Oct 19, 2022 - World

WHO switches to one-dose cholera vaccine strategy as outbreaks spread

A Yemeni child receives the oral cholera vaccine in March.

A Yemeni child receives the oral cholera vaccine in Taizz, Yemen, on March 5. Photo: Abdulnasser Alseddik/Anadolu Agency via Getty Images

The World Health Organization will temporarily switch from a two-dose cholera vaccine regimen to a one-dose approach due to an "unprecedented rise in cholera outbreaks worldwide" and a shortage in vaccine supply, the global health body said Wednesday.

Driving the news: Twenty-nine countries including Haiti, Syria, Lebanon and Malawi have reported outbreaks so far this year. Fewer than 20 had outbreaks on average in the previous five years, the WHO said.

What they're saying: "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 WHO said in a statement.

  • The world health body acknowledged that although the "temporary interruption of the two-dose strategy will lead to a reduction and shortening of immunity," the benefit of a one-dose approach "still outweighs no doses."
  • Daniela Garone, the international medical coordinator of Doctors Without Borders/Médecins Sans Frontières (MSF), called Wednesday's move a "last resort decision" in order "to avoid making the impossible choice of sending doses to one country over another."
  • MSF is part of the global group that manages and coordinates vaccine supply during outbreaks, along with the WHO, UNICEF and the International Federation of Red Cross and Red Crescent Societies.

The big picture: Haiti has confirmed at least 32 cholera cases and 18 deaths from the disease as of Oct. 9, though officials warn the true numbers may be much higher.

  • Syria's outbreak has now spread to Lebanon, which has recorded 18 confirmed cases, including two probable deaths. It's Lebanon's first cholera outbreak since 1993, per the WHO.
  • Over 100 cholera-related deaths have been reported in Malawi, Reuters reported earlier this month.
  • Other countries, including Pakistan and Cameroon, have reported new outbreaks this year.

State of play: The rise in outbreaks has strained the already "extremely limited" global supply of cholera vaccines, the WHO said.

  • About 24 million of the 36 million doses of the vaccine that are expected to be produced this year have already been shipped for preventive and reactive campaigns, the UN said.

The bottom line: The switch to a one-dose strategy 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 said.

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