The Centers for Disease Control and Prevention (CDC) pressured U.S. regulators to clear COVID-19 boosters without clinical trial data, according to newly released emails.

CDC officials relayed to counterparts at the U.S. Food and Drug Administration (FDA) in early August 2021 that they wanted authorization for Moderna and Pfizer boosters as data began showing that the vaccines weren't working as well as initially promoted.

The conversation took place on a call that was described by Dr. Phil Krause, a top FDA official, to several other FDA workers.

"Take a deep breath before reading this next paragraph. On that call, the CDC evidently stated that they will assemble all the data they are aware of on third dosing in this setting and send it to us in the hope that we will (very soon) authorize the third dose for immunocompromised as part of the EUA," Krause wrote in the Aug. 5, 2021, email.

EUA stands for emergency use authorization.

All of the COVID-19 vaccines were authorized under emergency conditions at that time.