Maine will begin this week to ramp up testing for COVID-19, with the state Center for Disease Control (CDC) prioritizing broader testing in congregant living settings, such as long-term care facilities and homeless shelters. But an internal discussion is being held over whether and how the state will engage in universal testing of workers in factories and patients in group homes before outbreaks are confirmed.
“We’ve had really extensive discussion around that, including with a very large and well respected organization here in the states, to think about how we might approach that,” said CDC head Dr. Nirav Shah at a May 11 press briefing.
This week the state announced that three group homes for Mainers with disabilities are experiencing outbreaks. Infections had previously been confirmed at six long-term care facilities.
Governor Janet Mills announced on May 7 that Westbrook-based IDEXX laboratories would provide the state with 5,000 tests per week “for the foreseeable future,” which will be added to the current CDC capacity of 2,000 per week.
State weighing universal testing in group homes
Shah said that while the state CDC was “not averse” to engaging in universal testing in all congregant care facilities, including group homes, they are still in the process of deciding what that policy might look like.
“There are a number of questions that are out there when we start thinking about that,” Shah said. “We’ve talked at meetings, for example, about how often should we re-test individuals? Should we test everyone in the facility? Or, for example, just start with the staff?”
“And then of course, the most difficult question of all: How should we think about positives?” he said, explaining that there would have to be a plan in place to ensure that all staff and patients who test positive could be isolated to prevent the virus from spreading.
“We’ve just got to think through all of the implications before we go down that pathway, not midway through,” said Shah.
The potential for false positives
Shah raised concerns about the positive predictive value (PPV) of the tests, or the likelihood a positive test result is a true positive rather than a false positive — an important consideration in widespread testing.
“For anyone who’s watching right now, take a second after this is over to look at the positive predictive value and you’ll see why this this can be concerning from a policy perspective, and why we have to think that through before we go down that route,” said Shah.
Alan Cobo-Lewis, a professor and head of the Center for Community Inclusion and Disability Studies at the University of Maine, agrees that false positives “could lead to unnecessary isolation and staff shortages,” but noted that “tests for current infections use RT-PCR, and those tests have generally had excellent sensitivity and specificity.”
“The only way they wouldn’t have good PPV would be if the prevalence of COVID infection were really low in this population—but the outbreaks that we’re now hearing about suggest that the prevalence can’t be all that low,” said Cobo-Lewis.
Cobo-Lewis suggested that the CDC should share its “best estimate of the PPV in this population for the tests they might use” and name the organization they’re working with to plan for broader testing in group homes.
“I would encourage Maine CDC, and the entire administration, to meaningfully involve the disability community in policymaking,” he said. “While the administration has had listening sessions and informational sessions, they haven’t always been as receptive as they could be in involving people in policymaking who are so directly affected by these decisions. We have a stake in this. We want to help. Let us in.”
Maine still below testing threshold for safe reopening
Even the increased number of available tests in Maine still falls short of the threshold national health policy experts say are needed to adequately detect outbreaks.
A May 4 report from the Center for American Progress estimates that Maine will need 2,400 tests administered each day to achieve a positive COVID-19 rate of two percent, which was the rate achieved by South Korea, the only large country that has successfully controlled coronavirus transmission without a lockdown.
“According to epidemiologists, a low positive rate is an indication that testing is widespread enough to catch nearly all of the infections in the population,” wrote report authors Topher Spiro and Emily Gee. “In comparison, as of mid-April, the United States had a positive rate of 18.7 percent.”
In addition to the testing threshold, the report identified two other requirements that states should meet in order to relax stay-at-home orders: low incidence of transmission, a requirement that Maine has met, and a high percentage of contacts that can be traced in order to track the spread of the disease.
Photo: Kena Betancur, Getty Images
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