Cycle Threshold Value Missing in CCP Virus Case Numbers: Experts

EqualTox lab workers process COVID-19 tests in Tustin, Calif., on Sept. 3, 2020. (John Fredricks/The Epoch Times)

News Analysis

Since the beginning of the CCP (Chinese Communist Party) virus pandemic, policymakers in the United States have relied heavily on the daily positive cases—confirmed by an RT-PCR test—in their policy decisions regarding when states can fully reopen.

With infection rate being such a major criterion in determining when these states can reopen, it is paramount for test centers to report not only the positive test result of a PCR test, but also the cycle threshold (Ct) value that measures the viral load.

The cycle threshold value is the number of amplifications it takes the test machine to detect the virus’s genetic material, providing valuable information on whether a person is infectious or at risk of severe symptoms from COVID-19.

“The lower the number of cycles, the more of the virus is present,” Dr. William W. Li, an internationally renowned physician, scientist, and author of New York Times bestseller “Eat to Beat Disease: The New Science of How Your Body Can Heal Itself,” told The Epoch Times in an earlier interview. “The higher the number of cycles needed to pick up signs of the virus, the less is present.”

Knowing the cycle threshold of a PCR test allows government and public health officials to better gauge if there is a serious spread of the virus occurring in an area and take appropriate action, instead of only resorting to lockdowns.

While proponents of lockdowns say that it plays a role in slowing the spread of COVID-19, many others, including prominent experts, are warning against such extreme measures.

Dr. David Nabarro, the World Health Organization’s (WHO) Special Envoy on COVID-19, urged world leaders to not use lockdowns “as the primary means of control of this virus,” in an interview with The Spectator earlier this month.

“The only time we believe a lockdown is justified is to buy you time to reorganize, regroup, rebalance your resources, protect your health workers who are exhausted, but by and large, we’d rather not do it,” Nabarro said.

More than 40,000 medical practitioners and scientists from around the world who agree with Nabarro have signed the Great Barrington Declaration, which states that “current lockdown policies are producing devastating effects on short and long-term public health. The results (to name a few) include lower childhood vaccination rates, worsening cardiovascular disease outcomes, fewer cancer screenings and deteriorating mental health—leading to greater excess mortality in years to come, with the working class and younger members of society carrying the heaviest burden.”

The declaration also garnered the support of over 500,000 citizens concerned with the numerous negative effects of the lockdowns.

Concerns of fake names signing the declaration are being addressed by the authors of the declaration. They wrote on the website, “The fake signatures are less than 1 percent of the total, and most have been removed from the count tracker.”

White House officials told reporters in a conference call on Oct. 12 that the president’s policy—centered around protecting the high-risk elderly and vulnerable, opening schools, and restoring society—aligned with what “top epidemiologists and health policy experts have been saying—that is, lockdowns do not eliminate the virus; lockdowns are extremely harmful.”

EqualTox lab workers process COVID-19 tests in Tustin, Calif., on Sept. 3, 2020. (John Fredricks/The Epoch Times)

No Standard Cycle Threshold Value

There is no universal standard cutoff cycle threshold value for the PCR tests being used throughout the country for a positive diagnosis, as the federal government does not make that decision.

A spokesperson for the CDC wrote in an email to The Epoch Times that, “The Ct cutoffs for various PCR-based assays are defined as part of each test’s FDA emergency use agreements (EUAS)—they are specific to each test.”

“In general, CDC does not develop Ct cutoff guidance as this is typically innate to the tests (some of which are likely proprietary). CDC’s guidance is around the original assay that our lab developed.”

The threshold value cutoff for the CDC’s PCR test is 40 cycles, a value that many medical experts believe returns false positives, as fragments of a killed virus may be picked up.

The cycle threshold cutoff for many of the manufacturers of PCR tests in the Foundation for Innovative New Diagnostics‘ independent evaluation of various PCR tests is set at around 40 cycles for a positive sample.

In a document [pdf] from the Kansas Health and Environment Laboratories, the cycle threshold value cutoff for the PCR test used in the state was revealed to be 42 cycles.

When asked about the high cycle threshold cutoff value, Kristi Zears, director of communications at the Kansas Department of Health and Environment, told The Epoch Times in an email, “The Ct value is determined by the manufacturer of each test to maximize the sensitivity of the respective test. We have used and continue to have multiple systems being used that may have different cutoffs, but all have been validated to determine presence or absence of the virus.”

What the cycle threshold cutoff value should be varies in discussions among the scientific community, but generally ranges between 25 and 30 with agreement that patients cannot be contagious above these numbers.

Two earlier studies that successfully cultured the CCP virus from positive samples, found a correlation between virus viability in cell culture and cycle threshold value of a PRC test.

One study of 90 positive COVID-19 samples, showed “no positive viral cultures with a Ct greater than 24 or STT [symptom onset to test] greater than 8 days. The odds of a positive culture were decreased by 32% for each unit increase in Ct.”

Another viral culture study of 183 positive samples from 155 patients from the Méditerranée Infection University Hospital Institute in Marseille, France, reported that patients with threshold values at 34 or above did not “excrete infectious viral particles.” The study also showed that infectiousness was greater with Ct values of 13-17, while at a 33 Ct, the culture positivity rate was only 12 percent.

In the most recent study published in Clinical Infectious Diseases, researchers examined 3790 positive COVID-19 samples with known Ct values to find if any could be cultured in vitro. They found that for samples with Ct values of 25 or below, around 70 percent could be cultured, meaning that a higher viral load is correlated with being more contagious.

PCR Test Sensitivity Leads to False Positives

PCR tests are known for their sensitivity to detect the smallest virus particle, regardless of whether it is a live or nonviable virus, and amplify it millions of times, which can then result in an overdiagnosis of COVID-19.

In updated guidance for healthcare workers, the Centers for Disease Control and Prevention (CDC) said that data shows “that if the person who has recovered from COVID-19 is retested within 3 months of initial infection, they may continue to have a positive test result, even though they are not spreading COVID-19.”

Dr. Christy Risinger, an Internal Medicine physician in Texas, says in a video about COVID-19 testing, “PCR, as I mentioned, looks for fragments of RNA, so it’s very sensitive, but it may be overly sensitive for COVID-19.”

“We know that after about one week of infection from SARS-CoV-2, people are no longer infectious to others, but they still will be positive with PCR testing because they’ll still have bits of the virus within their body.”

SARS-CoV-2 is another name for the CCP virus that causes COVID-19.

According to a case report, a patient continued to test positive on a PCR test for 62 days after symptom onset, although the “virus could not be isolated after the 18th day.”

In a different case study, a registered nurse tested positive for COVID-19 for 29 days, while she had been asymptomatic for 23 days after symptom onset. She was only able to return to work after she was determined noninfectious since her last PCR test had a CT value of 38.

Emel Akan contributed to this report.