Currently, there is a great deal of confusion among the public and government officials regarding COVID-19 testing during the surge of the Omicron variant. Questions about the accuracy of testing, who is infected with the Omicron variant, when should the tests be administered, and which tests should be done are difficult questions to answer because the scientific data about testing is still emerging. While data in science needs time to accumulate, medical and government policies must be formulated as quickly as possible even if they have to be modified or changed in the future. The lack of answers to these questions leads to public confusion about how to live, test, and quarantine during this latest outbreak of COVID-19. At this point in time, more research needs to be done concerning testing and yet, the public needs to be given clear guidelines. In order to help establish guidelines, politicians need to enhance their knowledge of COVID 19 and Omicron testing.
There are essentially three types of tests that can be performed to possibly detect COVID-19. The most accurate may be the Polymerase Chain Reaction (PCR) test. This test needs to be done in a certified laboratory and involves amplifying the possible presence of unique COVID-19 RNA sequences that are contained in a nasal or throat swab. PCR results can tell you what variant you have and are usually obtained within a day or two but may take several days. A PCR test usually costs about $150 without insurance. This test is highly sensitive and can detect small samples of both live or dead viruses but cannot by itself determine whether a patient is currently infected with live viruses.
The rapid, “do-it-yourself” home test, also known as antigen tests, usually involves swabbing the nose to detect unique proteins that only the COVID-19 virus expresses. The test takes about 15 minutes to display the results on a test strip provided in the kit and costs about $20 for a package of two tests. Because the test does not magnify the COVID-19 proteins, a positive result usually means that the individual recently produced a high number of viruses but it does not differentiate between live and dead viruses. In addition, many at home tests do not tell the patient what variant of COVID-19 they have.
Antibody tests , which are not commonly used to test for present infection, determines the presence of specific antibodies that an individual has produced in response to exposure to COVID-19 or Omicron. Often, samples can be taken from a finger prick at home and sent to a lab at a cost of less than $70. These blood antibody tests are not routinely used to diagnose COVID-19 for several reasons. First, having a positive antibody test only informs the physician that the patient had been exposed to COVID-19 but does not reveal whether the patient is currently infectious. Antibodies can remain in a person’s blood for at least eight months after exposure to the virus before waning. However, I believe antibody tests will become more useful in the future especially if we can develop inexpensive methods to assess the actual levels of antibody and not merely the presence of antibodies. For example, determining the current antibody levels of individuals who have received two vaccine doses, or who have recently recovered from the Omicron variant, will help physicians decide whether the patient requires a booster or whether the patient’s recovery from a COVID-19 infection has generated high levels of anti-COVID-19 antibodies.
The accuracy of home tests that detect the presence of COVID-19, especially Omicron, is in part a function of how the test sample was obtained. The Omicron variant tends to lodge in the throat so that obtaining only a nasal sample for the test may not be sufficient. Science needs to establish whether samples obtained from both gently swabbing the nasal passage and coughing into the swab are more accurate. However, having patients perform throat swabs themselves may not be a safe procedure for patients whereas physicians are trained in obtaining throat swabs. Again, it is important to stress that this test does not differentiate between live or dead viruses.
Because current tests do not necessarily inform the physician whether the patient is infectious, it is important to ascertain what symptoms, if any the patient experiences before determining how long, if at all, the patient needs to be in quarantine. It may not be unreasonable to first perform a PCR on a patient experiencing mild symptoms and then a home COVID test after the symptoms subside. How often a PCR test is performed depends on the asymptomatic or symptomatic status of the individual. The information obtained will be helpful to asses how long a patient should quarantine, if at all? Again, more data has to be gathered to determine how long the isolation period should be. Until that data is obtained, government policies should opt for longer periods rather than shorter periods as they follow the number of Omicron cases. In addition, some countries, such as the UK no longer require recovered patients to take a follow-up PCR.
Here, the Centers for Disease Control and Prevention (CDC) and media need to inform the public of clear guidelines with the recognition that these guidelines could change. The public can understand changing guidelines as we have observed with travel bans and mask mandates. I believe the public can accept changing PCR and home testing guidelines, and quarantine rules as well, if they are presented clearly. The CDC website has a lot of useful information but it might be improved if it included a new detailed section on testing guidelines.
