US Surgeon General Dr. Jerome Adams has warned the American people that "this virus is incredibly unforgiving," during an interview with Good Morning America on Monday.
"It's really concerning to me that we still have people out there who don't understand how much spread is occurring by people who don't have symptoms, who think they're fine, and then we find out a week later that they've tested positive and they've exposed other people," Adams said.
Adams noted that Covid-19 cases and hospitalizations are still going up.
"My colleagues are dog tired and we need you to hang on just a little bit longer because we've got vaccines coming, but we want as many people to be alive to get them as possible," he said. "A lot of that is going to depend on your behavior."
Adams added that despite his concerns, more people than ever are wearing masks in the US.
The US has the highest Covid-19 case tally globally, with more than 14.7 million total infections recorded.