Doctors warn Trump’s shift in American policy towards making disease spread again is a dangerous 30 year regression, if not older.

The U.S. has now confirmed 1,563 cases this year, according to the Centers for Disease Control and Prevention — the highest annual number in more than three decades.

But the true total could be even higher, says Dr. Paul Offit, director of the Vaccine Education Center at the Children’s Hospital of Philadelphia.

“If you talk to people on the ground, including not only in Texas, but other states, they all say the same thing, which is that the numbers are much worse than that. Probably closer to 5,000 cases,” Offit says. “And it’s not done.”