Is there any point in getting a Covid-19 antibody test?

Dis-Chem and Clicks recently started offering Covid-19 antibody tests at their clinics for R150 and R199 respectively. Both health retailers promise rapid test results — a mere 15 minutes in Dis-Chem's case.

But what exactly do these tests determine and why would you want to get one?

First, a Covid-19 antibody test is not a Covid-19 test and it won’t tell you whether you are actively infected with the virus. Rather, these tests can be used to determine whether you've developed antibodies in response to having previously contracted the Covid-19 virus.

Second, it is important to understand that just because the test might pick up that you have antibodies against Covid-19 doesn’t mean you’re immune from the virus.

Speaking to TimesLIVE earlier this year, Dr Kgosi Letlape, president of the Health Professions Council of SA, explained that some people who have already had Covid-19 may become reinfected.

“This means the antibodies were not protective — or that even though they’d had the infection, they didn’t develop a good enough immune response to protect them [from it] in the future.”

A study published by The Lancet journal last month outlined the case study of a man who became infected with Covid-19 twice — and whose second infection was much worse than the first.

“All individuals, whether previously diagnosed with Covid-19 or not, should take identical precautions to avoid infection with SARS-CoV-2,” the study read.

According to the department of health’s website, antibody tests may be useful for research. For example, antibody testing can be used to reconstruct the chains of transmission in outbreak settings, to better understand the true number of infections that occurred during the peak of a country’s Covid-19 outbreak, or to assess Covid-19 vaccine responses.

Antibody testing is also useful to diagnose multi-system inflammatory syndrome in children and to identify people who have had Covid-19 in order for them to donate blood plasma for the treatment of Covid-19 patients.

For the most part, antibody testing is aimed at people who may have presented with symptoms but never got tested and are curious as to whether they've had the virus, or people who may have had the virus and were unaware of this because they were asymptomatic.