COVID vaccine: Till when do antibodies last? Do we need booster dose?

Bhubaneswar: Dr. Narendra Kumar Arora, Chairman of COVID-19 Working Group of the National Technical Advisory Group on Immunization (NTAGI), today answered the questions regarding the longevity of antibodies after receiving COVID-19 vaccine and necessity of taking booster dose.

Question: Till when do antibodies last in the body? Do we need to take a booster dose after some time?

Answer: After vaccination, the immunity that has been developed can obviously be ascertained by the development of antibodies which can be visible and be measured. Apart from this, an invisible immunity is also developed. It is known as T-Cells which possess memory power. Henceforth whenever this virus will try to enter, the entire body becomes alert and starts to act against it. Thus, having antibody is not the only sign of our body’s immunity power. Hence, there is no need to do antibody tests after vaccination, get worried and lose sleep over it.

Secondly, COVID-19 is a new disease which surfaced just one and a half years ago and it has just been 6 months since when vaccines are being given. But it seems that, like all other vaccines, immunity will last for at least six months to a year. With the passage of time, our understanding of COVID-19 will improve. Moreover, certain factors like T-Cells cannot be measured. It has to be seen as to till how long after vaccination people can be saved from serious illness and mortality. But, for now, all vaccinated individuals will remain safe for six months to a year.

Question: Once we have taken a particular company’s vaccine, do we have to repeat that particular vaccine only? If we have to take booster doses in the future, then also, should we have the same company’s vaccine?

Answer: Instead of companies, let us talk about the platforms. It never has happened before in human history that different processes and platforms have been used to develop vaccines for the same disease. Since the manufacturing processes are different for these vaccines, their effect on body will also not be the same. The process of taking different types of vaccine in two doses, or again a different vaccine later in a booster dose (if required), is called interchangeability. Whether this can be done is an important scientific question. Steps are being taken to find an answer to it. We are one of those rare countries where different types of COVID-19 vaccines are being given. This sort of interchangeability can be accepted or recognized only for three reasons: 1) It increases or betters immune power, 2) It eases the program of vaccine delivery; 3) Safety is ensured. But this interchangeability should not be propelled by the reason of scarcity of vaccines as vaccination is purely a scientific phenomenon.