HOW L.A. COUNTY BECAME CORONAVIRUS EPICENTER: Slower shutdown, density, poverty among theories.

Many epidemiologists pointed to densely packed neighborhoods with overcrowded housing, as well as high rates of poverty, homelessness and even pollution that could be fueling poor outcomes in L.A. County.

Another factor might be when local officials shut down. The Bay Area issued its stay-at-home order on March 16, followed by L.A. County three days later. Though earlier than the rest of the nation, the delay may have set the stage for L.A. County to succeed the Bay Area as California’s center for COVID-19.

Earlier: Coronavirus lessons on density, mass transit, bureaucracy and censorship: They kill.