Brooks acknowledged the "warning signal" seen in the agency's from the Northeast, which samples sewage in hundreds of sites searching for early signs of a surge.
The cases were reported from about 22 states, including Arizona, California, Texas and Washington.
However, a CDC spokesperson said that the agency remains confident that there have been enough positive lab tests "available for sequencing purposes" and that the agency's "Nowcast" estimates account for "changes in testing by design.
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