The supply of molecular tests for COVID-19 across the nation is somewhat limited, causing local officials to look into a different kind of testing: serology testing.
Molecular testing is what has been broadly used to diagnose COVID-19: it determines whether an individual exhibiting symptoms has the COVID-19 virus at the time of testing. The test is performed by inserting an oral or Nasopharyngeal swab up the nose and at the back of the throat to collect material. It is then sent off to a lab to look for the protein coated DNA and RNA material of the virus.
This test has been known to have a 30% false negative rate and can take 4-7 days for a lab to process, however it is approved by the Food and Drug Administration.
Serology testing is a newer and faster method of testing that takes as little as 15 minutes to process. At this time only one serology test is FDA approved. This test takes a finger prick and looks for antibodies in the blood that indicate some level of immunity has been built.
The FDA issues a disclaimer with all serology tests that negative results do not rule out an infection and that it should not be used as a sole basis to diagnose or rule out a COVID-19 infection.
The molecular test, used locally by labs and clinics, can diagnose 2 days after infection. The serology test can find positive antibodies after a minimum of 7 days, but still may not find positive antibodies at that time.
Serology tests were first used as confirmatory testing to supplement the molecular tests because initially molecular tests were not very accurate, City of San Marcos Emergency Management Coordinator Rachel Ingle said. Once the CDC had enough data to confirm all the molecular tests were performing properly, they discontinued the serology testing for confirmatory purposes.
After getting viruses like the flu, individuals develop antibodies that protect them from becoming reinfected by the virus for a certain period of time, but not forever. It is common practice for people to get a flu vaccine every year because the flu virus mutates every year and the vaccine is adapted to those mutations. The vaccine creates an antibody response that boosts immunity and protects them from the flu season that year. Because of the virus’s ability to mutate, there will never be 100% immunity, Dr. Jay Zdunek, Chief Medical Officer at the Austin Regional Clinic explains. After getting a virus like the Chicken Pox, individuals develop antibodies that protect them from being reinfected for the rest of their life. The benefit of serology testing is that it allows us to determine who has been exposed and who has antibodies available, the challenge is that because this virus is so new, it is unknown how long immunity will last.
“Further down the road, once we get past our response efforts, we can get to a point where we can start collecting and analyzing data from serology testing for future responses and determine what percentage of the population we believe to have had the virus at some point in time. That can tell us what the second or third wave will look like in August when people start going back to school or work and how the virus will continue to circulate in our community the same way that the flu virus does,” said Ingle.
Serology testing provides a snapshot of what percentage of the community has an immunity to the virus, but without knowing how long the immunity will last, it’s hard to use serology testing as a predictive measure, Zdunek said.
“When you look at countries that have been successful in mitigating the spread, it’s been through molecular testing, in the form of knowing who has been infected and then doing contact tracing and isolating the contacts to prevent them from spreading it to other people," Zdunek said. "Serology testing for antibodies will be useful in being able to help ease people’s fears as we go along.”
Hays County has been conducting contact tracing for positive COVID-19 cases as needed.
County Judge Ruben Becerra would like to utilize mass serology testing to understand how deeply COVID-19 has penetrated the community and begin to make a plan for how to get Hays County back to work.
“My first priority is public health, and my second priority is getting our businesses back. My role is to bring resources to the county so that the medical professionals can utilize them,” he said.
Telehealth apps and other startup companies are advertising COVID-19 testing that can be provided by speaking to a medical professional on an app. Becerra currently has 2,000 tests on hold with a telehealth app called MDBox where you can pay $50 to see a physician virtually and get scheduled to be tested at a yet to be organized drive-through clinic for COVID-19 if your symptoms meet the CDC criteria for being tested. They do not accept insurance.
A representative from MDBox said, “We continue to consider a drive-through testing model in San Marcos but have not yet confirmed the location. Once our site is selected, if our medical professionals decide you should be tested you would be assigned a timeslot to drive through the testing event.”
