MANCHESTER — A recording of a meeting in August of local, state and federal health officials shows that the Vermont Department of Health was not willing to accept the positive antigen test results even after being told by federal officials they found no issues with the tests and that there was an accuracy issue with the state’s PCR test.
The conference call, held Aug. 18, included close to a dozen people from the Vermont Department of Health, Centers for Disease Control and Prevention and the United States Food and Drug Administration, as well as representatives from test producer Quidel and Manchester Medical Center.
During the call, Vermont Public Health Commissioner Dr. Mark Levine and State Epidemiologist Patsy Kelso were told by Brittany Goldberg, a senior medical officer in the FDA’s Division of Microbiology Devices, that their investigation found nothing wrong with the antigen testing device, materials or procedure used at Manchester Medical Center when 65 positive tests were detected in early July.
Goldberg also told them there was a known issue with the PCR testing software at that time and there were concerns about the amount of time that had passed between the antigen test and the PCR tests were conducted.
Levine has defended the accuracy of the PCR tests, which did not confirm the antigen test results, and in spite of the FDA’s position, does not accept the antigen results as “confirmatory positives.” He said they are to be considered “discordant results.”
Software IssuesThe PCR, or polymerase chain reaction, test used by the state is widely considered to be the best test available for accurately diagnosing a positive COVID-19 infection. But the test, like others, has shortcomings and isn’t right all the time.
Research published by Harvard Medical School puts the PCR’s false negatives — tests in which the patient is sick but results come back negative — at ranging from 2 percent to 37 percent.
Some of the most important factors include the amount of time that has passed since the person was infected with the virus.
There is also the time from when a sample is taken and it is tested.
But the test has also had a couple of issues and one of those was a software issue that had become known to affect the accuracy of some PCR tests.
“There has been a problem with interpretive software … and we have seen some false positive results, but there is also the potential for negative,” Goldberg told the group at the August meeting. “So my understanding is that the labs are going to be asked to update their software and re-review the previous results, to ensure that they were getting accurate results from that assay.”
Goldberg said the antigen test had been performed as it should and there were issues with the PCR testing software, but there were also concerns about the amount of time that had elapsed between the antigen positive results and when those samples could be tested using the PCR test for confirmation.
“If you don’t have a good solid high sensitivity PCR done within a reasonable timeframe, it becomes really difficult to determine what is the clinical truth of that sample,” Goldberg said. “It was really difficult to get a good timeframe between when the antigens were done and when the PCR was done, and if they’re not done very quickly, you know in a good timeframe together, you know you can’t really get the truth of that sample and so it’s hard for me. In the absence of having a really firm indication that something is wrong [with the testing procedure], you know, it’s a plausible clinical scenario.”
In July, Manchester Medical Center, through the town of Manchester, announced that dozens of people had tested positive for COVID-19 with a rapid antigen test.
The situation was perfect. Manchester had just been packed with tourists for the Fourth of July holiday, sports tournaments had kids packed together with sleepovers, and friends and families had gathered in large groups for the holiday.
Almost nobody was surprised as the number ratcheted up daily, eventually reaching 65 positive cases.
Several towns all but shut down. Offices closed, businesses shut down, restaurants went back to curbside only service and people went home and stayed there.
More than 1,600 PCR tests were performed in Manchester and Londonderry and results came back overwhelmingly negative.
Manchester Medical Center’s staff stood by their results, explaining that the positive test results didn’t come in a vacuum.
Dr. Janel Kittredge-Sterling, an emergency physician who co-founded Manchester Medical Center with her husband and fellow emergency physician, Dr. Thomas Sterling, said that most of the patients tested were either exhibiting symptoms of COVID-19 or had been in close proximity to someone who had tested positive.
An investigation was launched as the Centers for Centers for Disease Control and Prevention and United States Food and Drug Administration along with Quidel, the manufacturer of the test, launched an investigation.
When, in August, Quidel announced the findings that there were no issues with the test, the material used in the test or the procedures, the company pointed fingers at the PCR test questioning those results.
Levine, during one of Gov. Phil Scott’s twice-weekly news conferences, said the statements were “inappropriate” and not backed by science.
Should be accepted’
Goldberg also told Manchester Medical Center and the Department of Health that she believed the positive antigen tests should be accepted as positive cases. And, she said that considering them positive was the right thing to do.
“In general, I would say that, given the risk of spread, positive antigen results, should be considered a true positive,” Goldberg said. “I typically err on the side of caution.”
She also said that, given all the factors, she couldn’t rule out that the positive antigen tests, despite the negative PCR results, weren’t true positives.
After having been under the microscope for a month at the time this meeting took place and being the subject of intense debates in social media MMC found the FDA’s backup freeing.
John Mallard, the executive director of Manchester Medical Center, told the group on the call that MMC was planning to reach out to all of its patients who had tested positive and inform them that they were, in fact, true positives
“For us, one of the things that we really kind of hope to close this up with — both our town of Manchester and our patients — is that they were informed that their positives were false positives,” Mallard said. “We intend to reach out to all of our patients and let them know that you know, this investigation is over, and they were positive.”
The Health Department wasn’t ready to accept that.
Epidemiologist Kelso encouraged Levine to weigh in.
“I wonder, Dr. Levine, if you want to weigh in,” Kelso asked. “So that Manchester Medical Center is clear, I do not believe that the Health Department will consider these positives, so that might create additional confusion if you send that message out.”
Levine backed up Kelso.
“Technically speaking these will not have been confirmatory positives,” Levine said. “ I guess they will remain discordant results.”
And, the department only counted the handful of cases that ended up with a positive PCR confirmation of the antigen results as part of Vermont’s official results.
But Mallard said the FDA is considering them to be positive results, “which means the antigen was positive.”
“They were told they were false positives,” Mallard said. “There is correction that needs to be made. So we could say that they weren’t confirmed by a PCR, which we’re totally comfortable with. But telling the patient, and informing them that they were false positives, that is not correct, and needs to be corrected.”
Why not accept the tests?
Goldberg asked the Department of Health representatives why they wouldn’t accept the cases as positives.
“So, what is the worry,” Goldberg asks. “It doesn’t seem in keeping with the CDC guidance. So what was the reason for them being considered false positives?”
Kelso said that many of the patients did have a PCR collected within two days and “those PCRs were negative.” She also pointed out the widespread testing in the community by the Health Department and Southwestern Vermont Medical Center, held a weeklong drive-through testing option.
“So we did not think there was ongoing transition in the community,” Kelso said.
When asked if Kelso was aware of the safety communications about the software issue in the PCR testing platform and Kelso confirmed she did.
“I think that is the one that our lab is using although I think they have a couple of different platforms so I’m not sure this is the one they were using,” Kelso said.
Dr. Janel Kittredge-Sterling said people continue to ask her about the situation and what happened with the FDA investigation.
“The fact that people are still asking, it means they never had closure to that situation,” Kittredge-Sterling said. “I want the public to know the results.”
She also said that as the local area, and the nation head into a time when infection rates are as high as they’ve ever been, it’s important that people be able to trust the tests they’re given, trust the Department of Health and their local medical clinics.
“We as a community and the United States need to accept every resource we have available to us right now,” she said. “We only have what we have and we have to be able to trust whatever we have.”