COVAX, the global project to share COVID-19 vaccines, and the African Union have declined options to buy additional doses of Moderna's 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…