In the battle against the COVID-19 pandemic, contact tracing — notification of family, friends, co-workers and others exposed to the newly infected — is key to corralling outbreaks and limiting spread as counties reopen.
But while health officials report some success in beefing up the ranks of contact sleuths, there are indications that many infected people and those they may have exposed are falling through the cracks.
That has alarmed some doctors in the Bay Area’s two most populous counties, Santa Clara and Alameda, who cite recent examples of infected or exposed patients who were never interviewed about their contacts or notified of their potential exposure.
“It’s clear contact tracing is not getting to people,” said Dr. Rajiv Bhatia, a clinical assistant professor of primary care and population health at Stanford University. Two of his patients, he said, reported being exposed by a relative or co-worker who had tested positive, and said they never were contacted by public health.
In Oakland, Dr. Noha Aboelata, chief executive officer of Roots Community Health, cited among recent examples a patient who tested positive June 12 who hadn’t heard from public health in at least a week, and another she spoke with Thursday hadn’t been contacted in 15 days. She and other doctors and community leaders wrote Alameda County supervisors and health officials demanding more information about the contact tracing effort.
“There is no question that the county’s need for contact tracing currently outstrips its ability to provide such tracing,” their letter said.
It’s not expected that contact tracers will reach everyone potentially exposed by people who test positive for the virus. But it’s impossible to know whether the Bay Area’s two largest counties have been successful because their health officials — who have closely guarded much information about the virus — refuse to reveal how many people they do reach, and how quickly.
Officials with both counties insist their contact tracers make calls to patients in most cases within 24 to 48 hours but acknowledged they don’t always reach them or their contacts.
“Once we know someone is positive, we have been able to make an effort to contact them 100% of the time within 48 hours,” said Santa Clara County spokesman David Campos. He said they reach most, but did not provide precise numbers or say how often the tracers make subsequent attempts.
At a meeting this week, Cindy Chavez, president of the county board of supervisors, suggested contact tracing could be more successful if the case investigators were working evening hours or even around the clock rather than 9 to 5, especially given that time is critical with COVID-19.
Alameda County spokeswoman Neetu Balram said that investigators follow up “with most reported cases within a day or two of the report.” Sometimes there are delays in getting patient information, and sometimes the person’s contact information is missing or inaccurate, she said.
“These delays can happen with any reportable disease,” Balram said. “But the sheer numbers of COVID-19 cases and the large amount of testing done through new clinical labs and testing providers increase the likelihood of such delays.”
With highly contagious diseases like measles or COVID-19, spread through sneezes, coughs or close conversation, the infected person may not recall all those they might have exposed, let alone know how to reach them.
Even so, Perry N. Halkitis, dean of the Rutgers School of Public Health, who is advising New Jersey on its contact tracing program, said “contact tracing works if it’s done well.”
“Is it flawless? No,” Halkitis said. “Is it the best solution we have now in the absence of a vaccine? Yes.”
Because the new coronavirus is so easily transmitted, health officials ideally would interview the infected person and three out of four of the person’s exposed contacts within 24 hours of being notified of the case, Halkitis said. Stretching that out to 48 hours would be “not great,” he said, and after three days “you’re starting to get too far out.”
Recent publicly available details from New York City Health and Hospitals illustrate the challenges of contact tracing in the Big Apple, one of the worst-hit U.S. cities. Of 7,584 reported COVID-19 cases from June 1-20, case investigators reached 82%, but just 37% provided at least one contact. The investigators reached 68% of the 6,672 identified contacts they were given.
Few other health departments offer such detail. Oregon’s public COVID-19 data dashboard includes information on case follow-up, reporting how many new cases met the goal of follow-up within 24 hours, which Stanford’s Bhatia said is the best reporting he’s seen. It shows that goal has been met most days since May 1.
San Francisco’s dashboard reports the percentage of new cases and their contacts that health officials reach — both currently 83%, short of the city’s 90% goal. But it doesn’t indicate how quickly the connections are made.
It’s unclear to what extent staffing is an issue. California Health and Human Services Agency Secretary Dr. Mark Ghaly said this week the state is working toward its statewide goal of having 10,000 contact tracers by July. The state has set a goal for counties to have 15 tracers per 100,000 residents.
Santa Clara County has 501 case investigators and contact tracers, well over the 289 the state suggested, and plans to expand that force to nearly 1,000 by the end of July.
Alameda County has “nearly 100” case investigators and contact tracers, Balram said, less than half the 247 the state formula recommends.
Efforts to help notify the potentially exposed through cellphone apps that have worked well in Asia have proven more problematic in the U.S., where people are more protective of their privacy, Halkitis said. A Wall Street Journal report this week also found problems with many apps’ accuracy.
“At this point, the technology is still evolving,” Halkitis said. “I don’t think this is ready for prime time right now.”
