GENEVA—The World Health Organization has given the go-ahead for emergency use of Moderna’s COVID-19 vaccine. The mRNA vaccine from the U.S. manufacturer joins vaccines from AstraZeneca, Pfizer-BioNTech, and Johnson & Johnson in receiving the WHO’s emergency use listing. Similar approvals for China’s Sinopharm and Sinovac vaccines are expected in the coming days and weeks, WHO has said. The greenlight for Moderna’s vaccine, announced late Friday, took many months because of delays WHO faced in getting data from the manufacturer. Many countries without their own advanced medical regulatory and assessment offices rely on the WHO listing to decide whether to use vaccines. U.N. children’s agency UNICEF also uses the listing to deploy vaccines in an emergency like the pandemic. The announcement isn’t likely to have an immediate impact on supplies of Moderna’s vaccine for the developing world. The company struck supply agreements with many rich countries, which have already received millions …