Explained: Everything you need to know about Covovax

Experts say Covovax has many advantages over other booster doses

Covid nasal vaccine Representational image

For those who have already taken two doses of Covid vaccines--Covshield or Covaxin, might want to take the Covovax vaccine as a heterologous booster dose as per the recommendation of the Central drug regulatory authority Drugs Controller General of India (DCGI). 

Covovax is a Covid vaccine by the Serum Institute of India and the DGCI has recommended market authorisation for Covovax, a shift from its earlier policy of restricted use of Covovax in emergency situations. 

It first restricted the vaccine only to adults in 2021, then extended it to include the ages between 12 and 17 in 2022. It was later extended to children in the age group of seven and eleven years on June 28 last year, subject to certain conditions. On December 17, 2021, Covovax, manufactured through technology transfer from Novavax, was granted an emergency-use listing by the World Health Organization (WHO).

Way back in August 2020, US-based vaccine maker Novavax Inc. had announced a licence agreement with SII for the development and commercialization of NVX-CoV2373, its COVID-19 vaccine candidate in India and low-and-middle-income countries. Only recently, Prakash Kumar Singh, Director of government and regulatory affairs at Serum Institute of India (SII) wrote a letter to DCGI for approval of Covovax heterologous booster dose for those aged 18 years and above in view of escalating COVID-19 pandemic situation in some countries. 

Experts say Covovax has many advantages over other booster doses that are currently available in India. The first and foremost aspect is the new 'nanoparticle engulfed spike protein technology' that is used in its manufacturing. "What happens is, a spike protein is placed inside a nanoparticle and once it is injected intramuscularly inside a person, the cells come to that nanoparticle and open it up and get that internal spike protein exposed. Now when that happens, the antibodies get created inside the body and these antibodies always come with a memory of their own. So the moment there is an actual virus in the body, these antibodies will immediately start working on killing it. That's how the Covovax works," says Dr. Sanjith Saseedharan, consultant and head of critical care at SL Raheja hospital in Mumbai's Mahim.

"Covovax is not imported from any country. It is cutting-edge technology which has been put to use in the manufacturing of the vaccine right here in India. Covovax can be mixed with other doses too and in fact, when this booster dose is mixed with the other vaccines, the immunity in a person becomes much stronger. Also, Covovax is known to work against Omicron. We are definite about it and that is the reason one must opt for this as the choice for a booster dose,” Dr.Saseedharan said.

Also, in the form of a booster almost any vaccine should be okay, says Dr. T. Jacob John, virologist from CMC Vellore. "As long as your body is primed with a good vaccine which induces immunity, even a very small dose of a booster will boost the immunological system in the body. Covovax will definitely be safe because it has nothing of a microbial nature which induces inflammation in the body. In Covovax, the nanoparticle is the spike protein which means that there is nothing which induces undue inflammation in the body that both the mRNA vaccines and AstraZeneca vaccine induce because they make use of human cells to manufacture spike protein. But in Covovax, it does not make use of the human cell to make spike protein, it actually inserts the spike protein from outside and then the cells respond immunologically.

Another vaccine which will be used as a heterologous booster dose will be the indigenous nasal Covid vaccine by Bharat Biotech, but that will be for adults over eighteen years of age.