The World Health Organization on Monday granted emergency authorization to the Oxford-AstraZeneca coronavirus vaccine.

Why it matters: WHO's authorization "should trigger the delivery of hundreds of millions of doses to countries that have signed up for the U.N.-backed COVAX effort, which aims to deliver vaccines to the world’s most vulnerable," AP writes.

• This is only the second vaccine to get authorization from the agency, following an emergency authorization for the BioNTech-Pfizer vaccine in December.
• The COVAX initiative, with more than 180 nation participants, is the global effort from the World Health Organization and other groups to ensure that every country has access to COVID-19 vaccines.

Details: WHO authorized two versions of the AstraZeneca vaccine — found to be approximately 63% effective.

• Due to their "easy storage requirement," the agency found them to be suitable for low- and middle-income nations.
• The vaccines will be produced by AstraZeneca-SKBio in Korea and the Serum Institute of India.

The big picture: The authorization comes days after WHO recommended the vaccine for adults ages 18 and up, including those older than 65.

• People younger than 18 should not take the vaccine, as additional research results are pending.
• WHO also recommended that "priority be given to health workers at high risk of exposure and older people."

What they're saying: "Countries with no access to vaccines to date will finally be able to start vaccinating their health workers and populations at risk, contributing to the COVAX Facility’s goal of equitable vaccine distribution," said Mariângela Simão, WHO assistant-director general for Access to Medicines and Health Products.