The U.S. Food and Drug Administration fought back on Friday against what it calls “the proliferation of misinformation” by Florida’s Surgeon General Joseph Ladapo about the safety of COVID-19 vaccines.

In a letter earlier this month to the FDA, Ladapo had questioned the agency’s drug approval and raised alarms about what he sees as the risk of potential cancer posed by COVID-19 mRNA vaccines. Ladapo, the leader of Florida’s health department, said he believed the drug delivery system used by mRNA vaccines could be an “efficient vehicle for delivering contaminant DNA into human cells.”

But a top researcher with the FDA released a public response to Ladapo on Friday saying the Surgeon General’s scientific assertion regarding the cancer risk is “implausible.”

“These questions (raised by Ladapo) are designed to scare people rather than investigate true science,” she said. “What we do know is that COVID continues to kill thousands of people every month in the U.S. I think he is doing a disservice to the people of Florida by trying to scare them into not getting a vaccine that can be lifesaving.”