No Ka Oi Health
There are a couple of tests for COVID-19 — the Nasopharyngeal (NP) swab and the antibody test. This article aims to shed light on what the results of each test mean and when you should consider getting either.
The NP swab is the test you would get when you think you are currently ill with COVID-19. If the results are positive, you likely have an active COVID-19 infection and need to isolate yourself to prevent infecting others. If the results are negative, you don’t have an active COVID-19 infection. This test does not tell you if you’ve been infected in the past or could get COVID-19 in the future.
The NP swab tests have been mostly limited to testing people with COVID-19 symptoms and/or people associated with COVID-19 clusters. With the limitations of these tests, they don’t offer information about how many asymptomatic carriers of COVID-19 there are in our community.
The antibody test is a blood test that tells you if you have had a prior infection. This test, however, can’t tell you how long ago you had the infection, if you are still infectious, or if you are immune to COVID-19. If you test positive with the antibody test, you will need to follow-up with a NP swab to determine if you are currently infectious.
Since the antibody test is not used to “diagnose” current infections, insurance companies are not currently covering the cost of this test. If you want an antibody test, you will need to pay for it yourself, which could cost at least $100 per test.
It’s important to note that even if you test positive for antibodies, you may not have immunity to COVID-19 and could potentially get infected again.
Since the antibody test doesn’t tell you if you are infectious, then why get one?
Researchers and public health departments may use the antibody test to learn more about COVID-19. This research helps us learn the total number of cases in a community, specific neighborhoods most affected, percentage of asymptomatic cases, whether asymptomatic cases are infectious, and the true fatality rate of COVID-19. Moving forward, antibody tests will be critical for scientists to learn how the COVID-19 virus works and how to fight this pandemic.
Q: When should you get a NP swab or antibody test?
You should only get an NP swab test if you believe you are currently ill with COVID-19, if you have been recently exposed to a person who is confirmed positive with COVID-19, or if you have a high level of exposure to vulnerable populations (i.e., nursing homes).
Currently, the antibody test is primarily helpful to scientists and researchers who are interested in learning about the spread and prevalence of COVID-19 in an entire community. For the information from these tests to be helpful, a random and representative sample from the entire community needs to be tested, not just individuals choosing to get tested.
Q: Can people get COVID-19 again if they’ve had it in the past?
The simple answer is that we don’t know. For some illnesses, antibody tests tell us who has immunity and is not at risk for getting infected in the future. For COVID-19, we don’t know yet if people carry long-lasting immunity after becoming infected. In fact, the Centers for Disease Control and Prevention issued guidelines stating that antibody tests “should not be used to determine if an individual is immune,” but should only be used to determine demographic and geographic patterns of COVID-19.
Regardless of whether you have had COVID-19 already or not, we each need to focus on preventing getting exposed and spreading illness. Stay home if you are ill and stay away from ill people; clean your hands and high-use surfaces often; avoid touching your face; cover your coughs and sneezes; and avoid crowds. Further, wear a mask and practice physical distancing even if you are don’t feel ill. To protect each other, we need to err on the side of caution and act as if asymptomatic carriers can spread COVID-19. Remember, you wear a mask to protect me, and I wear a mask to protect you.
For more information about COVID-19 tests call Public Health Education at (808) 984-8216.
* Kristin Mills is public health educator with the state Department of Health’s Maui District Health Office. No Ka Oi Health is published on the fourth Thursday of the month by the state Department of Health.