By Gary Evans, Medical Writer

In a move widely seen as further evidence the pandemic response has been politically undermined, the Centers for Disease Control and Prevention (CDC) recently revised SARS-CoV-2 testing guidelines, de-emphasizing the need to test asymptomatic people who have been in contact with a case of COVID-19.1

The response from the infectious disease community was swift and severe, with many arguing that decreasing testing during a pandemic makes no sense and will lead to more infections.

“In a dramatic shift from previous federal guidelines, the CDC disclosed that some people without COVID-19 symptoms may not need to be tested, even though they may have been in close contact with an infected person,” Georges C. Benjamin, MD, executive director of the American Public Health Association, said in a statement. “This is inconsistent with the evidence that shows up to 40% of individuals who are infected spread the virus asymptomatically. It is also unclear what problem this change solves.”

The revision created an immediate problem for CDC Director Robert Redfield, MD, who tried to walk back the change by issuing a statement that conceded testing may be “considered” for all close contacts of confirmed or probable COVID-19 patients.

“We are placing an emphasis on testing individuals with symptomatic illness, individuals with a significant exposure, vulnerable populations including nursing homes or long-term care facilities, critical infrastructure workers, healthcare workers and first responders, or those individuals who may be asymptomatic when prioritized by medical and public health officials,” Redfield stated. “Testing is meant to drive actions and achieve specific public health objectives. Everyone who needs a COVID-19 test can get a test. Everyone who wants a test does not necessarily need a test; the key is to engage the needed public health community in the decision with the appropriate follow-up action.”

Testing, or lack thereof, has hobbled the U.S. response since the outbreak began. The CDC previously cited potential transmission from asymptomatic cases in emphasizing the importance of testing contacts of those with COVID-19. Posted Aug. 24, the revised language reads:

“If you are in a high COVID-19 transmission area and have attended a public or private gathering of more than 10 people (without widespread mask-wearing or physical distancing): You do not necessarily need a test unless you are a vulnerable individual or your healthcare provider or state or local public health officials recommend you take one.”1

In his statement, Redfield summarized testing recommendations and mitigation techniques as follows:

  • Testing may be considered for all close contacts of confirmed or probable COVID-19 patients.
  • Symptomatic or asymptomatic contacts who test positive should be managed as confirmed COVID-19 cases.
  • Asymptomatic contacts testing negative, or who are not tested, should strictly adhere to CDC mitigation protocols.
  • If testing is not available, symptomatic close contacts should self-isolate and be managed as probable COVID-19 cases.

Anyone who has been in close contact with a confirmed or probable COVID-19 patient should follow these mitigation tactics:

  • Monitor symptoms;
  • Take special precautions to protect the vulnerable;
  • Wear a mask;
  • Stay at least six feet apart;
  • Wash hands;
  • Talk to a healthcare provider or public health expert determine if testing is needed.

Mixed Messages

The CDC action in part could be a real-world acknowledgement of the lack of rapid testing nationwide. But it drew a strong reaction because of a general perception that testing methods were improving and it would become easier to test contacts of suspected or confirmed COVID-19 cases.

“This has me and many other people in infectious disease and public health scratching our heads, because we were moving as a society to expanding testing,” says William Schaffner, MD, a professor of preventive medicine at Vanderbilt University. “As testing becomes more available, less expensive, and the results can be returned more quickly, we were moving to greater use of tests — not reducing testing.”

One problem is that tests — depending on the test used and conditions under which it is given — may result in a false-negative, or less often, a false-positive. “False-negative tests provide false reassurance, and could lead to delayed treatment and relaxed restrictions despite being contagious,” wrote Robert H. Shmerling, MD, senior faculty editor of Harvard Health Publishing. “False-positives, which are much less likely, can cause unwarranted anxiety and require people to quarantine unnecessarily.”2

For example, the commonly used polymerase chain reaction (PCR) test with a nasal swab results in a range of false-negatives (2% to 37%). The reported rate of false-positives with this test is 5% or lower, Shmerling noted.

“The outside of the incubation period for [SARS-CoV-2] is 14 days,” Schaffner says. “That is a very long period. We have all been trying to think of strategies that are valid and science-based to try to abbreviate that. We recognize that there is no perfect answer, but could we still reduce that duration and provide some assurance that the risk is very low?”

