Good news! The 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 and the 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 COVID-19 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.
TC46 connected with Neonatologist & Pediatrician Dr Asmita Mahajan of SL Raheja Hospital, Mumbai & Pediatrician Dr Gurudutt Bhat of Fortis Hospital, Mumbai to highlight important facts about this new vaccine. Here they share its efficacy, how it works, advantages and drawbacks and more.
1. The first Covid-19 vaccine in India to be tested in the adolescent population
Dr Mahajan and Dr Bhat explain that, “The vaccine is jointly developed in partnership with the Department of Biotechnology, and has demonstrated a primary efficacy of 66.66% in phase 3 clinical trials. It was the first COVID-19 vaccine in India to be tested in the adolescent population — those in the 12-18-year 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 COVID-19 as it can be easily adapted to deal with mutations in the virus.”
2. A DNA-plasmid vaccine is a new approach
Dr Mahajan explains, “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-19.”
3. DNA vaccines have a stronger ability to generate more antibodies
Dr Bhat says, “One of the main advantages of a DNA vaccine is that it can stimulate both the humoral (also known as antibody-mediated immunity) and cellular arms (response associated with the activation of Phagocytes, Cytokines in response to antigen without involving antibodies) of the adaptive immune system. DNA vaccines have a stronger ability to generate more antibodies B Lymphocytes against the harmful pathogens infiltrating the body. Another highly beneficial aspect of DNA vaccines is that they can be very versatile. They can be used to treat genetic disorders, malignancies, etc. The few drawbacks of a DNA-based vaccine are that they are limited to protein immunogens and can generate antibody production against DNA.”
4. In all its three phases of trials, the vaccine has shown safety for 12-18 years age group
Dr Bhat states, “The ZyCoV-D vaccine is currently the first plasmid DNA vaccine in the world. In this DNA vaccine, the part which enables the COVID-19 virus to enter human cells, causing the disease, is coded. Thereby, when the vaccine is introduced into the body, the same part of the virus is produced, prompting the body’s immune system to generate antibodies. Like mRNA vaccines, the DNA one is also lab-made; hence, it cannot intrude or disrupt a human’s genetic composition. In all its three phases of trials, the vaccine has shown safety in every age group, including 12-18years.”
5. The vaccine will be administered without needles
Dr Bhat explains that “As per records, the vaccine will be administered without needles using a painless device known as Pharmajet or jet inject. It will be a three-dose vaccine, each dose having 2mg, which will be split into two parts then introduced at two different sites. The purpose of it is to increase the immune response.”
6. Vaccine rollout to begin between mid-September to October
There is no exact information on the price of the vaccine yet. However, the rollout of the vaccine is stated to begin somewhere between mid-September to October.
7. Trials have shown the vaccine’s efficacy against the new mutant strains
Dr Mahajan and Dr Bhat highlight, “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 COVID-19, 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.”
8. COVID-appropriate behaviour will need to be followed
Dr Mahajan and Dr Bhat say that “This brings more hope for life to soon begin as usual, but as always, we can’t let our guard down. Until 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 behaviour will need to be followed come what may – until we win our war.”
9. Vaccine will be upgraded if needed to fight off more infectious strains
“According to data, the majority of the vaccine trials were during the second wave involving the peak. In April, May, June, 99% of the cases were of the Delta variant as per information available in the public domain. The company has mentioned that they would upgrade the vaccine if needed to fight off more infectious strains. They are currently studying the vaccine’s effectiveness against the different variants”, shares Dr Bhat.
