By Dr Asmita Mahajan, Consultant Neonatologist & Pediatrician, SL Raheja Hospital, Mahim & Dr Gurudutt Bhat, Consultant Paediatrics, Fortis Hospital, Kalyan ~
Good news! Drugs Controller General of India (DCGI) cleared the first vaccine – ZyCoV-D to be administered to the adolescent population. This is a three-dose vaccine whose second and third doses are to be taken 28 and 56 days after the first. The approval has come after evaluating the interim phase III clinical trials results in consultation with the Subject Expert Committee. This is also the 1st COVID19 vaccine candidate developed on a plasmid DNA platform to be commercially introduced anywhere in the world. The governing authorities will soon take a call on its rollout. Here is what you should know.
HOW DOES THE ZYCOV-D WORK?
The vaccine is jointly developed in partnership with the Department of Biotechnology, had demonstrated a primary efficacy of 66.66% in phase 3 clinical trials. It was the first COVID19 vaccine in India to be tested in the adolescent population — those in the 12-18-yr age group. It is based on DNA-plasmid technology; then, it can be administered using a needle-free injection system; and finally, it remains stable in room temperatures for three months. Unlike mRNA vaccines, DNA-based vaccines do not require ultra-cold storage systems and are said to be more cost-effective. Zydus also claims that its technology is ideal for tackling COVID19 as it can be easily adapted to deal with mutations in the virus.
WHAT IS A DNA-PLASMID VACCINE?
Now, most active vaccines are made from a killed or weakened form of the infectious agent. A DNA-plasmid vaccine is a new approach where a piece of DNA containing the genes for the antigens is injected. The body learns to develop an immune response against the antigen, and when the pathogen attacks, the body can then generate the specific antibodies against COVID.
WHAT’S ITS EFFECTIVENESS?
To understand its effectiveness and efficacy a large clinical trial was conducted. According to the data collected during this trial, this vaccine had already exhibited robust immunogenicity, tolerability and safety profile in the adaptive Phase I/II clinical trials carried out earlier. Both the Phase 1/2 and Phase 3 clinical trials have been monitored by an independent Data Safety Monitoring Board (DSMB). It said this vaccine works against the Delta variant as the trials have been carried out in more than 50 clinical sites spread across the country, and during the peak of the second wave of COVID19, have shown the vaccine’s efficacy against the new mutant strains, especially the Delta variant. Data also shows equivalent immunogenicity with that of the three-dose regimen. Therefore, a two-dose regimen approval is also expected. However, the expert panel will review more data on the same.
SO, WHAT DOES THIS MEAN TO US?
This brings more hope for life to soon begin as usual, but as always, we can’t let our guard down. Till the maximum proportion of our population gets vaccinated and we curtail the impact of COVID to the bare minimum, we will have to continue caution. COVID-appropriate behavior will need to be followed come what may – until we win our war.