One tactic is to provide more testing to address the situation with false-negative tests. “There might be a way to do testing more frequently. If they are negative for several days, I would think that would reduce the risk that this contact is going to become positive,” he says. “I thought we as a public health community were moving in that direction, trying to find testing as a means of providing some assurance that people could come out of quarantine a bit earlier. That is in conjunction with trying to move us back into a more functional society. This set of [CDC] advisories would appear to put the brakes on that.”

Another troubling aspect of the testing change is the CDC presented no new data indicating spread from asymptomatic carriers is less of a concern than previously emphasized.

“I haven’t seen any new data, but of course we understand a person who is a contact and quarantined is not likely to be a transmitter,” Schaffner says. “[As a result of this change], we will be identifying fewer positive individuals.”

Will this translate to more transmission? “Of course — exactly,” he says.

Changes ‘Indefensible’

Indeed, asymptomatic cases play a significant role in transmission of the novel coronavirus, said the Infectious Diseases Society of America. “The [CDC] revision is concerning, particularly as the United States continues to lead the world in confirmed cases and deaths, with more than 5.8 million cases and nearly 180,000 lives lost to the virus,” the IDSA said in a statement. “Identifying individuals infected with COVID-19 — even if they are asymptomatic — is critical to support appropriate isolation and identification of contacts, to limit spread, and to provide the data-driven, comprehensive view of community spread needed to inform effective public health responses.”3

The Society for Healthcare Epidemiology of America (SHEA) “vehemently” disagreed with the CDC testing changes, calling for an “immediate revision of these guidelines to underscore the criticality of testing and contact tracing as a primary means of combating the pandemic.”

On the contrary, the country needs “dramatically increased testing,” SHEA emphasized in a statement. “While the exact timing of such testing in relation to exposure can be debated, broad-scale testing is critically important because COVID-19 has been proven to be transmitted frequently by asymptomatically and pre-symptomatically infected persons.”4

While acknowledging “the constraints of current testing capabilities,” SHEA said the CDC is retreating from a basic principle of public health during outbreaks.

“The revised CDC guidelines are in direct contradistinction to evidence-based public health guidelines for identifying new cases of an epidemic disease, aggressively tracing contacts of new cases, and isolating and testing contacts known to be exposed,” SHEA stated. “These principles are cornerstones of the public health management of an infectious disease epidemic.”

SHEA urged the CDC to rescind the revised guidelines immediately and “include exposed contacts as individuals who need not only quarantine but also testing.”

In a tweet, Tom Frieden, MD, former director of the CDC, called the revision “indefensible.”

“If an asymptomatic contact tests positive, their contacts can be identified, warned, and quarantined,” Frieden said. “Not testing asymptomatic contacts allows COVID to spread. The CDC guidance is indefensible. No matter who wrote it and got it posted on the CDC site, it needs to be changed.”5

In his statement issued after the guidelines were revised, Redfield said, “CDC recently updated some of our testing guidance to reflect updated recommendations as to who should be tested. These updated guidelines, coordinated in conjunction with the White House Coronavirus Task Force, received appropriate attention, consultation, and input from task force experts.”

In a bizarre note that seems only fitting during the tragedy of errors that has been this nation’s pandemic response, Anthony Fauci, MD — arguably the most respected infectious disease physician worldwide — told CNN he was literally unconscious during a surgical procedure when the testing revisions were made.

“I was under general anesthesia in the operating room and was not part of any discussion or deliberation regarding the new testing recommendations” said Fauci, a member of the White House Coronavirus Task Force and director of the National Institute of Allergy and Infectious Diseases. “I am concerned about the interpretation of these recommendations and worried it will give people the incorrect assumption that asymptomatic spread is not of great concern. In fact, it is.”6


  1. Centers for Disease Control and Prevention. Overview of Testing for SARS-CoV-2 (COVID-19). Updated Aug. 24, 2020.
  2. Shmerling RH. Which test is best for COVID-19? Harvard Health Publishing. Aug. 17, 2020.
  3. Infectious Diseases Society of America. IDSA/HIVMA Statement on Changes to CDC Guidance. Aug. 26, 2020.
  4. Society for Healthcare Epidemiology of America. SHEA Statement on Changes to CDC Testing Guidance. Aug. 27, 2020.
  5. Frieden T. Twitter. Aug. 27, 2020.
  6.  Diamond J, Holmes K, Gupta S. Fauci says he was in surgery when task force discussed CDC testing guidelines. Aug. 27, 2020.