Amid false positives and false negatives, widespread misinformation and distrust of coronavirus tests and vaccine efforts, some Americans are hesitant and confused when it comes to getting tested.
Just last week, Ohio Gov. Mike DeWine falsely tested positive for the coronavirus, or COVID-19, ahead of his visit with President Donald Trump, as reported by the Washington Post, deepening public skepticism of test accuracy.
In a Tuesday, Aug. 11 press conference held by the Association of State and Territorial Health Officials, several U.S. health experts gathered virtually to answer coronavirus-related questions addressing where the U.S. is with testing and where it falls short.
Here is what they discussed.
Categories of COVID-19 tests
A diagnostic test is used to determine if individuals have an active coronavirus infection and should take steps to isolate themselves from others. There are two types of diagnostic tests: molecular and antigen.
Jennifer Nuzzo, senior scholar and associate professor at the Johns Hopkins Center for Health Security, said the most commonly used diagnostic test is a molecular test—otherwise known as a polymerase chain reaction or RT-PCR test. This method uses a nasal or throat swab to detect the genetic material of the virus.
An antigen test uses a nasal or throat swab to detect specific proteins on the surface of the virus. Nuzzo said while antigen tests yield more rapid results—sometimes within the same day—and “positives” are highly accurate, there is an increased chance of false negatives compared to molecular tests.
It is possible for tests to be inaccurate based on the way they were conducted at home or by medical professionals, as well as their level of sensitivity, which is the ability of a test to correctly identify those with the disease, she said.
Nuzzo said one of the biggest drawbacks of coronavirus testing is the results only reflect a person’s status at the time they were tested, meaning someone could initially test negative but go out and contract the coronavirus by the time they receive their test results a day or a week later.
She said this is why it is important for people to receive better communication about what test results mean and for individuals to quarantine after they are tested.
Guidance from the Centers for Disease Control and Prevention states that the people who really need to be tested are those with symptoms, those who have traveled to an at-risk country or state and those who have been in contact with someone who has the coronavirus.
An antibody test is a blood test that determines whether one has coronavirus antibodies in their system and has thus had the coronavirus at some point in time. It cannot tell a person whether they actively have the coronavirus or if they are now immune to it.
Public Health Surveillance
Eric Blank, chief program officer of the Association of Public Health Laboratories, said to get things under control, the country eventually needs to be able to track the virus on a population-based scale using contact tracing, diagnostic test results and other methods of surveillance.
He said by identifying coronavirus hotspots, public health officials can provide vulnerable populations such as minority groups or nursing home residents with necessary services—including testing—on a more regular basis.
“From a public health perspective, we don’t need to test everybody,” Blank said. “We need to know where the disease is.”
Blank said public health entities should frequently work with commercial and private health care providers and laboratories to benefit communities and meet the needs of businesses and schools.
Supply and demand issues
One of the biggest issues since the early weeks of the coronavirus pandemic has been a shortage of supplies, from gloves and masks to testing kits.
Blank said there are around 30 items that go into making a coronavirus test, and if any of these items are missing due to a supply chain issue, it becomes impossible to conduct the test.
Because a lot of products used for coronavirus testing—such as pipette tips, specialized swabs and chemicals—are the same as generally-used laboratory supplies, Blank said coronavirus laboratories are often in competition with other analytical labs for the same products.
He said another problem is that the ongoing and extreme demand for testing overwhelms manufacturers because they were not prepared for the high surge in demand and are only built for a certain volume of components.
Blank added major manufacturers of supplies in the U.S., China and Northern Italy were all hit hard by the pandemic.
Nuzzo said there has not been a national audit to address any roadblocks in the country’s testing capabilities, leading many states to negotiate with foreign governments to gain access to potentially life-saving supplies.
Rachel Levine, secretary of health at the Pennsylvania Department of Health and president of the Association of State and Territorial Health Officials, said while the number of available tests has increased since March and April, there will continue to be shortages due to the demand, leading to longer wait times for test results in some instances.
The national average wait time for coronavirus test results is 4.1 days, according to an August survey by researchers from Harvard University, Harvard Medical School, Northeastern University, Northwestern University and Rutgers University. This number fluctuates based on one’s ethnicity and state.
Testing in workplaces and schools
“We don’t recommend that a college test every student … or a large business test everybody through the diagnostic system because it generates thousands of tests, which then potentially makes it more difficult when we’re trying to test symptomatic people,” Levine said.
Instead, Levine said a better use of available resources and technology is sample pooling, where small groups of people are tested as one “batch,” and if the pool is positive, it means one or more of the individuals in the pool may be infected.
Nuzzo said she has “deep concerns” about institutions testing everyone as a way to send people home from work and school based on test results that are hard to interpret and may be inaccurate.
“A number of businesses and organizations have basically kind of developed their own plans without really coordinating with health authorities,” she said.
Moving forward into flu season
Levine said vaccinating against the flu will be “critically important” this year as people should avoid potentially getting both the coronavirus and the flu, which are two respiratory viruses that can cause severe illness and even death.
Since influenza testing is done through health care providers in the private sector, Blank said public health officials should also consider using rapid flu and rapid coronavirus tests at the doctor’s office level to boost public health surveillance and track the spread of the flu along with the coronavirus.
Nuzzo said overall, testing guidelines are not something that should be decided on a state-by-state basis because it makes large-scale disease prevention efforts more difficult.
“People have been pushing the federal government to develop a national testing strategy that not only defines what we are supposed to be doing with the tests we have and what should our approach to testing be, but what is the current capacity,” Nuzzo said. “And if it’s insufficient, how do we fix it?”