California's Santa Clara County announced on Tuesday that two people who died in their homes in February were later confirmed positive for the new coronavirus.

This data suggests the first US COVID-19 death occurred at least three weeks earlier than previously thought.

The US recorded its first official death from COVID-19 on February 28.

Santa Clara County said in a press release that the new COVID-19 cases were not detected sooner because the people "died at home during a time when very limited testing was available only through the CDC."

Visit Business Insider's homepage for more stories.

California's Santa Clara County on Tuesday announced that two people who died in their homes in February later tested positive for the new coronavirus, suggesting that the first COVID-19 death in the US occurred weeks earlier than previously thought.

In a statement Tuesday, officials from Santa Clara County said the medical examiner tested three people who died in their homes for coronavirus. One person died February 6, another February 17, and a third on March 6.

According to the statement, the tests were sent to the US Centers for Disease Control and Prevention, which confirmed on Tuesday that all three patients tested positive for coronavirus.

The US recorded its first official death from COVID-19 on February 28 — a man in his 50s in Washington state. The new data suggests the country's first death occurred at least three weeks prior.

California confirmed its first coronavirus death on March 4 — an elderly patient in Placer County, near Sacramento. Santa Clara County, which includes San Jose in the Bay Area, initially recorded its first death on March 9 — a woman in her 60s.

Santa Clara County said in a press release that the new COVID-19 cases were not detected sooner because the people "died at home during a time when very limited testing was available only through the CDC."

It said the CDC at the time had restricted COVID-19 testing to only people with a known travel history to affected areas or those who reported specific symptoms associated with the illness.

"As the Medical Examiner-Coroner continues to carefully investigate deaths throughout the county, we anticipate additional deaths from COVID-19 will be identified," the statement said.

The US has been criticized for its slow testing per capita compared with other countries. The delay was initially blamed on test-kit shortages and faulty kits.

The US Food and Drug Administration announced an expansion of its distribution of coronavirus testing kits on February 29, allowing hundreds of labs and hospitals around the country to conduct testing that had previously been limited by the CDC.

President Donald Trump said during a Monday briefing that the US had tested more than 4 million people for the coronavirus, completing 150,000 tests a day.

A comparison of testing per capita in six countries shows the US has finally caught up with other nations in its testing capacity, though it trailed behind other countries for weeks.