Note: *Scientists warn against directly comparing the efficacy of the vaccines because each trial was run differently. / **Average results. One dosing regimen saw 90% efficacy, the other, 63%. / ***The US government will purchase vaccines and distribute them to the public for free. / ****Moderna is part of the COVAX project, but its CEO has said the company has not "quite aligned with them on how many doses and when those doses would be available," according to Axios.