"I think that the AstraZeneca vaccine from a standpoint of efficacy is a good vaccine, and if the safety issue gets straightened out in the European Union... the efficacy of that vaccine is really quite good," he told BBC radio on Tuesday.
He also attacked Fauci's ability to throw a baseball, described him as "king of the flip-flops," and said "Birx was a terrible medical advisor, which is why I seldom followed her advice."
Earlier this month the US Centers for Disease Control and Prevention (CDC) issued new guidelines urging schools to reopen safely and as soon as possible.
Though concern has grown over variants of the virus, especially those that appear to spread more easily and render current shots less potent, Fauci sounded a hopeful note on whether another surge was coming.
Globally, Pfizer and BioNTech aim to make 2 billion doses of the COVID-19 vaccine this year. Pfizer's chief financial officer told Reuters earlier this month that it had recently doubled the size of the batches of its vaccine and increased the number of batches it was producing.
National Australia Bank's Ray Attrill said that traders were a long way from worrying about the possible negative aspects of Biden's presidency, such as tax hikes and re-regulation.
"The idea that you can get up here and talk about what you know. What the evidence, what the science is, and know that's it -- let the science speak -- it is somewhat of a liberating feeling."
More than a million Americans have received the first dose of their Covid-19 vaccines, a milestone in the biggest immunization drive in US history, but officials admitted the pace of rollout was slipping behind schedule.