U.S. health officials answered questions from lawmakers about the response to the pandemic and what the plan is moving forward.
Dr. Anthony Fauci and his colleagues warned that the number of new cases has stopped declining.
"There still are challenges ahead, particularly with regard to the variants that have now become very familiar to us," said Fauci. "They are mutational changes in the virus strains that challenge us both from the standpoint of spreading more rapidly, having a greater degree of pathogenesis, and even evading some of our monoclonal antibodies."
There was also an exchange between Sen. Rand Paul and Dr. Fauci. The senator from Kentucky challenged Dr. Fauci about why Americans should keep wearing masks even after they're vaccinated.
Fauci argued that wearing a mask after getting vaccinated is important because of potential COVID variants.