Zdunek said it’s important to understand the difference between the two tests if you are seeking medical care from someone other than your primary care doctor. Many of these 15 minute tests are serology tests which will not show up positive for at least 7 days after the infection began and may not show positive antibodies at all.
“Serology has a place but not a place for making diagnosis,” Zdunek said.
MDBox has advertised COVID-19 testing that has been confirmed to be serology testing. According to a press release from MDBox, “All Hays County community members will have access to the MDBox.com mobile application and be able to purchase these in-home COVID-19 tests at partner retail locations after completing a video chat with a healthcare provider.”
According to Dr. Amy Altman on March 31, residents in Hays County can perform at home testing because Becerra decreed it in his emergency declaration, however no at-home testing is FDA approved. In the April 14 Commissioners Court meeting, Altman said, “We are not offering in home testing, we are offering telehealth drive through testing,” despite no drive-through testing sites currently scheduled.
Becerra clarified that he approved of telemedicine, seeing a doctor at home through the phone or a video call, and that he has not been interested in home test kits. “I believe the way out of this is through mass testing, and I’m supporting and pushing and encouraging purchasing all tests we can get our hands on as long as they are vetted through medical clearance and dispensed by medical professionals.”
U.S. Congressman Raja Krishnamoorthi (D-Il.) and Representative Katie Porter (D-Ca.) have opened a an investigation into MDBox’s parent company, Reliant Immune Diagnostics and AnyPlace MD for allegedly selling at-home test kits.
Zdunek said that medical facilities need testing supplies just as much as they need personal protective equipment.
“We would love to have more PPE, especially when it comes to protecting the people who are putting their life on the line for citizens every day.” Representatives from Premier ER and Urgent Care, Premier Research Laboratories and My Emergency Room 24/7 echoed his request.
From an emergency management perspective, Ingle urged the county to invest in PPE rather than tests in Commissioners Court Tuesday. Ingle has stated that we have enough tests to test those who need to be tested according to CDC guidelines — so far that has been around 600 tests for Hays County with around 500 negative. Premier Research Laboratories has been running the county testing site for first responders and medical personnel and confirmed they could use more tests but have enough to conduct the tests that have been ordered each day.
“We don’t want to waste our resources. If an individual tests positive, there is no need to test the other individuals they live with. The virus is contagious enough, it is assumed that they are positive. The actions are going to be the same whether you test positive or not: stay home and self quarantine for 14 days,” Ingle said.
Individuals with COVID-19 symptoms who test negative are still recommended to take the same precautions as if they tested positive, isolate for at least 7 days since symptoms began and 72 hours without fever without the use of fever-reducing medications.
Concerns over mass testing inundating the labs are unfounded, as labs, ERs and hospitals are actually seeing 20%-80% fewer patients, according to Dr. Zdunek who predicts the economic fallout of COVID-19 to drastically change the landscape of medicine in Central Texas. Labcorp and Quest Diagnostics have capacity to test 40,000 to 45,000 COVID-19 test per day.
Zdunek encourages people to contact their healthcare providers for the most accurate information. He comments that government officials have done the best they can with the availability of information. When it comes to making a plan for reopening, whether that’s utilizing serology tests or not he said, “I don’t know that we will be able to on an intellectual level ever be able to predict the exact date when everybody is safe. We have to make decisions that are mindful of all components, recognizing that the world has to go on.”
People manage the anxiety of the flu and pneumonia every year despite taking thousands of lives. He says we will learn more with time and learn from what is happening in other societies and adapt as we go.
“At some point our positive case counts will start to taper off and decrease. As more people recover from the virus, the number of active cases will drop when that’s consistently the case over a longer period of time, that’s when we will know we have hit our peak," Ingle said. “At that point we will know that the virus is not actively continuing to spread through the community and we have antibodies for it. That is when we can look at how we open things back up. Right now the projections expect cases to pick back up and the next wave should be around August when kids go back to school and people go back to work. We have to prepare for that. If we open everything up at once we are setting ourselves up for failure there.”
