WASHINGTON (NEXSTAR) — As coronavirus infections rise in the United States after nearly three months of declines, public health officials say Americans must remain vigilant and careful even amid the vaccine rollout.

Top health officials including White House chief medical advisor Dr. Anthony Fauci and U.S. Centers for Disease Control and Prevention Director Rochelle Walensky warned that the new spike in infections — particularly in the northeast and states like Michigan — could wipe out vaccination successes.

“I remain deeply concerned about this trajectory,” Walensky told CBS’ “Face the Nation” Sunday. “Please, take this moment very seriously.”

Fauci said that while the spread of more transmissible variants is part of the problem, the spike cannot be attributed to that alone. He blamed spring breakers and the premature easing of COVID-19 restrictions.

He said the country is still seeing an average of 50,000 new cases each day.

“It went up to 60,000 the other day and that’s really a risk,” Fauci told “Face the Nation.” “That’s exactly what happened in Europe. … We don’t want to see that.”

The increase comes despite the fact that nearly 1 in 5 adults in the country are vaccinated. In Michigan, it’s nearly 1 in 3 and the state is still seeing a surge.

Fauci urged people not to travel and to abide by CDC guidelines to ensure a return to normalcy by the summer.

President Joe Biden said Sunday that he’s concerned, too.

“Apparently, people are letting their guard down,” he said.

He planned to meet with his public health team Monday to learn more about the uptick and was expected to make public remarks later in the day about the pandemic.

His administration is putting vaccine distribution into high gear, promising 200 million shots will have been administered before his 100th day in office next month.