already been shipped for preventive and reactive campaigns.
An additional 8m doses have been approved by ICG for a second round of emergency vaccination in four countries.
One reason for the growing concern about the situation is that the maker of one of only two cholera vaccines for use in humanitarian emergencies, an Indian subsidiary of French pharmaceutical giant Sanofi, has said it would halt production by the end of the year.
The Citizen article – Cholera vaccine shortage forces move to one-dose strategy – WHO (Open access)
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