Over half of all Californians will be infected with the novel coronavirus in the coming months, California Gov. Gavin Newsom projected in a letter to President Donald Trump.

The March 18 letter asks Trump to deploy the USNS Mercy hospital ship to serve as a floating health care center until September.

"In the last 24 hours, we had 126 new COVID-19 cases, a 21 percent increase," Newsom wrote. "In some parts of our state, our case rate is doubling every four days. Moreover, we have community acquired transmission in 23 counties with an increase of 44 community acquired infections in 24 hours. We project that roughly 56 percent of our population — 25.5 million people — will be infected with the virus over an eight week period."

A spokesperson for Newsom later told Politico that the 56 percent number reflects the infection rate if "mitigation efforts aren't taken into account." Currently, most of the Bay Area and the city of Fresno are under shelter-in-place orders — the most stringent in the nation — but the remainder of the state is not.

Newsom's numbers echo many projections for coronavirus spread around the world. One Harvard epidemiologist told the Wall Street Journal he expects 40 to 70 percent of the global population will be infected this year; a biostatistician who consults for the World Health Organization projected two-thirds of all people will eventually contract COVID-19.

In anticipation of overcrowded hospitals, Newsom asked the USNS Mercy be allowed to dock in Los Angeles to "address critical acute care needs, such as heart attacks and strokes or vehicle accidents, in addition to the rapid rise in COVID-19 cases." Mercy is homeported in San Diego in reduced operating status.

California has nearly 1,000 confirmed cases of COVID-19 as of Thursday afternoon, according to a tracker from Johns Hopkins University & Medicine.

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