WASHINGTON, June 23 (CGTN) - COVID-19 has "brought this nation to its knees," Dr. Robert Redfield, director of the U.S. Centers for Disease Control and Prevention (CDC), said on Tuesday, testifying in front of a House committee along with Dr. Anthony Fauci, the government's top infectious disease expert.

The "one little virus" is probably going to cost the country seven trillion U.S. dollars, and the next few weeks will be critical to tamping down coronavirus hotspots around the country.

On the bright side, a COVID-19 vaccine could be available later this year or early in 2021, said Dr. Fauci.

Fauci and other top health officials also said they have not been asked to slow down testing for coronavirus, a controversial issue after President Donald Trump said last weekend he had asked them to do just that because it was uncovering too many infections.

"We will be doing more testing," Fauci told the House committee.

Since Fauci's last appearance at a high-profile hearing more than a month ago, the United States is emerging from weeks of stay-at-home orders and business shutdowns.

Dr. Richard Besser, former acting director of the U.S. CDC warned during the testimony that no state has effectively transitioned from stay-at-home orders "to a public health model of testing, tracking, isolating and quarantining."

However, the governors of Arizona, Florida and Texas have been bullish on reopening its economy, which has seen worrisome increase in the cases.

According to the data from the COVID Tracking Project, 25 U.S. states reported more new cases last week than the previous week, including 10 states that saw weekly new infections rise more than 50 percent, and 12 states that posted new records.

Texas reported one of the largest rises in new cases at 24,000 for the week ending on June 21, an increase of 84 percent from the previous week.

New cases in Florida rose 87 percent last week to almost 22,000, with the state's positive test rate nearly doubling to 11 percent.

Arizona reported 17,000 new cases, a 90-percent increase, with 20 percent of tests coming back positive, according to the analysis.

The governors of all three states have attributed the increases in new cases to more testing, echoes the President Trump's explanation. But the health experts said, "This is not an artifact of just more testing at all."

"In many states, the testing is increasing, but the percentage of those people who are positive is actually going much higher," said Michael Osterholm, director of the Center for Infectious Disease Research & Policy at the University of Minnesota.

Even with the increased testing, the country is still "way behind the virus," former U.S. Health and Human Services Secretary Kathleen Sebelius said. "We are still reacting. We're not ahead of it."

If the U.S. doesn't get control of the coronavirus pandemic by fall, "you're essentially chasing after a forest fire," Dr. Anthony Fauci told the House committee.