"The objective is to make medicines, vaccines and diagnostics available as rapidly as possible to address the emergency," the WHO said in a statement.
WHO Assistant Director-General Mariangela Simao said on Friday it was important to have more vaccines available because of supply problems for other shots, including from India, a main source of vaccines for the global COVAX vaccine sharing programme. India has restricted exports because of a crisis of infections.
Moderna announced this week an expansion plan for its production network to boost its capacity to up to 3 billion doses in 2022.
The WHO's Strategic Advisory Group of Experts on Immunization (SAGE) already in January had recommended Moderna's vaccine for all age groups 18 and above.
Pfizer (PFN.N) and its German partner BionTech's (22UAy.DE) shot, also an mRNA vaccine like Moderna's, was the first vaccine to get a WHO emergency use listing in the final hours of 2020.
Since then, the WHO has added vaccines from Astrazeneca-SK Bio, Serum Institute of India and Johnson & Johnson (JNJ.N) vaccines to the list.
The Geneva-based health organization is still considering COVID-19 vaccines from Sinopharm (1099.HK) and Sinovac (SVA.O) following an extended review, with decisions due by the end of next week.