City of San Jose projections suggest a staggering 2,000 people in Santa Clara County could die of coronavirus by June, despite unprecedented measures shutting businesses and isolating people at home to check its rapid spread.

County public health officials, who have been leading the local coronavirus response, declined to endorse those estimates — far higher than other such numbers.

Put into perspective, the city estimates are more than 100 times the current 19 COVID-19 deaths and more than 300 times the six influenza fatalities among those under 65 counted so far in Santa Clara County. They are nearly double the current coronavirus death toll for the entire country. Because the disease spreads exponentially, it is believed that the numbers will grow dramatically; still the city estimate is extraordinary.

San Jose Deputy City Manager Kip Harkness, who delivered the projection during a City Council meeting on Tuesday, said then it came from the city’s office of emergency management, which looked at an array of outcomes based on levels of “social distancing” suppression of public interaction.

“Even in the best-case scenario, we were looking at the order — in the next 12 weeks — of 2,000 potential deaths directly from COVID-19,” Harkness said at the meeting, referring to the “full suppression” shelter-in-place measures that county health officers around the Bay Area imposed March 16.

With more modest measures or lack of compliance, fatalities could triple to 6,000, Harkness said, and without any social distancing the number could reach as high as 16,000.

Harkness told the council the data is a “rough estimate,” clarifying that Santa Clara County was working on a “much more detailed and robust estimate” itself. “But given the urgency of this situation, we have decided to share these preliminary results in order to drive the action needed to save lives,” he said.

Neither Harkness nor other officials in the city’s office of emergency management could be reached Thursday.

Santa Clara County public health officials stressed Thursday that they did not produce or review the city’s projections and said they are not prepared to make their own.

“The County of Santa Clara continues to actively assess the situation and take necessary actions to slow the spread of the novel coronavirus in our community and protect those most at risk for severe illness,” the county public health department said in a statement.

Despite the statement, County Executive Jeff Smith did appear to have reviewed the projection.

In an email to San Jose Mayor Sam Liccardo, city manager Dave Sykes and Harkness, Smith said called it a “worst-case scenario”, but added that it “was not wrong in any way.”

“…the projections it makes are based on national and international numbers not exclusively on county numbers. It would be best if you added that caveat to the discussion,” Smith said in the email.

San Jose Mayor Sam Liccardo, who defended the model, said that it was created by city staff using a COVID-19 planning tool created by Professor Richard Neher at the University of Basel in Switzerland.

“We don’t have epidemiologists on call but what we do have is people smart in math who are adopting models that have been published by other experts,” Liccardo said in an interview Thursday night. “Kip (Harkness) put together a model that assumed there would be mitigation and that used an R-naught that was lower than most.”

An R-naught refers to how many people are likely to get a virus from each infected person — serving essentially a measurement of contagion. The city used an R-naught of 2.2, which is lower than the figure that the state’s data chief is using — 2.4, Liccardo said.

“I don’t think that what Kip presented is alarmest, but I look forward to hearing from experts,” he said.

The city of Oakland and Alameda County’s public health departments did not respond to questions about whether they had made any such projections.

Harkness did not tell the council how city staff arrived at the estimates, which are higher than those from other agencies. Coronavirus has killed just over 1,000 people in the U.S. so far, including about 80 people in California.

As of Thursday, there are 3,955 confirmed cases of COVID-19 in California, according to the total cumulative cases as reported by the counties and compiled by the Bay Area News Group.

Santa Clara County, which reported the first Northern California infection Jan. 31, is the hardest hit in the Bay Area with its confirmed 542 positive tests, 154 hospitalizations and 19 deaths. Nearly half of the total cases are presumed to have come from community transmission.

But, as public health officials continue to remind people, that number grossly underestimates the total number of cases within the community.

Tests, as well as data from academic, commercial and pop-up labs, are still hard to come by, and many symptomatic or exposed individuals are being told simply to isolate at home.

On Tuesday, Alameda, Contra Costa, Marin, San Francisco, San Mateo and Santa Clara counties, along with the city of Berkeley, which has its own public health department, announced a new order that requires all labs to report test results for all residents to both the health care provider and county officials.

“If we have both the positives and negatives, then we can have the denominator of who’s being tested, where we have hotspots,” Santa Clara County Health Officer Sara Cody said Tuesday.

Approximately 77,800 tests have been conducted across California — the results of nearly 75 percent of which are still pending. When those results do come back, the state could potentially see the numbers of confirmed cases spike by four times what public health officials have recorded to this date.

The projections from San Jose’s Office of Emergency Management that were shared with the council suggest there are actually 9,000-19,000 cases of coronavirus in Santa Clara County today.

“So, that means we have a false sense of security in terms of thinking, ‘Oh, everyone who’s tested are the only ones who are infected,’ ” Harkness said. “There are a large number of us walking around who are infected.”

This story will be updated.