How to find hidden infections
Stanford and UC fast-track new tests
The majority of people with coronavirus feel just a little sick — and, untested, inadvertently infect others and spread the potentially deadly disease.
But this hidden population could soon be revealed by new tests available on-site at Stanford and UC San Francisco. Striving to meet the growing demand for rapid answers. Stanford deployed its test on Wednesday. UCSF’s test, which could deliver results even faster, will soon follow.
“This will give us an enhanced capability to test a wider swath of individuals,” said UCSF’s Dr. Charles Chiu. “We really have to answer whether or not there is ongoing community transmission.”
On Tuesday, Santa Clara County health officials announced two additional coronavirus cases in which the source of infection is unclear. The latest announcement brings to 11 the total number of cases in the county.
Worried by the specter of community spread, the county issued new recommendations for people at risk of the disease. It urges residents over age 50 or those with medical conditions to avoid large public gatherings. such as movie screenings, bingo games, parades, sporting events and concerts where large numbers of people are within arm’s length of one another. It does not include typical office environments, grocery stores, or shopping centers, where it is unusual for large numbers of people to be within arm’s length of one another.
A Berkeley resident also has tested positive, according to city officials there. This person has largely remained at home in a selfimposed quarantine since their return from overseas travel.
Contra Costa County confirmed its first positive case Tuesday in a patient who had no travel history or contact with a known sick person. According to Dan Peddycord, director of public health, and Ori Tzvieli, medical director for the public health division, the person is an adult male with underlying health conditions who was initially hospitalized with respiratory and flu-like symptoms. The man is in critical condition and isolated in an area hospital.
Globally, 90,870 cases have now been reported in 72 countries, with more than 3,000 deaths.
On Tuesday, the death toll in Washington state had risen to nine. And health authorities discovered that two people who died last week were infected — suggesting that the virus had spread in the region days earlier than they had known.
But those cases don’t reflect the true scope of the epidemic, experts said. Like an iceberg, many cases may not be seen, because people don’t seek medical help.
Research in China shows that about 82 percent of the cases are mild, and that proportion may be an undercount, due to inadequate testing. Young people, in particular, stay healthy, with only 2.4% needing medical intervention. Many are presumed to carry the virus, but they successfully fend off disease.
Health officials worry that younger people could unwittingly infect elders, who are at great risk.
Additionally, there is emerging evidence that some patients spread the virus during its incubation period, which may last 14 days, then realize they are sick.
Right now, only a narrow group of people are being tested: those who are very sick and hospitalized, have recently traveled to China or South Korea or have been in contact with someone confirmed to have the virus.
The federal Centers for Disease Control and Prevention has strict criteria for testing — and, until this week, the agency has been the only organization that was testing. The turnaround time for a result from the CDC has been up to 72 hours. And the rollout of the test was delayed due to technical problems.
As of Tuesday, 54 local and state public health labs, including Santa Clara and Alameda counties, were able to conduct tests, according to the Association of Public Health Labs. Each lab can test 100 patients per day. When fully online, 100 public health labs will be capable of testing 10,000 patients a day, it said. But the U.S. Food and Drug Administration provided a higher number, saying labs will be able to test up to 75,000 people.
“We’re testing everybody that we need to test,” President Donald Trump insisted on Wednesday during his first press conference on the coronavirus.
While the number is increasing, tests still aren’t widely available to the hospitals, clinics and public health labs across the country that need them, say doctors.
It’s essential to catch infections quickly — on site — so sick people can be isolated before they spread the virus to healthcare workers, other patients, family members and friends.
‘We could make a diagnosis at the front desk,” said Dr. Yvonne Maldonado, infectious disease specialist and director of Inspection Control at Stanford Children’s Health.
Then the patient could be quickly directed to a special isolation room, far from crowded waiting rooms, and treated by experts in protective gear.
Until last week, academic and commercial labs weren’t allowed to run the tests. But the FDA issued new rules late last week.
“That was a game changer,” said Chiu. “It permits local labs to do their own testing.”
The tests are possible because the full genome of the novel coronavirus was published on Jan. 10, just weeks after the disease was first identified in Wuhan, China
The Stanford test, designed by the lab of Dr. Benjamin Pinsky, medical director of the university’s Clinical Virology Laboratory, uses an approach called qualitative real-time, reverse transcriptase PCR. It detects the presence of the virus’s E gene, which codes for the envelope that surrounds the viral shell, as well as another gene.
Doctors take swabs from the back of the throat, above the soft palate that connects the nose to the mouth. Turnaround time for this test could be as fast as 6 hours. On Monday, it earned federal approval.
UC San Francisco and the San Francisco biotech company Mammoth Biosciences are taking a different approach. They enlist CRISPR, the famed geneediting tool, to detect snippets of the virus’s genetic material. They’re still working to validate the test’s accuracy and sensitivity, but aim to release it within several weeks.
In practice, the UCSF tool would work like a pregnancy test, with results in one to two hours. A strip of special paper would be dipped into a sample containing the CRISPR system. If the patient’s sample contains the virus’s genetic sequence, it would change color.
Harvard and several New York-based universities, as well as international groups in Europe and Hong Kong, also are working on their own versions of new tests.
“From a hospitals perspective, we would like to know — in everyone, where it’s plausible — whether or not COVID-19 is a possibility,” said Paul Biddinger, Director of the Emergency Preparedness Research, Evaluation and Practice Program at Harvard’s T. H. Chan School of Public Health.
“It all ties to testing,” he said.