The WCBS is currently performing a SARS-CoV-2 Seroprevalence study. This study tests for the presence of antibodies to SARS-CoV-2, the virus that causes COVID-19.
What are antibodies?
Antibodies are proteins made by the immune system to fight infections like viruses. SARS-CoV-2 is the virus that causes COVID-19. After a person is exposed to SARS-CoV-2, the immune system can take days or weeks to develop antibodies and it is not known how long these antibodies remain in the blood.
Are antibodies used to diagnose COVID-19?
An antibody test detects the presence of antibodies to a specific infection and not the presence of the actual infection. An antibody test will not show if you have a current COVID-19 infection because it can take 1–3 weeks after infection for your immune system to make antibodies.
To diagnose current SARS-CoV-2 infection, a molecular test (PCR) is required. This test uses samples taken mostly from the nose and throat using a long swab.
If my test result says that SARS-CoV-2 antibodies are detected, what does this mean?
If SARS-CoV-2 antibodies are detected, it is possible that you have recently or previously had COVID-19. You may test positive for antibodies even if you have never had symptoms of COVID-19. This can happen if you had an infection without symptoms, which is called an asymptomatic infection. There is also a small chance that this is a false positive result, because antibody tests may detect antibodies to a different virus from the same family of viruses (called coronaviruses).
If SARS-CoV-2 antibodies are detected, does it mean I am immune to COVID-19?
The presence of SARS-CoV-2 antibodies does not necessarily mean you are immune from SARS-CoV-2 infection, as it is not known whether having these antibodies will protect you from getting infected again.As new variants are being detected in South Africa and internationally, antibodies to one variant may not necessarily provide immunity to another variant.
If my test result says that SARS-CoV-2 antibodies are NOT detected, what does this mean?
You may not have ever had COVID-19.
There is also a chance that you have had COVID-19 previously and didn’t develop antibodies. Some people take longer to develop antibodies and some people may never develop antibodies even though they have had COVID-19 infection. In addition, you may have had a previous COVID-19 infection but no longer have detectable antibody levels due to the time since your illness.
Regardless of whether SARS-CoV-2 antibodies are detected or not, this does not confirm whether you are able to spread the virus that causes COVID-19. Until we know more, continue to take steps to protect yourself and others.