EMMA FARGE THE COVAX vaccine-sharing scheme hopes to send millions of delayed doses of AstraZeneca's shots to Africa in June and July, but the deployment hinges on a Spanish manufacturing site securing regulatory approval, according to U.N. officials. Africa has been hit by a halt in vaccine exports from India which were due to make up a significant portion of the first phase of the COVAX roll-out. As a result, many recipients including health workers will not receive their second dose of the AstraZeneca shot within the recommended 12-week interval. "The second dose gap is a huge issue," World Health…