Tonight, I’d like to refer you to a remarkable article in the Wall Street Journal that chronicles the missteps at the Centers for Disease Control that delayed COVID-19 testing for three weeks in February. This delay certainly contributed to a lack of understanding of how widespread the disease was in the United States, but also left institutions and individuals powerless to know who had COVID-19 infection. The report also documents how molecular (PCR+swab) tests detect the SARS-CoV-2 virus in excellent graphics and explains exactly what went wrong with the CDC test.
The CDC test uses the polymerase chain reaction (PCR) Technique to amplify the genetic material from the SARS-CoV-2 virus. This test was similar to tests that were developed in other parts of the world, particularly in Europe, but the components were made entirely by the CDC. As shown below the test amplifies the genetic material for the virus and incorporates a fluorescent signal that can be detected by the device running the test. The greater the fluorescent signal the more virus genetic material is present. See below.
In the United States the CDC was responsible for producing the first PCR assay to detect the virus. The CDC’s test was to become the reference standard that the other test developed in the USA could be judged by. While other laboratories were capable of developing a PCR test, they were prohibited from doing so until the CDC standard was available. Thus, when the CDC test failed it essentially halted all other test development in the United States.
The article lists a number of things that went wrong with the introduction of the assay. These include:
– The CDC test, which the FDA authorized on Feb. 4, shipped by Feb. 6 to 33 states and 70 labs in 66 countries, according to an HHS report. One of the reagents to detect Coronavirus was contaminated with viral genetic material so that it always came up positive. This component was not specific to the new coronavirus, but looked for genetic material present in all common coronaviruses, a fail-safe in case the virus mutated.
-It was unclear what caused the problem, and the CDC was examining all aspects of the test, which was very time consuming.
-The CDC Director, Dr. Robert Redfield, gave continually moving timelines as to when the test would be fixed.
-Timothy Stenzel, the FDA official in charge of lab diagnostics, examined the CDC’s Respiratory Virus Diagnostic Lab in Atlanta, where the test was developed, on Feb. 22. What he saw there was alarming, his boss Jeffrey Shuren, the FDA’s medical-device center director, said in a later HHS conference call as recounted by a senior administration official. In the call, Dr. Shuren described the lab as “filthy”—meaning it had the potential to be contaminated—the official said. If it had been any other lab, Dr. Shuren told CDC officials on the call, the FDA would have shut it down. This was the likely source of the contamination.
-The CDC considered remanufacturing the entire test, but that would have delayed the test until mid-March.
-Finally, on February 26th, the CDC decided to allow the test to be used without the “fail-safe” contaminated component.
-During the interim, the CDC did not allow tests from other countries to be used in the US.
-The test design turns out to be fine as LabCorp used it to develop their own assay. That assay worked well without the contamination.
While there is some disagreement as to how seriously this failed test disrupted the United States response to the pandemic, it is striking that the top public health organization in our country would make such a grievous error. This story suggests that there should be a high-level review of the CDC, particularly their laboratory facilities. Also, a reorganization with better oversight of operations is in order.
Regardless, an error like this cannot be allowed to happen the next time we face a pandemic.