The fourth wave of the COVID-19 pandemic, which is fuelled by the Delta variant, may be the last one to hit the U.S., the former chairman of the Food and Drug Administration has said.

Dr. Scott Gottlieb said on CNN Thursday that COVID is on its way to becoming an endemic disease, assuming no new variants emerge. This means that, like the seasonal flu, the virus will always be present in the population but will circulate at low rates.

"I think on the back end of this delta wave, this may be our last major surge of coronavirus before we settle into a more seasonal endemic pattern with this virus," Gottlieb said.

He also praised the Biden administration's vaccine rollout efforts, saying that while the 77% adult vaccination rate isn't ideal, it's still "a remarkable achievement over this time period."

His remarks come just one day after a new model indicated that COVID cases and deaths will drop to levels not seen since the pandemic first hit the U.S. in late March 2020.

The number of new infections has been decreasing, with 135,611 new infections registered on Wednesday and a seven-day rolling average of 131,076, down 14% from four weeks ago. The rate of increase in new coronavirus cases had begun to drop dramatically in recent weeks before beginning to decline last week.

If no new variants emerge, Gottlieb predicts that COVID will become an endemic disease, meaning that it will always be there but spread at low rates, rather than a disease that requires hospitalization.

Gottlieb emphasized he still would like to see the vaccination rate rise.

"We really need to get to around 80% to 85% to have enough vaccination in the population that you start to see case rates decline and the velocity of spread start to slow," he told CNN.

The ex-FDA head added that COVID-19 will likely circulate in high numbers in the winter and low numbers in the summer, comparable to the seasonal flu.

Under the Trump administration, Gottlieb served as FDA commissioner from 2017 to 2019. He presently serves on the boards of several firms, including vaccine maker Pfizer.