U.S. President Joe Biden said in a CBS interview on Sunday that it will be difficult for the United States to reach herd immunity against COVID-19 by the end of this summer.

So far, the United States has reported nearly 27 million COVID-19 cases, with a death toll of over 460,000. 

As of Sunday morning, the country had administered 41,210,937 doses of COVID-19 vaccines and distributed 59,307,800 doses, the Centers for Disease Control and Prevention said.