New White House Covid projection puzzles experts and catches some Biden officials off guard

It was a stern and startling warning from the White House's new Covid response coordinator: In the fall and winter, the US could potentially see 100 million new Covid-19 infections if Congress doesn't approve federal funding to fight the pandemic.

That warning from Dr. Ashish Jha, who said the projection was based on a range of internal and external models, jolted some public health experts and even came a surprise to some top Biden administration officials, with sources telling CNN that the grim forecast -- and details of where exactly that 100 million number had been derived from -- was not discussed with some key officials intimately involved in the administration's work to fight Covid before Jha's TV interview over the weekend.

As of Thursday morning, the White House had not yet released the underlying data that it says supports its projection. A senior administration official had told CNN on Monday that the 100 million infection number is a moderate one that falls somewhere in the middle of more conservative and extreme projections and is based on an underlying assumption of no additional resources or extra mitigation measures being taken, including new Covid-19 funding from Congress, or dramatic new variants.