California Gov. Gavin Newsom calls the discovery of coronavirus-related deaths in the U.S. earlier than previously known “important forensic information.’’

They both died in their homes in February, several days before COVID-19 was known to have killed anyone in the U.S. No one knew it was coronavirus that killed them - until now.


Public health officials in Santa Clara County, California, on Wednesday provided more details about two residents who died because of COVID-19, one a 57-year-old woman who perished at home Feb. 6, the other one a 69-year-old man killed by the disease Feb. 17.


The cause of death in both instances was discovered through autopsies and confirmed by the Centers for Disease Control and Prevention. The fatalities were recorded several days before two deaths reported in Washington state Feb. 26, believed to be the first ones in the nation due to the coronavirus.


Because neither of the Santa Clara individuals had a recent history of travel or contact with COVID-19 patients, the new discovery indicates the virus was likely circulating in the U.S. earlier than previously thought, at least by early January.


California Gov. Gavin Newsom calls the discovery of coronavirus-related deaths in the U.S. earlier than previously known “important forensic information.’’


As such, the revelation will doubtlessly inspire much study and debate, but some epidemiology experts say it won’t have a major impact on the response to the virus.


Newsom said he has directed other counties to “go back as far as December to request coroners’ autopsy, to dig even deeper. … to ultimately help guide a deeper understanding of when this pandemic really started to impact Californians directly.’’


Scientists have suspected for some time that the coronavirus emerged in China before the often-reported timeframe of sometime in December. Dr. John Swartzberg, clinical professor emeritus at UC Berkeley and an expert on infectious diseases, said new data that has yet to be confirmed points to October or even September.


Health care personnel test a person in the passenger seat of a car for coronavirus at a Kaiser Permanente medical center parking lot in San Francisco.


With the large amount of travel between West Coast cities and destinations in China before the disease grew into a pandemic, Swartzberg said it’s not surprising cases of the new virus would soon develop stateside and go unnoticed.


“This occurred right in the middle of our influenza season in the West Coast,’’ Swartzberg said. “Since disease from SARS-CoV-2 presents like influenza in many cases, you can see how it would be confused between the two, and it would have been ignored since nobody even thought of it then.’’


Swartzberg is among the analysts who considers the new information about the likely origins of the coronavirus in this country more interesting than useful in fighting its harmful effects.


Swartzberg does not believe a quick end to the shutdown is in the cards. For one, he said it’s not clear yet that serological tests measuring antibodies on those who have been infected with coronavirus are accurate, and how long any protection would last. He also doesn’t see the numbers adding up favorably.


“Let’s assume 5% of the population has been infected and let’s assume they’re immune,’’ Swartzberg said. “It tells us 95% of the population is still susceptible to this virus, and that tells us that it’s going to be around a long time.’’


Dr. Neil Schachter, medical director of the Respiratory Care Department at Mount Sinai Medical Center in New York City, compares the findings to learning about how people came to America before Columbus arrived.


It’s enlightening, but does not set a path forward.


“Somebody has to write the history of what happened, and there may be implications in terms of where the disease originated and how it was transmitted to this country, and that may be very important for various other reasons,’’ Schachter said. “But I think from the public health point of view, the direction that we’re going in now is what’s going to be most important.’’


The steps in that direction, Schachter said, should focus on determining the virus’ prevalence in the general population, especially the rate of asymptomatic carriers, and learning how much immunity is developed by those who get infected, which remains unknown.


Recent studies by Stanford and the University of Southern California, both using antibody testing, showed there were 28 to 80 times more cases in the counties they analyzed – Santa Clara and Los Angeles, respectively – than confirmed cases.


The studies’ methodology has been heavily criticized by scientists, and the results stand in contrast to California’s relative success battling the virus compared to other large states. As of Wednesday afternoon, the country’s most populous state had recorded 37,344 cases – fourth in the nation – and 1,421 deaths, ninth highest.


California’s curve has generally moved in the right direction but has yet to flatten, and Newsom said Wednesday he’s not ready to lift the state’s shutdown.


Dr. Jeffrey Goad, who chairs the Department of Pharmacy Practice at Chapman University and has studied epidemiology, said some public health officials consider the earlier and likely wider spread of infection a sign that herd immunity may be closer to developing. According to that optimistic thinking, shelter-in-place mandates may be lifted safely fairly soon.


However, Goad says the new information suggesting an earlier start to the U.S. outbreak only accomplishes so much.


“It helps to fill in the picture of how the coronavirus started here in the United States, and maybe helps inform the models of where we’re going, but it really is a look back,’’ he said.