How many times is Rochelle Walensky going to be embarrassed by the Biden administration publicly accusing her of jumping to conclusions about COVID? It happened in early February, when Walensky insisted that teachers didn’t need to be vaccinated for schools to reopen safely. That made the White House and its patrons in the teachers unions anxious so Jen Psaki walked it back, telling reporters that the head of the CDC was speaking merely in her “personal capacity.” The agency itself was still reviewing the data and would issue a formal judgment at a later date.

But that episode seems mild compared to Walensky excitedly telling a national TV audience a few days ago that those who’ve been immunized don’t carry the virus, only to have her own deputies scramble to try to unwind that message as it got picked up across American media.

Either Walensky really is reckless in her pronouncements about what the science supports, in which case she needs to be kept away from microphones or replaced, or she’s telling the truth but the hyper-cautious public-health brain trust in the administration thinks the public isn’t ready to hear it. Tell parents that schools can reopen without waiting for teachers to be vaxxed and they might demand reopening ASAP. Tell vaccinated people that they can get back to normal sans masks because they don’t transmit the virus and the unvaccinated might take that as a cue to start getting back to normal too. Whatever the answer is, we have a major problem with our COVID messaging if the head of the CDC and Team Biden’s other mouthpieces are consistently on different pages.

Here was Walensky two days ago:

CDC Director Dr. Rochelle Walensky: “Our data from the CDC today suggest that vaccinated people do not carry the virus.” pic.twitter.com/9W1SHecSEm

— The Recount (@therecount) March 30, 2021

And here was her own CDC last night:

“Dr. Walensky spoke broadly during this interview,” an agency spokesman told The Times. “It’s possible that some people who are fully vaccinated could get Covid-19. The evidence isn’t clear whether they can spread the virus to others. We are continuing to evaluate the evidence.”…

The data suggest that “it’s much harder for vaccinated people to get infected, but don’t think for one second that they cannot get infected,” said Paul Duprex, director of the Center for Vaccine Research at the University of Pittsburgh…

“There cannot be any daylight between what the research shows — really impressive but incomplete protection — and how it is described,” said Dr. Peter Bach, director of the Center for Health Policy and Outcomes at Memorial Sloan Kettering Cancer Center in New York.

“This opens the door to the skeptics who think the government is sugarcoating the science,” Dr. Bach said, “and completely undermines any remaining argument why people should keep wearing masks after being vaccinated.”

I want to side with Walensky on this because it’s true that the great majority of vaccinated people don’t get infected and it’s encouraging to see a public-health bureaucrat for once overselling the vaccine instead of underselling it. But … she is overselling it. There’s no question that a few people who are immunized, even with Pfizer or Moderna, will get infected anyway. We’ve known that since the clinical trials told us that the mRNA vaccines are 95 percent effective. Great! — but not 100 percent. We saw it again in the real-world data out of Israel, which found that the vaccines cut asymptomatic infection by 94 percent, not 100. One of the CDC’s own studies released earlier this week found just three infections among 2,479 vaccinated first responders, an amazing result. But three isn’t zero. Washington state announced two days ago that, out of one million vaccinated people, they’d found 102 cases of infection, which shakes out to .01 percent. Astoundingly effective.

But not perfectly effective. For cripes sake, we’ve had members of Congress test positive after getting their second shots.

It’s just not true that vaccinated people “don’t carry the virus” as a rule, then. You could forgive an average joe for putting it that way as shorthand to express how great the vaccines are. You might even forgive a politician who used that phrase in a fit of exuberance to encourage people to get immunized. The great, great, great majority of vaccinated people don’t carry the virus. But … a few do. And the head of the CDC, one of the highest public authorities on the pandemic, whose words will be amplified by the media and taken to heart by the public, has to account for that by speaking precisely. A few vaccinated people will carry the virus. Every study that’s looked at the question has confirmed that, as far as I’m aware.

I wonder if Walensky just tends to err on the side of optimism in her public pronouncements. Right, I know, she’s the same person who warned of “impending doom” from a new wave of COVID a few days ago, but she said schools could reopen without vaccinating teachers, she updated the guidance for spacing out students in schools from six feet to three feet, and here she was on Rachel Maddow’s show a few nights ago flatly (and falsely) insisting that vaccinated people don’t carry the virus. If she’s signaling that she’ll be aggressive in urging that restrictions on vaccinated people should be lifted soon, that’s great. But the last thing we need from our already muddled public-health messaging is the CDC having to walk back something erroneous that the director said. Do better.