GENEVA - The World Health Organization (WHO) on Thursday called on the world's 20 richest nations, holding a summit next week, to step up donations of COVID-19 doses to the global south where vaccinations lag.

"The @g20org countries must fulfil their dose-sharing commitments immediately," WHO director-general Tedros Adhanom Ghebreyesus told a news briefing.

Gordon Brown, WHO ambassador for global health financing, said that if the world's richest countries cannot mobilise for a vaccine airlift to developing countries, an epidemiological and economic "dereliction of duty will shame us all".

There is still a shortfall of 500 million vaccine doses to reach WHO's 40% vaccination target in all countries by year-end, while 240 million doses are lying unused in the West, Brown said.

(Reporting by Stephanie Nebehay in Geneva and Sri Kalyani Manojna Maddipatla in Bengaluru; Editing by Jon Boyle) ((Stephanie.Nebehay@thomsonreuters.com; +41 58 306 2161; Reuters Messaging: stephanie.nebehay.thomsonreuters.com@reuters.net; twitter @StephNebehay))