The United States is planning to send a total of 4 million doses of the AstraZeneca vaccine to Mexico and Canada. Many countries have been asking for help from the US, which is sitting on stockpiles of AstraZeneca doses. The vaccine is not approved for use in the US. The announcement from the Biden administration marks the first time the US is exporting coronavirus vaccines. The World’s Latin America correspondent Jorge Valencia, in Mexico City, has more.