What and Why Antibody testing should be done post Covid 19 vaccination?
When an invader like the SARS-CoV-2 coronavirus enters a person’s body, cells called B lymphocytes create antibodies to protect the individual. These antibodies stick around to defend against the invader in case it ever comes back. The role of these antibodies can be protective and as evidence to the exposure of Covid- 19 or after vaccination. Vaccines teach the body to mimic this response and prime the immune system for a fight against the invader. Thus, it sets the stage for a situation where when a virus attacks the body, the immune response would be swift and adequate.
It might be tempting to undergo an antibody test days after getting a Covid-19 vaccine. People want to have travel plans and long-delayed reunions with loved ones. Some are curious to explore the tests as a way of checking whether their vaccines are working. But it is not a necessity. Antibody production after a vaccine shot varies from person to person depending on several biological factors.
Some may have an immediate response while others may show a delayed response to the vaccine.
The COVID-19 vaccine trains immune cells to notice and attack the signature spike protein as most of the vaccines are focused on the coronavirus spike protein and its variants as the primary antigen of COVID19 infection.
Hence, a test involving S protein should be used to find out whether antibodies have developed in the individual. Other tests detect antibodies to a different part of the virus called the nucleocapsid protein, which is produced in response to infection but not by the current vaccines.
However, antibody tests should not be used at this time to determine immunity or protection against COVID-19 at any time, and especially after a person has received a COVID-19 vaccination.
Though it is not recommended, but the presence of antibodies still denotes a person’s immune response towards the virus. which means they may be at lower risk for future infection. These people having antibodies may still have reinfection, but the chances of severity become less.
Importantly, the covid-19 vaccine may confer protection that goes beyond antibodies.
There’s not just one arm of the immune system. In addition to the antibodies that are generated after vaccination, people also generate T cell immunity. These T cells are equally important, but harder to measure and not reflected in antibody tests. These cells are needed for long-term protection.
These T cells might not be able to prevent Covid infection unless there is a low level of virus, but they are important for clearing the virus from the body once the infection has occurred.
Antibodies alone can protect, including at relatively low levels, but T cells are also helpful if antibody levels are insufficient. Such knowledge will be important in the development of next-generation vaccines, antibody-based therapeutics, and public health strategies for COVID-19.
The best thing we can do right now is to get the Covid-19 vaccine and continue to follow standard mitigation measures to avoid exposure to the virus.
(This article is attributed to Dr. Ramesh Kinha, Chief Pathologist, Medall Healthcare Pvt Ltd)
(Disclaimer: The opinions expressed in this article are those of the author. They do not reflect the views of India TV)
