ANN ARBOR, MI (MPRN)-- Thirty-three Michigan counties now have "substantial" or "high" COVID transmission rates, according to the CDC's data.
That's the threshold where the federal government encourages even fully-vaccinated people to wear masks indoors.
It's a sign of how quickly the Delta variant may be spreading in the state: last week, only six counties were considered higher risk.
Doctor Joel Fishbain is Beaumont's Medical Director for Infection Prevention. He says with new evidence that vaccinated people may be able to transmit the delta variant, the greater the risk is of the virus continuing to spread and evolve.
"I'm concerned that the next variant might escape previous immunity and might escape vaccination. That's why we have to vaccinate everybody as quickly as we can try to prevent any transmission."
Fishbain says he's personally encouraging everyone, regardless of where they live, to return to universal masking indoors.