How often will you need a COVID vaccine?
Coronavirus or the SARs-COV-2 virus has impacted the lives of millions. While scientists and medical professionals continue to search for an answer to eradicate the disease, it's unpredictability is what has become a source of concern and chaos. From new emerging variants to a rise in the number of breakthrough infections, many factors have compelled people to doubt the effectiveness of COVID vaccines.
Some experts believe that vaccine-acquired immunity may fade over a period of time, which is why talks and discussions around COVID vaccine boosters have become prevalent. On the other hand, some people also want to know whether or not they'll have to take a COVID shot every year, given that vaccine immunity may diminish.
We have some established doctors, who will clear out all your doubts and provide some useful insights into what we can expect in the future.
COVID vaccines are administered in two doses, booster shots trial is underway
In India, the COVID vaccines available are Bharat Biotech's Covaxin, Serum Institute's Covishield and Russia-made Sputnik V vaccines, which are all administered in two doses. While Covishield's second dose can be taken after a gap of 12 weeks, you can get your second Covaxin dose between an interval of 4-6 weeks. As per latest reports, Russia's Sputnik V can be administered in two doses with a 21-day gap.
However, in India and abroad, the quest to develop vaccine boosters is ongoing. Israel and the United States of America are the first countries to have started administering the third dose of COVID vaccine in people who are immunocompromised.
Read more: COVID-19 herd immunity? It's not going to happen, so what next?
Do vaccine-induced immunity wane over time?
Given that fully vaccinated people are also getting infected with the virus, experts have signaled towards the possibility of waning immunity.
According to Dr. Anup R Warrier, Senior Consultant, Infectious Disease & Infection Control, Aster Hospitals, India, "Vaccination triggers our immunity at 2 different levels- an early B-cell mediated antibody response and a delayed T-cell mediated response."
"Sustainability of vaccine related immunity is dependent on how the individual responds to the vaccine, how efficient and effective the T cell response is going to be, whether the virus mutates over time to evade the kind of antibodies produced by the primary vaccination," he adds.
Keeping all these factors into consideration, Dr. Warrier suggests that vaccination-induced immunity may wane in terms of antibody levels over time.
Read more: Vaccine-induced COVID immunity versus natural immunity: Which protects you better?
Role of Vaccine boosters
Vaccine boosters have gained a lot of momentum in recent times. Considering breakthrough infections have become prevalent and new variants continue to emerge every now and then, the demand for a booster dose is increasing. The administration of a booster shot is expected to re-expose a person's immune system to the immunizing antigen, the memory of which (following previous doses) could have been lost over a period of time.
Dr. S.N Aravinda, Consultant - Internal Medicine, Aster RV Hospital, JP Nagar, Bengaluru also agrees that vaccine-induced immunity may wane over time. This is why, according to her, "Most vaccines have a certain time period beyond which another shot is required in order to reactivate the immune system to produce antibodies, providing protection against a particular disease."
He further highlights the fact that all existing COVID-19 vaccines have been recently developed and each vaccine has been made distinctly. "Depending on clinical trials and findings, vaccines that are producing antibodies for a duration of 8 months to a year may only require booster shots every few months to keep the immunity going," he says.
Will COVID shots become an annual affair? Will we need boosters on a regular basis?
While immunity from COVID vaccines may dwindle over time, experts believe that we may need to boost your immune system frequently.
Dr. Aravinda states, "Depending on clinical trials and findings, vaccines that are producing antibodies for a duration of 8 months to a year may only require booster shots every few months to keep the immunity going."
"After a point ideally people will develop herd immunity and vaccination will no longer be required," he explains.
On the contrary, Dr. Warrier believes it is too early to comment on a possible booster schedule. However, he agrees that we will need a vaccine booster over time. How often we will need it will depend on "long term data on breakthrough infections and development of newer variants of concern," he says.
Is there a difference between a regular COVID shot and vaccine boosters?
COVID vaccine boosters are an extension of COVID-19 vaccines. It is also known as a third COVID vaccine dose too.
The vaccine doses are the same, says Dr. Aravinda. "The only difference is the time duration at which it is given. Booster shot is given when the effects of the first round of vaccination are expected to decline. Regular covid shot is given to ensure that sufficient antibodies are produced to fight the Covid-19 virus, if exposed to it," he explains.
Additionally, given that vaccine boosters may "invoke a more sustained antibody response" (protective levels over longer duration), it can protect against prevailing variants, says Dr. Warrier. However, more research is needed to prove the same, he adds.