Agency Says CDC Virus Tests Are Contaminated and Poorly Designed

Faulty coronavirus test kits developed by the Centers for Disease Control and Prevention in the early weeks of the epidemic were not only contaminated but also had a fundamental design flaw. an internal review by the agency.

Health officials had already acknowledged this. test kits are contaminated, but the internal report, whose findings were published Wednesday in PLOS ONE, also documented a design flaw that caused false positives.

The distribution of faulty test kits at a time when no other testing was authorized hampered efforts by health officials to detect and track the virus.

Stanford Health Care clinical virology director Dr. “It delayed the availability of more widespread testing,” said Benjamin Pinsky. “I think it’s important that they get to the root of what went wrong,” he added.

In January 2020, the CDC developed a polymerase chain reaction, or PCR, test for the virus. PCR tests done in laboratories can detect the virus at very low levels and are considered the gold standard for diagnosing a coronavirus infection.

Problems arose soon after the CDC began shipping test kits to public health labs in early February. Within a few days, many labs reported that the tests had yielded unsatisfactory results.

In mid-February, the agency acknowledged: kits were defectiveIn April, U.S. Food and Drug Administration officials said poor manufacturing practices were causing test kits to become contaminated.

The new paper presents the results of the CDC’s own internal research into testing-related issues.

The CDC’s test was designed to detect three different regions, or target sequences, of the virus’s genetic material. The assay kits contain an array known as primers that bind to and make copies of target sequences, and probes that produce a fluorescent signal when these copies are made, indicating that genetic material from the virus is present.

Primers and probes must be carefully designed to bind to target sequences and not to each other. In this case, this did not happen. One of the probes in the kit sometimes binds to one of the primers, producing a fluorescent signal and producing a false positive.

“This is something that needs to be caught in the design phase,” said Susan Butler-Wu, a clinical microbiologist at the University of Southern California Keck School of Medicine. “This is something you should check out.”

The investigation also confirmed that the test kits were contaminated with synthetic fragments of the virus’ genetic material. Frequently used to ensure that tests run properly, these synthetic sequences were produced in the CDC lab where test kits undergo quality analysis. The agency concluded it was “likely” that the test kits were contaminated there.

Officials said the contamination showed the agency violated standard manufacturing protocols.

Problems could also be a sign of an agency in a hurry, experts said.

““I’m not surprised that they encountered some setbacks right after.” “They were asked to increase production in a way that I wasn’t sure was asked before.”

The authors report that problems with early testing have prompted the CDC to implement a “more thorough and rigorous review process” in developing a new test that can detect both the coronavirus and the flu. The new test was tested in all three public health labs to make sure it worked.

“Since the first Covid-19 test was made available, the CDC has implemented corrective measures and remains committed to the highest quality of laboratory science and safety,” the agency said in a statement.

Dr. The bigger lesson, Butler-Wu said, is that responsibility for developing diagnostic tests needs to be more widely distributed during a public health emergency. Authorities can also commission clinical and commercial laboratories to create and distribute tests, rather than relying on the CDC as the sole test developer.

“It’s great to have all these additional controls in place, but what do you do when there’s a new pathogen emerging and we need to respond quickly?” said. “I don’t think this is a suitable model for responding to a pandemic.”