The U.S. Centers for Disease Control and Prevention is coming in for criticism over its most recent change of guidance on masks in the fight against COVID-19.

Some of these complaints are justified, some unfair. The main thing is to keep the focus on what matters most — getting people vaccinated as quickly as possible. Confusion over the CDC guidance risks becoming a distraction from that overriding priority.

The agency's recommendations on masking changed abruptly at the end of last month. Previously officials had said that vaccinated people didn't need to wear masks because they were well protected against the virus and unlikely to spread it to others. They now recommend that fully vaccinated people "wear a mask in public indoor settings in areas of substantial or high transmission" — which, as the agency points out, is most of the country.

Some jurisdictions promptly ordered masks to be worn in offices and other indoor settings regardless of whether some, most, or all of the people inside had gotten their shots. The CDC should have been more cautious in May when it said that vaccination makes masks unnecessary. But officials shouldn't be criticized for changing their recommendations. Many aspects of COVID-19 and its variants still aren't fully understood, and the pandemic keeps evolving. As the science changes, the advice that's based on it needs to change as well.

New evidence, as the CDC rightly points out, suggests that the delta variant can be more readily passed along by vaccinated people. The risks posed by the new strain should be taken seriously. But getting a shot still greatly reduces the risk of infection, and the relatively small number of vaccinated people who do get infected typically suffer only mild symptoms. If you're vaccinated and the people around you are vaccinated, the danger posed by the delta variant is slight.

The new information argues for every effort to encourage and (within limits) require people to get their shots. But employers that do insist their staff get vaccinated don't need to tell them to stay masked as well. Imposing this requirement indiscriminately could be taken to mean that the vaccines don't work as hoped, that even a fully vaccinated staff is still in danger, and that "better safe than sorry" means postponing the return to life as normal, perhaps indefinitely, whether people are protected or not.

This approach might actually worsen vaccine hesitancy. In other words, "better safe than sorry" involves costs, and a balance has to be struck. The best course is for employers and businesses to insist that staff and customers shouldn't share indoor spaces unless they've been vaccinated.

Where this policy has been implemented, people who aren't especially at risk (due to being immunocompromised, for instance) shouldn't be required to wear masks — not, at any rate, given the current state of knowledge. Stronger vaccine rules are the best response to the delta variant — and the CDC isn't helping if it lets that message get muddled.