Bolstered by improved testing capacity and scientific research, members of a new Santa Clara County COVID-19 testing task force rolled out plans on Thursday to start testing more widely for the coronavirus.

Dr. Marty Fenstersheib, head of the new task force, told the Board of Supervisors' Health and Hospital Committee that he is confident the county will reach its stated goal of achieving 4,000 tests per day by May 31, the date when the public health officer's stay-at-home order is set to expire. New testing guidance also will focus on the county's hardest-hit areas and demographics, including parts of Mountain View, east San Jose and the south county.

Fenstersheib said that although testing has been slow — roughly about 1,200 done per day — the task force and county staff are gearing up a communications campaign to get people to come to testing sites. They'll also focus on targeted testing of thousands of people in "congregate settings" such as skilled-nursing and senior-care facilities.

The Health and Hospital Committee launched the special testing query on Thursday to gain a greater grasp on the county's progress in overall testing and trace-contact investigations. The latter follows the contacts of those who have tested positive for the virus so they can be tested and quarantined if necessary. The steps are necessary components to reducing the virus's spread and are key to reopening parts of the county's economy, Public Health Officer Sara Cody has said.

Fenstersheib reinforced that to control the virus, it's necessary to first stamp out the hot spots.

"Testing is not helpful unless you test those highest at risk for exposure," he said.

Fenstersheib, who was recently hired, said the task force has made good strides in forming a broader testing strategy since launching on Monday. The new testing guidance focuses on the most vulnerable populations in greater numbers and for the first time, identifies how many times a particular demographic should be tested for the coronavirus.

The new guidance doesn't change for people who have symptoms, who are already being tested. They are also retested in accordance with their clinical evaluation. There are multiple guidelines for testing people who are asymptomatic and test positive, however. Those people should be attested twice.

In jails, incarcerated individuals would also be tested twice — at their booking and after two weeks of quarantine, prior to being released into the jail population. That protocol has already been in effect, Sheriff Laurie Smith previously told the supervisors.

The new recommendations would test jail staff once every three weeks with 20% of the employees being tested at one time on a rotating basis.

In skilled-nursing facilities where there is no outbreak, asymptomatic patients would be tested once every five weeks. Staff would be tested once every two weeks, with 50% being tested on a rotating basis. Residents of shelters and other congregate-living settings would also be tested once every five weeks.

Asymptomatic health care workers and first responders would be tested once a month on a rotating basis of 25% of staff; asymptomatic front-line workers would be tested once per month at a minimum with testing repeated no more than one time in 14 days.

These tests would provide some monitoring and control measures, but it is only a beginning. The county needs to test 13,000 to 15,000 people per day to capture all of the people considered at-risk, said Ky Le, director of the county office of supportive housing, who is part of the new testing team.

How to get to that number — and even to the minimum 4,000 goal — concerned committee Chairman Joe Simitian. With two-and-a-half weeks left before the end of May deadline, he wasn't confident staff could reach its goal, he said.

County Executive Jeff Smith has said the capacity to do the 4,000 tests per day is there, but some of the public testing sites, including the Verily site at the Santa Clara County Fairgrounds and San Jose PAL Stadium, have not been well used by the public. At the board's full meeting on May 12, Simitian wanted a fuller accounting of how staff will communicate with the public to get more people to be tested. He reiterated that worry on Thursday.

"I'm concerned if we have the capacity, but we are not getting to the right folks," he said. It's important for the county to keep underscoring in a clear and concise manner that tests are available and how they can be obtained, he said.

Fenstersheib said he thinks increased communication will let the county reach its goals. "Messaging will drive demand," Fenstersheib said, noting the county has sent out 8,000 flyers so far notifying the public about the free testing.

Simitian underscored the difference between public health's epidemiological goals, as outlined in the county's new testing guidance, and the push to get regular folks out to the sites. When pressed, Fenstersheib said he thinks no one would be turned away if they show up for a test. The tests are not limited to the people on the guidance list, he said.

"I don't see the general public on the list. We need to be clear on that," Simitian said.

Supervisor Susan Ellenberg said it is important to make the tests available where people are located. People in skilled-nursing facilities should not be expected to go to a testing site, she said. Le said the team will go out to skilled-nursing facilities to do testing.

