What to Know About Studies Using Antibody Tests


science / science 335 Views comments

What to Know About Studies Using Antibody TestsOn Monday, officials in Los Angeles County released preliminary results of a study that suggest roughly 4.1% of the county's adult population has already had the coronavirus, which translates to between 221,000 and 442,000 people, factoring in adjustments for statistical margin of error.That's a much higher number than confirmed case counts indicate. (As of early Tuesday, the county had 13,816 cases.)"We haven't known the true extent of COVID-19 infections in our community because we have only tested people with symptoms and the availability of tests has been limited," Neeraj Sood, a professor of public policy at the University of Southern California and lead investigator on the study, said in a statement.Dr. Barbara Ferrer, LA County's public health director, said in a statement that the early results pointed to the possibility that many people may have been unknowingly infected.The study relies on rapid antibody tests, which have faced concerns about accuracy.And as The Mercury News reported, a Stanford study that also showed higher rates of infection in Santa Clara County drew criticism, although that was largely from statisticians over the study's methodology.Still, experts have emphasized that more studies will help develop a clearer picture of the virus's true prevalence.In any case, officials say it's crucial to continue to adhere to public health orders for many reasons, including that if more people are infected but asymptomatic, they could unknowingly spread the virus.______A change to the USNS Mercy's assignmentOn Monday, my New York Times colleague John Ismay and I spoke with leaders aboard the Navy hospital ship Mercy. Here's our dispatch about how their assignment has changed:In the weeks since the Mercy arrived at the Port of Los Angeles from San Diego, the hospital ship's mission has been clear: Serve as a crucial relief valve for patients who have not been infected with the coronavirus as hospitals fill up with patients sick with COVID-19.In recent days, the work has shifted, but that underlying goal has remained the same, the commanding officer of the ship's medical facility told us."FEMA, after having made an assessment of the situation and the local needs, has changed our assignment," said Capt. John Rotruck, the medical treatment team's commanding officer.The Mercy has sent 40 medical staff members -- two family practice doctors, 16 nurses and 20 corpsmen, including two respiratory technicians -- to help care for patients who do not have COVID-19 at a state-run skilled nursing facility in Orange County."We're essentially augmenting their staff," Rotruck said, as the anticipated surge in COVID-19 hospitalizations has, for now, been held at bay.The capacity onboard will decrease to 250 beds from 1,000, in large part as a result of that staffing shift -- although officials emphasized that leaves more than enough space at the rate the Mercy has been taking in patients.At the same time, leaders aboard the Mercy said that most of the military crew is moving off the ship to stay at nearby hotels to make it possible for crew members to keep their distance from one another as they work, eat and sleep.Sailors will be bused from their hotels to work their shifts aboard the ship.The move, which will decrease the number of crew members staying aboard the ship to roughly 140 from more than 800, came as the number of crew members who may have been exposed inched upward.By Monday, Rotruck said that nine crew members had tested positive for the coronavirus and that about 130 people were in quarantine because they had come into what federal officials define as close contact with at least one of those nine. All of those in quarantine tested negative.All nine who have COVID-19 were outpatients as of Monday -- meaning their cases were not severe enough to warrant being hospitalized -- and their conditions are being closely monitored.Rotruck said that moving crew members off the Mercy was unusual but not unprecedented.During a previous mission, for instance, some medical staff members flew to Vietnam to provide medical care to patients on the Mercy, although they did not sleep on the ship.However, Rotruck added, "We have not done it to this scale," with the vast majority of the ship's crew members living ashore.A spokesman said Friday that the crew aboard the Navy hospital ship Comfort, which is docked in New York City, recently moved most of its crew to hotels ashore as well.Rotruck said that the Mercy was ready to care for coronavirus-negative seniors living in nursing homes, as the governor has previously announced, but none had been transferred yet.Such nursing home patients may be moved to the Mercy for care through the typical intake process, if, for example, a facility needed to free up space to care for COVID-19 patients.As of Monday evening, the ship had taken in 65 patients total since it docked in San Pedro, and its crew had performed 22 surgeries. There were 13 patients still being treated onboard, meaning that 52 had been discharged.This article originally appeared in The New York Times.(C) 2020 The New York Times Company