CDC: First US coronavirus deaths happened weeks before first death in Kirkland

The first known people to die in the U.S. from coronavirus were not in Washington after all.

Health officials in Santa Clara County, California, say they’ve determined two people died of COVID-19 on Feb. 6 and 17, earlier than the two people who died in Washington Feb. 26.

“What these deaths tell us is that we had community transmission probably to a significant degree far earlier than we had known,” said Dr. Sara Cody, health officer for Santa Clara County.

Dr. Ashish Jha, cirector of the Harvard Global Health Institute, told CNN, “If you think about it, somebody who died on Feb. 6, they probably contracted that virus in early-to-mid January.”

"What's interesting about these new cases is that they don't have a reported travel history," said Louise Moncla, a virologist at Fred Hutch in Seattle.

Moncla said it will be important to figure out if the early California cases were part of a small or large transmission chain.

"What's a little puzzling about this finding is that if there was widespread transmission in California for 20 days before we knew it in Washington, we would have expected there to be an outbreak, a large number of people going to hospitals and dying in California before we saw our outbreak in Washington," Moncla said.

Stephen Hawes, who chairs the University of Washington Department of Epidemiology, said new antibody tests will be important for understanding the scope of early infections.

"It won't tell you the timing of that, when the initial infection happened, but it will at least tell you if the person was exposed and infected by the coronavirus," Hawes said.

King County officials wrote to KIRO 7 that at the start of the outbreak, the King County Medical Examiner’s Office did not retrospectively test people who had died earlier in February because of limited testing.

Officials say they did not preserve samples for later testing, but will now test four bodies that are still in the office.

Officials say blood samples are kept from autopsies, but there are no current plans to use those samples to test for antibodies.

The Associated Press contributed to this report.