A second wave of the novel coronavirus will hit the US later this year with even more difficult ramifications than the current COVID-19 crisis that has claimed more than 45,000 lives and infected over 824,000 people in the country, a top American health official has warned.

Center for Disease Control and Prevention Director Robert Redfield told The Washington Post that the US will have the flu epidemic and the coronavirus epidemic at the same time.

If the first wave of the coronavirus outbreak and the flu season had peaked at the same time, it could have been "really, really difficult in terms of health capacity," he said.

Luckily, the arrival of the novel coronavirus in the United States came as the regular flu season was waning, he said.

"There's a possibility that the assault of the virus on our nation next winter will actually be even more difficult than the one we just went through," Redfield told the daily.

"We're going to have the flu epidemic and the coronavirus epidemic at the same time," he said, adding that having two simultaneous respiratory outbreaks would put unimaginable strain on the health-care system.

The White House emphasised on continuing with preventive measures to fight the coronavirus and increased testing.

"We were very clear in the guidelines that we believe we can monitor, again, monitor communities at the community level by using the influenza-like illness and the syndromic respiratory and gastrointestinal temp components of this particular virus,"  Dr Deborah Brix, member of the White House Task Force on Coronavirus told reporters when asked about the second wave.

"Obviously, when we have flu, and were working on an algorithm that you test for flu and then you test for COVID-19 and making sure that we are building the testing capacity to be able to do that because I think it's very important that you're going to be able - on the surface, a patient, when they come in with early flu and early COVID-19 can look very close to identical," she said.

There is need to have testing in place to be able to separate and ensure those patients receive the best treatment, Brix said.

"We are also hoping by that time we have additional treatment options for people with COVID-19 so that there will be additional treatment available in the fall," she said.

Responding to a question, Brix said that the situation could be pretty bad if the second wave of coronavirus hits the country in the winter.

"When you see what has happened in New York, that was very bad. I believe that we'll have early warning signals both from our surveillance that we been talking about in these on the vulnerable populations," she said.

"We're going to continue that surveillance from now all the way through the fall to be able to give us that early warning signal. I think what we've learned is how good Americans are about immediately reverting to all of those issues that they need to do in order to ensure that they are protected and their families," Brix said.