Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases and White House coronavirus task force health advisor, warned Congress that if the United States reopens too quickly, only "needless suffering and death" will follow.

Testifying before the Senate Committee on Health, Education, Labor and Pensions on Tuesday, Fauci told lawmakers that the country is lacking in adequate testing and contact tracing infrastructure to safely monitor the spread of the virus as states begin to reopen.

"If we do not respond in an adequate way when the fall comes, given that it is without a doubt that there will be infections that will be in the community, then we run the risk of having a resurgence," Fauci told Senators over a virtual hearing. "I hope that by that time, in the fall, that we would have more than enough to respond adequately. But if we don't, there will be problems."

Fauci was not the only health expert that spoke before Senate on Tuesday, with the Food and Drug Administration Commissioner Dr. Stephen Hahn, Director of the Centers for Disease Control and Prevention Dr. Robert Redfield, and Department of Health And Human Services Admiral Brett Girior joining the Committee virtually.

The hearing focused on the importance of the country ramping up its testing measures in response the the continued spread of the virus, with Senator Lamar Alexander saying that while a future vaccine or treatment is going to be the "ultimate solution," to the coronavirus pandemic, "all roads back to work and school go through testing. The more tests we conduct, the better we can identify those who are sick and exposed."

Adding to the importance for broad testing and contact tracing, the University of Washington's Institutes for Health Metrics and Evaluations's a newly revised coronavirus mortality model predicts more than 147,000 American deaths by August, which is an increase by about 10,000 from its last projection. The researchers noted that the forecast reflects, "key drivers of viral transmission like changes in testing and mobility, as well as easing of distancing policies."

Total Global Cases: Over 4.3 Million

Total Deaths: Over 290,000

Total Recovered: Over 1.6 Million

Multiple Candidates

Moderna (MRNA  ) CEO Stephane Bancel stated during CNBC's Healthy Returns Virtual Summit on Tuesday that he hopes the United States and international regulators approve multiple coronavirus vaccines from several companies, due to the fact that no single manufacturer would be able to meet global demand.

"The odds that every program works are really low, obviously, but I really hope we have three, four, five vaccines, because no manufacturer can make enough dose for the plant," Bancel told the CNBC Summit.

Regeneron (REGN  ) CEO Leonard Schleifer, told CNBC that the problem that vaccines will face will not be with physical distribution by one manufacturer, but the ability to meet demand. There are more than 7.6 billion people in the world, which could take years to vaccinate.

"We simply cannot do this on an auction basis, whatever state and local area or company wants to pay the highest amount to get access, we cant do it that way," Schleifer stated. He added that it should be the role of government, both domestic and global, to ensure that a vaccine it distributed fairly.