The WHO announced Friday it had approved a new, simpler version of an existing oral cholera vaccine, which should help increase the number of available doses as global cases surge.

The Euvichol-S vaccine is a simplified formulation of Euvichol-Plus, with fewer components -- which should allow for larger volumes to be produced faster.

It is produced by EuBiologics, and the World Health Organization has already given its green light to the South Korean firm's Euvichol and Euvichol-Plus vaccines.

The WHO said the new vaccine has a similar efficacy rate.

"The new vaccine is the third product of the same family of vaccines we have for cholera in our WHO prequalification list," said Rogerio Gaspar, director of the UN health agency's Department for regulation and Prequalification.

"The new prequalification is hoped to enable a rapid increase in production and supply which many communities battling with cholera outbreaks urgently need."

Some 473,000 cholera cases were reported to the WHO in 2022 -- double the number from 2021 -- and preliminary data indicates that more than 700,000 cases were reported last year.

Even though the global supply of oral cholera vaccines ballooned 18-fold between 2013 and 2023, the surging demand has created a global shortage.

Currently, 23 countries are reporting cholera outbreaks. The most severe impacts are being felt in the Comoros, the Democratic Republic of Congo, Ethiopia, Mozambique, Somalia, Zambia and Zimbabwe.

In a joint statement, the Gavi vaccine alliance and the UN children's agency UNICEF said the move would help produce "more volumes of vaccine, faster, and at a lower cost".

They said it would help increase the global stockpile from 38 million doses in 2023 to around 50 million this year.

The WHO move "represents a lifeline for vulnerable communities around the world", said Derrick Sim, Gavi's vaccine markets chief.

"The approval of this new product could not have come at a more important time given the acute upsurge of cholera outbreaks we are seeing worldwide."

The liquid vaccine has a 24-month shelf life.

Gavi and UNICEF said EuBiologics was currently the only oral cholera vaccine supplier to the global stockpile, though other manufacturers were expected to have products available in the coming years.

Cholera is an acute intestinal infection that spreads through food and water contaminated with the bacterium vibrio cholerae, often from faeces.

It can kill within hours when not treated, but immediate access to treatment saves lives, the WHO says.