COVAX, the global project to share COVID-19 vaccines, and the African Union have declined options to buy additional doses of Moderna's MRNA.O shot, as developing nations struggle to allocate supplies.
The global alliance did not exercise the option for 166 million doses of the shot for the third quarter of 2022, as well for 166 million doses in the fourth quarter, which expired on April 1, a Moderna spokesperson said.
COVAX, which is backed by Gavi, the World Health Organization and the Coalition for Epidemic Preparedness Innovations, is struggling to place more than 300 million doses, Reuters reported in February.
Moderna and Gavi have agreements for up to 650 million doses of the company's vaccine to be made available to COVAX participants through 2021 and 2022.
A Gavi spokesperson, who earlier confirmed the development, said the discussions with Moderna are part of "regular decision-making process on exercising options outlined in our advance purchase agreements with manufacturers".
COVAX has picked up the pace of supplies after struggling to acquire shots last year, delivering about 1.40 billion doses to 144 countries as of April 1.
As supply and donations ramped up, some poorer nations are, however, facing hurdles such as gaps in cold-chain shortage, vaccine hesitancy and a lack of funds to support distribution networks.
"We are in conversations with manufacturers ... to align with magnitude and timing of country needs," the Gavi spokesperson said.