During the conversation, Slavitt asked Walensky whether people who had received a Johnson & Johnson Covid vaccine should consider getting a follow-up shot from one of the mRNA vaccines, either Moderna’s or Pfizer’s. The J.&J. vaccine has officially been a single-shot vaccine, unlike the others, and also seems to be somewhat less effective. Understandably, many J.&J. recipients have wondered whether they should get a second shot from one of the mRNA vaccines. Some doctors and scientists, finding the evidence persuasive, have already done so themselves.
Walensky began her answer by restating official C.D.C. policy: “We’re not currently recommending it.” But then she added the fuller truth: “I’ll tell you what we do know, and some places where I think people might veer from standard guidance.”
She explained that the AstraZeneca vaccine — available in many other countries — was very similar to the J.&J. vaccine. And some people who had received a single shot of AstraZeneca decided to follow it up with an mRNA shot. There was not much data about how well that worked, Walensky said, but it was probably safe and she understood why some people might choose to do so.
At this point, Slavitt put the question in personal terms: “If someone you knew said, ‘I’m going to get the mRNA vaccine because I’m just too nervous,’ you wouldn’t lay down in the tracks necessarily and say, ‘This is a huge mistake’?”
“Not with what I’ve seen so far,” Walensky replied. If you chose to take a mix-and-match approach, she added, “you have to be willing to take the risk-benefit there.”