Since the Centers for Disease Control and Prevention first came out with its misguided policy to lift masking requirements in May, I have been calling on it to reverse course. On Tuesday, it did, but the new guidance remains just as confusing and the communication just as muddled.

CDC Director Rochelle Walensky explained in a press briefing that in light of emerging data, the agency is recommending that vaccinated people wear masks indoors again in areas of high covid-19 transmission. Walensky cited unpublished research showing that vaccinated people who become infected with the delta variant carry a similar amount of virus to those who are unvaccinated and infected. This change in the science was the impetus for the new guidance, because it suggests that vaccinated people could be carriers and therefore capable of spreading the coronavirus to family members who are unvaccinated or immunocompromised.

That’s certainly important information for many Americans to know. As the mom of two children too young to be vaccinated, I have already been taking precautions to reduce my risk of being an asymptomatic carrier and unknowingly infecting my kids. I never stopped wearing a mask in grocery stores, hotel lobbies and other indoor, crowded spaces where I don’t know others’ vaccination status. My concern is that the unvaccinated could be a danger to me, and even though I’m well-protected from becoming severely ill myself, there’s still a chance I could contract the coronavirus and bring it back to my vulnerable family members.

On an individual level, the CDC guidance that people in my circumstance mask up is correct. But does it make sense for local governments and businesses to implement mask mandates because of the risk posed by or to the vaccinated? That’s what the new guidance implies, even though it’s contradicted by the CDC’s own data. During the same press briefing, Walensky said the vaccinated are 20 times more protected than the unvaccinated from becoming severely ill, and seven times more protected from having mild symptoms. She made clear that the vast majority of transmission appears to be from the unvaccinated and that “vaccinated individuals continue to represent a very small amount of transmission occurring around the country.”

That leaves many people wondering what’s actually going on here. If the vaccinated aren’t the problem, why are they being punished by having to put on masks again? If most transmission is happening because of the unvaccinated, then why is the CDC saying that the guidance is evolving because the science changed about transmission risk of the vaccinated?

I think the CDC was trying to convey two messages that got tangled up and lost in translation. The first, which I agree with, was an effort to give a warning to individuals who live with vulnerable people. Here, the science really did change. Vaccinated parents with unvaccinated children should know that we have a higher likelihood of spreading the delta variant to our kids than previous variants. We should wear masks in indoor, public spaces not because we are a risk to strangers around us but because we don’t want to get infected and pass the virus on to our children.

The CDC is also trying to urge localities and businesses to reimplement indoor mask requirements given surging coronavirus infections. That’s the right policy, but it’s using the wrong explanation. The vaccinated are not a major source of spread. Even if every vaccinated person puts on a mask, that’s not going to solve things when the vast majority of transmission is by the unvaccinated.

And that is the actual problem that the CDC is trying to solve: It wants to get the unvaccinated to put on masks in indoor spaces. Without proof of vaccination, the only way to reliably to do this is to ask the vaccinated to also don our masks. Relying on the honor system was a big fail, and the best way to curb the current surge is to get everyone to mask up again.

That’s what the CDC should have announced: We need a return to indoor mask mandates not because the vaccinated are suddenly a problem, but because we don’t trust the unvaccinated to voluntarily do the right thing. It’s not a commentary about the effectiveness of the vaccine, or even the trickiness of the delta variant, but rather about the failure of unvaccinated Americans to fulfill their societal obligation to act in the interest of everyone’s health.

When the CDC issued its mask guidance two months ago, it got the science right, but the policy and communication wrong. This has happened again. The Biden administration should make clear that the backsliding of the United States’ pandemic progress necessitated the return of indoor masking. This has happened because of those who choose to remain unvaccinated, and the vaccinated are now paying the price.