Need for Booster Dose 

By Shyam Sunder

Globally, as of 6 January 2022, there have been 296,496,809 confirmed cases of COVID-19, including 5,462,631 deaths. The memory of the devastation caused during the second wave of coronavirus is not only disturbing, but it fills us all with a sense of fear and insecurity.  Once again, with COVID-19 cases rising, it’s time to get booster doses if you’re eligible. But you might be wondering whether you and your family members actually need a COVID booster shot or not and, if you do, how to go about actually getting one.

India has already approved more than six vaccines to fight against COVID-19. In India’s vaccination drive,  three vaccines Covishield, Covaxin and Sputnik V were involved and the rest are approved for cases of emergency. Bharat Biotech, a Hyderabad-based pharmaceutical company which is the manufacturer of Covaxin has suggested that it has 78% efficacy.  However, recently,  Dr Naveet Wig, Professor and Head of Medicine at AIIMS mentioned that the two doses of Covaxin is only 50% effective in preventing systemic infection. This efficacy is lower than 77.8% which was claimed by Bharat Biotech during 3rd phase trials.  At the same time, the Oxford-AstraZeneca vaccine Covishield is made from a weakened version of the common cold virus. Covishield efficacy was measured around 53.28% after the administration of the first dose. However, it’s efficacy is increasing up to 60-80% in 8-12 weeks after the administration of the second dose.  

Similarly, Sputnik V vaccine has been developed by Gamaleya National Research Center for Epidemiology and Microbiology Russia, which consists of two different adenoviral vectors as an expression of SARS-CoV-2 spike protein gene. Sputnik V with 96% efficacy rate is the third vaccine which received approval for emergency use in India after Covishield and Covaxin.

I would like to point out that vaccines offer strong protection and boosts the immune system to fight against viruses. People must take all the required doses of a vaccine to build full immunity. For a two dose vaccine if you are vaccinated with only a single dose then you are just partially protected. 

It’s also true that vaccines do not provide full protection so breakthrough infection can happen. But as more people get vaccinated, it is expected fewer people will come in contact with the virus.   Currently, Omicron cases are increasing day by day. Now is the time everyone must look at getting a booster dose. You must be thinking of a booster as a third dose but one thing you have to know is that all the doses after the first dose are considered as a booster dose. It depends on their efficacy in electing immune response.

The World Health Organisation states that a booster is necessary for the older people, frontline workers and immunocompromised individuals. The main objective of a booster dose is to restore vaccine effectiveness from that deemed no longer sufficient. Booster is an additional dose; it is recommended because it was observed that protection against mild and moderate COVID-19 via the initial vaccine series declines over time . 

So who are eligible for booster: 

· People who are vaccinated some time ago

· People who are immunocompromised

· If your antibody titers are low then you are also eligible for booster dose

· If your vaccine efficacy is low

· Booster is only administered after the two doses of Covaxin or two doses of Covishield or one dose of Sputnik V.

India is already witnessing the third wave of the COVID-19 pandemic, according to Dr N K Arora, who heads the Covid working group of National Technical Advisory Group on Immunisation (NTAGI). A total of 1,892 cases of Omicron variant of SARS-CoV2 virus have been detected across 23 states and union territories so far, according to the Union Health Ministry’s data early this week. Omicron spreads very rapidly and several times faster than Delta. The daily case positivity has risen 0.79% on Dec 29 to 5.03% on January 5. The NITI Aayog Member (Health) Dr. VK Paul stated that those who have been administered Covishield and Covaxin will receive the booster dose of the same vaccine. Primarily, a booster is given to the front line workers, 60+ people and people with comorbidities.

The clinical trials are going on booster dose. The government has decided to give the same vaccine as a booster because there is no scientific evidence on mixing up vaccines. As per sources this also means that the third dose for an individual who has been double vaccinated with Covishield cannot be Covaxin, and vice versa. The same would apply to Sputnik V as well.