The public health agency with arguably the most admired and emulated approach to combatting infectious disease outbreaks worldwide finds its latest advice on COVID-19 testing widely criticized and openly disregarded. Amid the worst pandemic in a century, the Centers for Disease Control and Prevention (CDC) is dispensing advice to those who say they will not follow it.
How did we get here? Painfully. In a move suspected by some as politically driven, the CDC recently revised SARS-CoV-2 testing guidelines, deemphasizing the need to test asymptomatic people who have been in contact with a confirmed or possible case of COVID-19 as of Aug. 24, 2020: “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,” the CDC guidelines state.1 (See “CDC’s Controversial Testing Changes.”)
After the uproar, CDC Director Robert Redfield, MD, issued a statement that said testing of asymptomatic contacts could be “considered” and offered an explanation for the change.
“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.” (Italics are Redfield’s.)
Despite the qualifiers and caveats in the guidance, the infection control and public health community was not having it. Retreating from the cardinal public health principle of contact tracing was met with criticism and open rebellion.
“I don’t think it will have much impact at all, and the reason is states are going to ignore the CDC guidance,” says Will Humble, MPH, executive director for the Arizona Public Health Association. “Our county health departments resoundingly said, ‘Pound sand.’ We are going to keep testing, we are going to encourage testing of asymptomatic contacts, and when they are positive, we are going get them in [quarantine], and we are going try to continue to find their contacts.”
After a surge of COVID-19 cases undermined contact tracing efforts in June and July, Arizona has gotten back up to speed.
“Now we are finally in a position where our counties do case investigations and do follow-ups and have effective contact tracing,” he says. “I just don’t see discouraging [testing] now that we have that in place. This makes zero sense to us.”
Connie Steed, MSN, RN, CIC, FAPIC, director of infection prevention and control at Prisma Health in Greenville, SC, said her organization is continuing to offer drive-by testing for the community.
“Testing continues to be encouraged in our community because I think public health and infection preventionists still feel that testing is helpful,” she says. “We have drive-by by testing that is done, most times, seven days a week for our community. We are going to continue that. We are not going to deemphasize it.”
Steed is president of the Association for Professionals in Infection Control and Epidemiology (APIC), which was one of 265 organizations that signed a letter to the White House Coronavirus Task Force calling for the testing changes to be reversed. (See“Infection Control, Public Health Groups Call for Action on CDC Testing Change.”)
“Forty percent of infections are asymptomatic,” she says. “That means that there is a large volume of individuals that we don’t know about, so they can be a significant source of transmission. So public health does contact tracing and those [who] are exposed need to be tested so we can effectively quarantine. The hospitals ensure isolation. We really feel it is important to continue encouraging testing.”
Testing also is decentralized in many states and counties, making it less likely that some sweeping change seen as counterintuitive will be broadly adopted, Humble adds.
“The key question is whether the CDC guidance will change the behavior of the managed health care plans,” Humble says. “If they stop paying for testing based on this guidance, I think it could have a real impact — but [I] don’t see health plans stopping payment.
Sometimes You Have to ‘Fall on Your Sword’
Beyond the logistics, the CDC’s public health credibility has been hurt by this decision, says Humble, who has been involved in public health for three decades.
“As a career public health guy, my perspective from the very beginning is that the CDC has an untarnished brand,” he says. “They were the most trusted brand within the federal government. We knew we could trust the CDC for evidence-based recommendations and analysis. That has changed over the last six months. I think, among public health people, the reputation of the agency is tarnished.”
Change in CDC leadership could eventually restore confidence in the agency, as the rank and file staff and career scientists remain respected, Humble says. As is the standard practice with changes in U.S. presidents, CDC Director Redfield was appointed by the Trump Administration. President Trump has publicly called for a reduction in SARS-CoV-2 testing.
“To me if you are in a senior leadership position, if you are Redfield, there are certain moments in time where you say, ‘This is worth falling on my sword for.’ Enough is enough and you have to take a stand,” Humble says. “And we haven’t — at least publicly — seen that from them. Maybe there has been a lot of pushback behind the scenes that we never knew about. That happens behind closed doors and you never see it. [What you do] see is such a puzzling decision by the CDC. It flies in the face of everything we know about this virus.”
