HYDERABAD: Last week I got a very excited call from a friend who said she has developed COVID-19 antibodies. And then another cousin called feeling dejected that he has no antibodies yet. Both had not been previously tested for coronavirus. What is this new fascination for knowing if we have developed COVID-19 antibodies and the false sense of security that follows it?
My friend says while she was getting a Thyroid test, the phlebotomist suggested she get this additional test, as it is “in-trend” now. This antibody blood test is cheaper than the mandated RT-PCR to check for a current COVID-19 infection, and the result comes back within 24 hours. She says the positive result gives her a sense of hope and confidence to travel, meet more people, do stress-free shopping, and get back to work from the office.
What does having the COVID-19 antibody mean? Dr Pragathi, lab director and consultant microbiologist, Medicover Hospital, Madhapur explains, “If one has COVID-19 antibodies, it means their immune system fought the infection and has developed these antibodies against the coronavirus.” Dr Ramanaprasad VV, consultant pulmonologist, KIMS Hospital adds, “However, it fails to tell us if they have fully recovered and are no longer infectious, or if they are safe from reinfection.”
The World Health Organization has also warned against issuing “immunity passports” to people who have recovered from COVID-19, as there is no evidence that they will be protected from a second infection.
Despite the limitations of the test and the uncertainty over the results, increasing numbers of people are getting the tests done. “Wondering if I have already encountered COVID-19, and if that provides me with immunity made me take this test,” said my cousin.
Karan Kurani, co-founder and CTO, DoctorC says, “We have seen people get antibody tests to see whether they have been exposed to the virus. However, a negative test does not necessarily mean that they don’t have any antibodies.”Dr Pavani Tushara Garapati, technical and operational head, Previa Health Pvt Ltd shared, “We are getting around 175-200 antibody requests until now.”Having antibodies does not mean you cannot get re-infected
Most people’s lives have hit a pause button due to the pandemic and they want to resume their lives. Based on this test they feel they have some security. Some people falsely think testing positive on an antibody test proves they can’t get infected with the virus again. Having antibodies against the coronavirus is no guarantee that you won’t pick up or pass along an infection, warn experts.
“Antibodies can differ with the time you get tested and show wrong results. However, that doesn’t mean they aren’t effective. It could be a part of the community-driven response to the pandemic,” shares Dr Pragati. However, she adds, “Even if one has antibodies, do not assume you are invulnerable to the new coronavirus. Clouding the interpretation of a positive antibody test is that we do not yet know if antibodies make people immune to a reinfection. We also don’t know how much of these antibodies are needed to ensure protection.”
Dr Ramanaprasad VV, consultant pulmonologist, KIMS Hospital, sounds a warning. He says, “I don’t encourage antibody testing for every patient as a positive test report may give them a false assurance that they are immune to a second infection and may ignore the public health advises.”
Dr Pavani says, “Taking antibody tests could certainly make people negligent and ignore the threat of the COVID-19. If you do take a test, you should be looking out for its sensitivity. Antibody tests can offer preventive satisfaction, but do not guarantee any conclusive proof that you are fully safe from the virus. It is best to continue to follow all social distancing norms, use a good quality mask, frequent hand washing and sanitisation.”
Who should get tested for antibodies?
Dr Pragati recommends that, “Antibody testing should be done in individuals who have COVID- 19 symptoms, but did not have immediate access to a COVID-19 PCR test.” She adds, “It is not recommended for those within 8-10 days of symptom onset.”
Dr Ramanaprasad says, “In my opinion antibody testing should be advised to people who are about to undergo any surgical procedure who were previously tested positive for COVID-19 and also for people coming forward to donate plasma.”
Differences between RT-PCR, antigen and antibody tests
RT- PCR:
The real-time polymerase chain reaction (RT-PCR) test is the most commonly used test for COVID-19 detection which is primarily based on PCR, a process that repeatedly copies and amplifies the specific genetic fragments of the virus. RT-PCR is mainly conducted with a simple swab taken from inside a person’s throat or nose.
Antigen:
These tests are designed to detect a specific protein in the virus that elicits the body’s immune response. For this test, professionals collect a nasal swab, which is then immersed in a solution that deactivates the virus. A few drops of this solution are then put on a test strip. Antigen tests that have been approved for COVID-19 diagnosis in India give results in 30 minutes.
Antibody test:
Also known as serological tests, detect whether a person has antibodies to the virus. Antibodies are naturally produced by the body’s immune system to fight off infections. Antibody tests cannot be used to diagnose COVID-19, but can reveal whether a person who was recently exposed to the virus, has developed immunity against the COVID-19 virus.
- Dr Pavani
— Tamanna S Mehdi
tamanna@newindianexpress.com
@tamannamehdi