Vaccinated? Now don’t go looking for antibodies

An antibody test after vaccination is no yardstick to judge protection against Coronavirus experts have cautioned especially since there have been instances of fully vaccinated people finding no antibodies in their system raising doubts on the effectiveness of vaccines The warning comes at a time when antibody tests are being advertised for homeuse Experts say incorrect interpretation of the test results might prompt some fully vaccinated people to lower their guard against Covid19ldquoWhile a positive antibody test result can be used to help identify people who may have had prior SARSCoV2 infection or resulted from vaccine shots more research is needed to know whether this test can pick up yet an undetermined category of neutralising antibodies that will provide protection for the future That is because the currently authorised SARSCoV2 antibody tests have not been evaluated to assess the level of protection provided by an immune response to Covid19 vaccinationrdquo says Dr Subhash Hira Professor of Global Health at the University of WashingtonSeattleDr Hira said ldquoIf antibody test results are interpreted incorrectly there is a potential risk that people may take fewer precautions against SARSCoV2 exposure even after completing the vaccine shots Thus taking fewer steps to protect against SARSCoV2 can increase their risk of SARSCoV2 infection and may result in the increased spread of SARSCoV2rdquoAlso Read Mumbai BMC wonrsquot have more vaccination centres for students going abroadThe expert made a few recommendations for those who have had an antibody test1 Antibody tests help healthcare providers identify whether someone has antibodies to SARSCoV2 indicating a prior infection with the virus However more research is ongoing to understand the meaning of a positive or negative antibody test including in people who received a Covid19 vaccination 2 If you have not been vaccinated Positive result does not mean you have a specific amount of immunity or protection It means that it is possible you were previously infected with the SARSCoV2 virus 3 If you are vaccinated Covid19 vaccine shots may also cause a positive antibody test result for some but not all brands of antibody testsCalling the correlation between antibody test results and protection due to vaccines ldquoprematurerdquo Dr Hira said ldquoI feel that SARSCoV2 antibody tests should be ordered only by health care providers who are familiar with the use and limitations of the test rather than just through an accessonline productrdquoDr Wiqar Shaikh Professor of Medicine Grant Medical College and Sir JJ Group of Hospitals said the human body has an efficient ldquoimmune systemrdquo to fight off bacteria and viruses and it produces ldquoneutralising antibodiesrdquo helpful only for a short periodbetween the virus entering the body and then entering the cells of an individual Inside the cells antibodies have no role and it is the job of Tcells to kill the virus infected cellsDr Subhash Hira professor of Global Health at the University of WashingtonSeattleDr Shaikh added that in India Covid19 is being caused by a ldquomutationrdquo of the original virus He explained that when a virus multiplies inside a cell it makes an error during multiplication which results in a change in its genetic code Mutation makes it more difficult for the virus to be detected and treated and results in a spike in cases increased hospitalisation and more deaths He emphasised that antibodies are unable to attack a mutated virus and canrsquot prevent it from entering the cellDr Shaikh expressed surprise over media reports discussing the role of antibodies in Covid19 infection particularly following vaccination He said he is amused that people sued vaccine manufacturers saying their shots did not produce antibodies The role of Tcells which is of paramount importance in Covid19 infection and protection following vaccination has been completely ignored he addedDr Shaikh cited a November 2000 publication in the Journal of Virology USA which says that ldquoantibodies play little or no role in controlling viral infectionsrdquoHe quoted another article in Science Daily of March 2012 that said ldquoantibodies are not required for immunity against virusesrdquo A publication from the Centre for Evidence Based Medicine Oxford University in October 2020 said that ldquoit is the Tcell response which bodes well for longterm immunity in Covid19 infectionrdquo he saidIn July 2020 lsquoNaturersquo journal used data from patients infected with the older SARSCoV virus in 2003 to conclude that the infection induced a durable Tcell response lasting up to 7 years but did not produce a longterm antibody response An important finding from this study was that the Tcells from the 2003 infection were shown to kill Covid19 virus 17 years after the original infectionIt is important for Covid19 vaccines to stimulate a robust Tcell response he said adding ldquoMeasuring antibodies after a vaccine dose is of little value and it is imperative to study Tcells following administration of Covid19 vaccinesrdquo