Asked if the decision was the result of political pressure, Humble answers, “I can’t say that because I don’t know 100% for sure. What I can say is this decision is not evidence-based. That much I know.”
Steed says the change has caused confusion, given the CDC’s recent emphasis on testing asymptomatic contacts.
“The question that many of us have is where is that coming from?” she says. “Because if you look as recently as July, they were pushing this testing — then all of a sudden this changes several weeks later? That kind of change puts things in question. Some of us are concerned that this is being done not because CDC is necessarily thinking this is what is best. It may be that there is another influence there. [Testing reduction] has been a constant theme from the administration and it could have — in my perception — had some influence.”
Universal masking in hospitals helps protect against asymptomatic cases, and everyone is generally having temperature checks and asked about possible contacts with COVID-19 cases. Mask use by the public became politicized early in the outbreak and remains a divisive issue despite clear scientific evidence that they afford some protection in close conditions. In a discussion of whether masks should be mandated by law, a legal scholar addressed the larger issue of insulating the CDC from political influence in future outbreaks.2
“The CDC was marginalized because the president and the White House contradicted [the] CDC’s science-based advice and even refused to allow [the] CDC to issue certain guidelines like school opening guidelines,” says Lawrence Gostin, JD, of the O’Neill Institute for National and Global Health in Washington, DC. “We need to return to a landscape where political officials support science and key public health agencies like [the] CDC. COVID shows that we need national uniform legal standards and [the] CDC is best positioned to use science as the basis for new powers.”
Testing, or lack thereof, may have hobbled the U.S. response since the outbreak began. The CDC previously cited potential transmission from asymptomatic cases in emphasizing the importance of testing the contacts of those with COVID-19.
The CDC action could, in part, be a real-world acknowledgement of the lack of rapid testing nationwide, but it drew a strong reaction because there was 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 in Nashville. “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 the 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,” writes Robert H. Shmerling, MD, senior faculty editor of Harvard Health Publishing.3 “False positives, which are much less likely, can cause unwarranted anxiety and require people to quarantine unnecessarily.”
For example, the commonly used polymerase chain reaction (PCR) test with a nasal swab results in a range of false negatives from 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 of time. 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 of the strategies is to do more testing to address the situation with false negative tests.
“There might be a way to do testing more frequently, and if they are negative for several days, I would think that would reduce the risk that this contact is going to become positive,” Schaffner 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 that the CDC presented no new data indicating spread from asymptomatic carriers is less of a concern than emphasized previously.
“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.”
Asked if that translates to more transmission, he said, “Of course — exactly.”
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.”
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 contradiction 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.4 “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.”
Anthony Fauci, MD, a member of the White House Coronavirus Task Force and director of the National Institute of Allergy and Infectious Diseases, told CNN he was literally unconscious during a surgical procedure when the testing revisions were made.5
“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. “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.”
- Centers for Disease Control and Prevention. Overview of testing for SARS-CoV-2 (COVID-19). Updated Aug. 24, 2020. https://www.cdc.gov/coronavirus/2019-ncov/hcp/testing-overview.html
- Gostin LO, Cohen IG, Koplan JP. Universal masking in the United States: The role of mandates, health education, and the CDC. JAMA 2020;324:837-838.
- Shmerling RH. Which test is best for COVID-19? Harvard Health Publishing. Updated Aug. 17, 2020. https://www.health.harvard.edu/blog/which-test-is-best-for-covid-19-2020081020734
- Frieden T. Twitter. Aug. 27, 2020. https://twitter.com/DrTomFrieden/status/1299038119593902080
- Diamond J, Holmes K, Gupta S. Fauci says he was in surgery when task force discussed CDC testing guidelines. Updated Aug. 27, 2020. https://www.cnn.com/2020/08/26/politics/fauci-coronavirus-cdc-testing/index.html?utm_term=image&utm_medium=social&utm_content=2020-08-26T21%3A14%3A55&utm_source=twCNNp