Until the CDC finally relaxed its guidance last week, the Biden administration had been facing a steady drumbeat of criticism for failing to convey the reality: vaccines work, and mask use outside—especially by vaccinated people—might be overkill. But a new report released by the CDC on Wednesday suggests that while vaccinations have helped massively reduce COVID-19 deaths, and will continue to offer robust protection and ease the way back to normalcy, Americans risk relaxing their personal behavior too quickly. Specifically, the agency released a set of models projecting COVID-19 outcomes based on varying levels of vaccination and what it calls non-pharmaceutical interventions, a.k.a. masks and social distancing. It found that easing up too quickly on the latter, even with vaccines rolling out, may produce surges in cases, hospitalizations, and deaths in the coming months.

The top-line implications of the report, it should be noted, are positive: the vaccines are having a huge impact, and the models anticipated a major drop in cases come July. They also anticipated relatively modest death increases, thanks to the vaccine. And the models’ conclusion that cases would spike this spring, even with high vaccination and moderate safety-measure use, also seems to be belied by declining real-world cases recently.

Still, the report warns about variants and pockets of low vaccination sparking surges, echoing expert concerns about uneven vaccine acceptance nationwide. And it suggests that our days of worrying about masks and social distancing are not close to over just yet.