Just getting the test-kit components has been like a continuous game of Whack-A-Mole. There have been shortages of reagent, transport medium and test-kit swabs, which cannot be made of cotton because the DNA in the cotton would interfere with the genetic material labs look for to identify the coronavirus. Although the materials crisis has abated somewhat, there are still issues. As long as shortages are a factor, consistent testing will be a challenge.

Le said that while they have more than sufficient laboratory capacity to meet the county's initial goals, how long they can sustain the 4,000 tests per day is another question. Once again, that's based on materials.

During the meeting's discussion by infectious disease experts, Dr. Yvonne Maldonado, Stanford professor of pediatric infectious diseases and health research and policy, also said the lack of testing preparation is due in large part to the federal government.

"The federal system has failed us. I worked in the (U.S. Centers of Disease Control and Prevention) when HIV emerged," she said, when agencies could get the tests they needed.

"The supply chain is critical. You can't do a test without the supplies," Maldonado, who works with the CDC through the National Committee of the American Academy of Pediatrics.

The current federal government has not provided the infrastructure that other countries with successful testing regimens have: Taiwan, Hong Kong, to some extent China, South Korea and Singapore. Those countries had an infrastructure in place because of previous outbreaks related to other coronaviruses such as Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS). The U.S. also was prepared to respond to those diseases, she said.

Maldonado said there was not much communication from the CDC, so Stanford developed its own highly accurate swab test. So far, Stanford Health Care has done 50,000 tests and hopes to ramp up more testing. There are many different types of tests on the market that don't have commensurable efficacy, she said.

Maldonado said testing is paramount to controlling the disease.

"The most important thing (polymerase chain reaction ) PCR tests would tell us is how much infection we have now and to know how it is going to spread going forward," she said.

While PCR tests look at whether the disease is active, serological or blood tests look at antibodies and indicate who has had the disease. While antibody tests are getting much attention as a means for deciding who might have immunity — and thus might be an indicator of when the county can open up — relying on serological tests alone might not tell the whole picture.

"People don't have evidence of immunity in the first two weeks of the disease, but by four weeks most have antibodies," she said. "Some people on ventilators and in the ICU don't have antibodies (at all)." she said.

The medical community also doesn't understand what the antibodies mean: whether they just show that a person was exposed to the virus or if they can get an infection again.

There are also different kinds of antibodies that do different things. Testing is making progress on an important front in that regard. In the next few weeks, researchers will be able to detect neutralizing antibodies — at least in the test tube — for the SARS-CoV-2 coronavirus, the pathogen that causes COVID-19 disease, which could kill the virus, Maldonado said. Theoretically, these antibodies could prevent people from getting COVID-19 again, but researchers must test the antibodies in people to see what it does.

Progress is also being made on a variety of equipment fronts. Santa Clara Valley Medical Center has purchased a large testing machine that could be up and running by May 25, Smith said.

Stanford has purchased large machines that can potentially do hundreds of thousands of tests per day. The medical center is looking to automate some of the equipment so the work doesn't have to be done by hand, according to Maldonado.

All of that progress can stop in its tracks if the testing-materials supply lags. To get the materials they need on a consistent basis, counties and the state must continue to work with companies to do manufacturing.

Christina Kong, professor of pathology at Stanford University Medical Center and a member of the Gov. Gavin Newsom's COVID-19 task force said they are working with Redwood City-based Carbon to validate and manufacture 3-D-printed swabs. The new would be comparable to the specialized swabs currently used for taking nasopharyngeal samples.

Stanford is also using buffered saline as a substitute for the traditional transport media into which samples are placed to take to the laboratory. The medical center has had good success with buffered saline, although a University of California San Francisco study found the samples don't do well if they must travel long distances. Kong said that's not been a problem for Stanford, which can expedite their shipment.

Charlie Kim, head of molecular systems at Verily Life Sciences, set up the Verily testing site at the Santa Clara County Fairgrounds. While the site has helped to develop some general ideas of where the virus is in the community based on who is coming into the clinics, it's not enough. As counties start to reopen, he is concerned that health experts still don't have a good handle on where the virus is in the population.

We don't know what kind of transmission rates workers and owners of small businesses and restaurants are passing to their customers and their exposure from patrons to themselves, he said.

"There's a little bit of a disconnect between that information and the policies being made," he said.

Related content:

• COVID-19 testing expands in Santa Clara, San Mateo counties

Find comprehensive coverage on the Midpeninsula's response to the new coronavirus by Palo Alto Online, the Mountain View Voice and the Almanac here.