Yesterday I pointed out How Rapidly ‘First Doses First’ Came to Britain. The United States is also moving in that direction but more slowly. First we ended holding second doses in reserves. Now the CDC has new policies:
CNBC: The Centers for Disease Control and Prevention quietly changed its guidance on Covid-19 vaccine shots, saying it’s now OK to mix Pfizer’s and Moderna’s shots in “exceptional situations” and that it’s also fine to wait up to six weeks to get the second shot of either company’s two-dose immunization.
We will see what happens if new variants start to takeoff in the US, as seems likely, and as the number of people immunized starts to slow as we move from first does to having to vaccinate people for the second dose. More second doses means fewer resources for first timers. Biden’s 100 million in 100 days, for example, was already under-ambitious but it’s not even 100 million people it’s 100 million doses or only about 67 million people given that some will be in line twice.