The World Health Organization cleared AstraZeneca Plc’s COVID-19 vaccine for emergency use, adding its official approval to a shot that’s expected to speed up inoculations in developing countries.

The WHO validated two versions of the vaccine, produced with SK Bioscience Co. in South Korea and the Serum Institute of India.

The formal approval follows a recommendation by the WHO Strategic Advisory Group of Experts on Immunization to allow the vaccine to be administered to all adults over 18. That guidance differs from the approach taken by some European Union countries that have restricted its use in the elderly, citing insufficient trial data.

Many developing countries are waiting to give their first shots as wealthier countries have already inoculated millions of residents.

The WHO’s authorization is needed for the global Covax initiative to send vaccines to participating countries, in order to ensure a product’s safety and efficacy for those that might not have the resources to make the assessments themselves.

The Astra vaccine, developed with the University of Oxford, was previously cleared by regulators in the EU, the U.K. and other countries.