Understanding the Different Types of Testing for COVID-19
The coronavirus continues to spread, and patients are sadly losing their lives to this terrible virus every day. While we still have a long way to go, medical experts are working hard to chart a path forward.
There are two different types of testing: viral tests and antibody tests. They are both important for gaining control of the outbreak.
A viral test is usually done using a nasal swab. This test detects the presence of the live virus in your body, whether or not you are showing symptoms of COVID-19. It is used to identify active cases that may be contagious, whether or not the person is having any symptoms.
An antibody test is a blood test used to determine if a person has been previously infected. This test measures the level of antibodies in the blood, which may be a marker of immunity.
Current Testing to Diagnose Active Infections (Virus Testing)
While testing availability continues to grow in the United States, there are still limits in supplies and capacity to test all people who may be infected with the virus.
- In mid-May, the U.S. was conducting up to 400,000 tests per day. Public health experts have estimated that it will take somewhere between 500,000 to 20 million tests per day to safely reopen the country.1
- The goal is to have far less than 10% of tests be positive. This would suggest that enough tests are being done to make an accurate assessment of the level of infection in the community. Once that benchmark is achieved, the goal is to sustain or continue to lower the percentage of positive cases over 14 days. In mid-May, the percentage of positive cases was about 8% in the U.S., down from roughly 21% in April.1 In some hot spots, the percentage of positive cases still ranges between 15 and 20%.
- In addition to virus testing, contact tracing is an important aspect of containing the virus. This is the process of finding and informing people who may have come in contact with an infected person so that they can be tested and quarantined if needed. Setting up a system for contact tracing will require a large workforce. Experts estimate that 180,000 new personnel would be needed to perform this work nationwide.
- States are running low on vital public health and testing resources, including trained staff, materials, machinery and personal protective equipment (PPE), and are having trouble getting resupplied.
The Future of Antibody Testing
Antibodies are proteins produced by our immune system to help stop intruders like the novel coronavirus from harming our body. An antibody test for the novel coronavirus could help doctors and researchers understand what percentage of the population may be immune. The higher this percentage, the closer we come to herd immunity. Herd immunity occurs when enough people have immunity, either because they have already had the disease or have been vaccinated, that the virus can no longer easily spread from person to person. Experts are still trying to understand, however, what level of antibodies in someone’s blood means that he or she is immune from getting a second coronavirus infection or how long that immunity will last (yearly like influenza or life-long like measles).
- As of May 5, we do not know whether immunity can result from having COVID-19 or, if it does result, how long that immunity will last.
- Researchers are working on a blood test that can identify COVID-19 antibodies, and, in doing so, are trying to determine the level of antibodies necessary for immunity and whether certain types of antibodies are more protective than others. While there are multiple tests on the market, several tests do not work.8
- Conducting this research is challenging and time-consuming.
- Until we produce accurate tests that indicate immunity, we cannot identify who is immune and whether communities have achieved a protective level of herd immunity.
Vaccination Is Key to Eradication
The development and widespread distribution of an effective vaccine will allow people to achieve active immunity without the risk of experiencing severe illness from COVID-19.
- Many scientists are dedicating time and effort to researching possible vaccines.
- Infectious disease experts estimate that it will take 12 to 18 months to develop a vaccine, and some believe it will take even longer. When researchers are able to develop an effective vaccine, the effort to achieve herd immunity will come easier and quicker.
The American Lung Association’s Response
We remain focused on our mission to save lives by improving lung health and preventing lung disease through research, advocacy and education. The COVID-19 pandemic has resulted in one of the highest rates of lung infections and deaths in recent history. To save lives and decrease the risk of a generation of COVID-19 survivors with severely damaged lung health, we are calling for the urgent nationwide rollout of coordinated and universal testing.
“The more people you can test, the more accurately you can determine who is potentially safe from the virus and who is spreading it to others,” said American Lung Association Chief Medical Officer Albert Rizzo, M.D. “This effort becomes even more important as control measures such as social distancing are relaxed. The more you can do that, the more you can stop the virus from spreading further, saving lives and decreasing the post-COVID risk of chronic lung disease.”
Let us all continue to do what we know is working: Stay home. Stay safe. Save lives.
- The COVID Tracking Project. US Daily Cumulative Totals. https://covidtracking.com/data/us-daily. May 20, 2020.
- Allen D, et al. Roadmap to Pandemic Resilience; Massive Scale Testing, Tracing, and Supported Isolation (TTSI) as the Path to Pandemic Resilience for a Free Society. https://ethics.harvard.edu/files/center-for-ethics/files/roadmaptopandemicresilience_final_0.pdf. Published April 20, 2020.
- Lopez G. The 4 plans to end social distancing, explained. Vox. https://www.vox.com/2020/4/14/21218074/coronavirus-plans-social-distancing-end-reopen-economy. Published April 14, 2020.
- Aubrey A. Which States Are Doing Enough Testing? This Benchmark Helps Settle The Debate. NPR. https://www.npr.org/sections/health-shots/2020/04/22/840526338/is-the-u-s-testing-enough-for-covid-19-as-debate-rages-on-heres-how-to-know. Published April 22, 2020.
- Opening Up America Again. The White House. https://www.whitehouse.gov/openingamerica/#criteria.
- How We Reopen Safely. https://www.covidexitstrategy.org/. May 20, 2020.
- Slavitt A, Gottlieb S, et al. April 2020. https://apps.npr.org/documents/document.html?id=6877567-Bipartisan-Public-Health-Leaders-Letter-on.
- Morrison S. Why America's coronavirus testing problem is still so difficult to solve. Vox. https://www.vox.com/recode/2020/4/24/21229774/coronavirus-covid-19-testing-social-distancing. Published April 24, 2020.
- Test for Past Infection. Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/testing/serology-overview.html. Published May 5, 2020.
- Neergaard L. Big unknowns about virus complicate getting back to normal. AP NEWS. https://apnews.com/44654e29f03076bfb721f79e5deb4fe8. Published April 21, 2020.
- Yglesias M. The US needs more urgency on developing a coronavirus vaccine. Vox. https://www.vox.com/2020/4/27/21231717/coronavirus-vaccine-development. Published April 27, 2020.
Blog last updated: May 22, 2020