Lynne Katzmann headshot
Lynne Katzmann, Ph.D.

For those with limited time or patience, here is the punchline: Rapid, widespread testing is the only way to outrun COVID-19 short of an effective, widely distributed vaccine.

COVID-19 has been clouded in a deep fog since it was first identified in Wuhan, China, in December. What we knew almost immediately was that it was highly contagious and could be lethal, particularly for individuals with underlying health conditions, most notably hypertension, heart disease and diabetes.

COVID-19 is a novel virus, meaning it is a virus we have not had the pleasure of experiencing before. Because it severely affects the respiratory system, public health officials early on issued guidelines consistent with those that worked for SARS in 2003. In the 2003 SARS epidemic, the disease was spread only by individuals who were symptomatic. The epidemic was controlled by symptom-based detection and testing that, in turn, provided a guide to isolation and quarantine.

And so, initially, guidance for COVID-19 seemed clear: test those who were symptomatic, conduct contact tracing, and isolate or quarantine exposed individuals to stop the spread of the disease. But according to the New England Journal of Medicine, we now know that COVID-19 is a disease of the upper respiratory system rather than the lower, where the SARS virus thrived. It is now believed that viral shedding occurs more easily and earlier from the upper respiratory tract. This may explain, at least in part, why COVID-19 is more readily spread asymptomatically.

It also now is clear that the screening protocols put in place at healthcare facilities were necessary but insufficient to stop the spread of the virus. They were designed to identify those with known symptoms such as fever. People were screened at the door and halted from entering if symptomatic. This was inadequate given that the spread of COVID-19 is both insidious and invisible.

Testing is the only way to identify asymptomatic carriers.

But not all testing is the same.

Two very different types of tests

There are essentially two types of tests that do very different things. The first are those that detect the active presence of the virus. The second are those that detect antibodies produced in response to the infection.

The first group, which detects the active virus, has two distinct test types: 1) RT-PCR (PCR), commonly known as the swab or sputum tests, and 2) isothermal nucleic acid amplification tests.

The PCR tests currently are most prevalent and involve taking a sample from an individual and sending it to a lab for processing. Depending on the lab, the results generally are promised within 24 to 48 hours. Unfortunately, given the large number of tests and the small number of labs, wait times for results are often much longer, particularly now given the current surge in cases.

An alternate test for active COVID-19 typically is called the rapid test. Although there are several varieties of these tests, the results usually are available in either minutes or hours. The most well-known of these, Abbot Diagnostics ID NOW, was given an emergency use authorization, or EUA, from the FDA on March 27. The Abbot Diagnostics tests have come under scrutiny lately, however, due to a high number of false positive and false negative results. There are now 4 EUA-approved tests of this type that may be performed outside of a moderate or high complexity lab.

The second group of tests detects antibodies to COVID-19. These tests provide a snapshot that shows how many people have had the disease, including those who were/are symptomatic. These tests also are known as serology tests, and as of July 12, 28 laboratories had received their EUA from the FDA. The tests look for two different antibodies, IgM and IgG, which are believed to be generally detectable in the blood several days after infection. These antibody tests are being used to determine what part of the population already has contracted the virus and may therefore be immune. Unfortunately, there is no evidence that antibody presence means immunity or if immune, how long that immunity will last.

The Centers for Disease Control and Prevention provides data on the number of laboratories that offer COVID-19 testing. As the data indicate, the number of labs has increased dramatically in the past several months. Unfortunately, even with this ramp-up, we continue to face shortages, particularly for viral tests. In addition, with cases increasing across the nation and demand for testing growing, the processing time has gotten longer, meaning that people with the virus may be in transmitting it while waiting for results.

Together, these two types of tests — viral and antibody — are essential to gain a clear picture of disease spread in the United States.

The front line includes senior living

Early during the crisis, primarily due to short supply, tests were provided first to hospitals and other “front-line” healthcare professionals. Unfortunately, the current definition of front-line healthcare professionals is only now beginning to include senior housing. Unlike hospitals that care for those already sick, we are home to Americans who are both more susceptible to the harsh consequences of this virus and those who, when sick, use most of the hospital resources. If we want to outrun this virus, then we need to keep these Americans safe and, to the greatest extent possible, COVID-19-free.

The best way to do this is to make sure that everyone coming in contact with these people is disease-free. And the only way to do that without a vaccine is a test to ensure that those in contact do not have the active, communicable virus. The way to do that is to test. And to test everyone who has not recovered from the disease, every day. 

I still believe that we are the greatest country, capable of amazing efforts for the public good. We need to put our efforts into rapid testing, make it widely available until a vaccine is ready, and prioritize our greatest and silent generations and their caregivers.

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