Following CDC Director Dr. Robert Redfield's warning that a second wave of the coronavirus in the winter could be worse than the current outbreak, the FDA commissioner said the whole White House Coronavirus Task Force is concerned about a resurgence of the disease. Dr. Stephen Hahn said on "CBS This Morning" Wednesday that because of that possibility, surveillance and testing will be "critical."

"Dr. Redfield's concern is that there also might be flu at the same time," Hahn said. "But that's why we have built into the plan the surveillance mechanisms to look for the respiratory illnesses and then do the appropriate testing at that time. That's going to be a critical part of the reopening plan to allow us to move forward."

The United States is currently doing fewer than 200,000 new coronavirus tests per day, according to the COVID Tracking Project, but experts have said that number needs to at least double or triple for social distancing measures to be lifted safely.

On testing, Hahn said "there is unlocked capacity in the country."

"We're working very closely with the governors and the state public health officials to make sure that the adequate supplies and the information about where those tests are available are made known to folks so that they can actually unlock that capacity," he said.

Hahn said he believes doubling the country's testing "could be done this week if the appropriate identification occurs at the state level and then the supplies are there for them."

The FDA has issued 59 Emergency Use Authorizations for tests, Hahn said. Four are for antibody tests, and the rest are for diagnostic tests.

It also authorized the first at-home diagnostic test that will be made available to health care workers and first responders. If they have symptoms, they can fill out an online questionnaire and if they meet the CDC guidelines, they will be sent the nasal swab kit developed by LabCorp.

"It's very easy and safe to perform," Hahn said. "Our data show that it's as accurate as having it performed in the doctor's office or in a clinic."