Does contact tracing work, key to the COVID-19 fight?

In the battle against the COVID-19 pandemic, tracing contacts (notifying family, friends, coworkers, and others exposed to the newly infected) is key to cornering outbreaks and limiting spread as they reoccur. open counties.

But while health officials report some success in increasing the ranks of contact detectives, there are indications that many infected people and those they have been exposed to 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 have never been interviewed about their contacts or notified of possible exposure.

“It is clear that contact tracing is not reaching people,” said Dr. Rajiv Bhatia, an assistant clinical professor of population health and primary care at Stanford University. Two of his patients, he said, reported being exposed by a relative or coworker who had tested positive, and said they were never contacted by public health.

In Oakland, Dr. Noha Aboelata, executive director of Roots Community Health, cited recent examples as a patient who tested positive on June 12 and had not heard from public health in at least a week, and another with whom He spoke Thursday without being contacted in 15 days. She and other doctors and community leaders wrote to Alameda County supervisors and health officials demanding more information about the contact search effort.

“There is no doubt that the need for county contact tracking currently exceeds its ability to provide such tracking,” his letter said.

Contact trackers are not expected to reach every person potentially exposed by people who test positive for the virus. But it is impossible to know whether the two largest counties in the Bay Area have been successful because their health officials, who have kept a lot of information on the virus, refuse to reveal how many people they reach and how quickly.

Officials in both counties insist that their contact trackers make calls to patients in most cases within 24 to 48 hours, but acknowledged that they do not always contact them or their contacts.

“Once we know someone is positive, we have been able to make an effort to contact him 100% of the time within 48 hours,” said Santa Clara County spokesman David Campos. He said they reach the majority, but did not provide precise numbers or say how often the tracers make subsequent attempts.

In a meeting this week, Cindy Chávez, chair of the county board of supervisors, suggested that follow-up contacts could be more successful if case investigators worked at night or even 24 hours instead of 9-5, especially since time is critical with COVID-19.

Alameda County spokeswoman Neetu Balram said investigators follow up “with most cases reported within a day or two of the report.” Sometimes there are delays in obtaining patient information, and sometimes the person’s contact information is missing or inaccurate, she said.

“These delays can occur with any reportable disease,” said Balram. “But the large number of COVID-19 cases and the large number of tests conducted through new clinical laboratories and testing providers increase the likelihood of such delays.”

With highly contagious diseases such as measles or COVID-19, spread through sneezing, coughing, or close conversation, the infected person may not remember everyone who may have exposed, much less know how to communicate with them.

Still, Perry N. Halkitis, dean of the Rutgers School of Public Health, which advises New Jersey on its contact tracking program, said “contact tracking works if done right.”

“It is perfect? No, ”said Halkitis. “Is it the best solution we have now in the absence of a vaccine? Yes.”

Because the new coronavirus is transmitted so easily, health officials would ideally interview the infected person and three out of four of the person’s exposed contacts within 24 hours of notification of the case, Halkitis said. Stretching that to 48 hours “wouldn’t be great,” he said, and after three days “you’re starting to get too far away.”

Recent publicly available details of New York City hospitals and health centers illustrate the challenges of contact tracing in the Big Apple, one of the most affected cities in the United States. Of 7,584 COVID-19 cases reported from June 1 to 20, case investigators reached 82%, but only 37% provided at least one contact. The researchers reached 68% of the 6,672 identified contacts they gave them.

Few other health departments offer such detail. Oregon’s COVID-19 public data panel includes case-tracking information, reporting how many new cases met the 24-hour follow-up goal, which Stanford’s Bhatia said is the best report he has seen. It shows that the goal has been met most days since May 1.

The San Francisco control panel reports the percentage of new cases and their contacts reached by health officials, both currently 83%, below the city’s 90% target. But it doesn’t indicate how fast connections are made.

It is unclear to what extent staff is a problem. Dr. Mark Ghaly, Secretary of the California Health and Human Services Agency, said this week that the state is working toward its state goal of having 10,000 contact trackers by July. The state has set a goal for counties to have 15 tracers per 100,000 residents.