Covid-19 is still spreading at an unprecedented rate. Scientists all around the world are working day and night to develop a vaccine for it.
- The vaccine candidate was found to be safe and immunogenic in clinical trials.
- Antibodies produced after injection was able to completely neutralize the virus.
- ZyCoV-D uses a non-replicative and non-integrative plasmid.
- Human clinical trials will start in July 2020
While a drug for the cure or treatment of a disease is only given to sick or unhealthy people, the vaccine, however, is meant for everyone from each age group and gender, which means healthy people will be exposed to the vaccine. Thus, the utmost safety and effectiveness of the vaccine candidate have to be evaluated before it could be made for public use.
Zydus’s Vaccine candidate ZyCoV-D
One of India’s leading pharmaceutical company Zydus Cadila’s vaccine candidate ZyCoV-D got approval from the Drug Controller General of India – Central Drugs Standard Control Organisation (DCGI-CDSCO) on 2nd July 2020 to initiate Phase I/II human clinical trials in India. It was the second Covid-19 vaccine candidate in India after Bharat Biotech’s Covaxin to get approved for human clinical trials.
The company plans to initiate human clinical trials on over 1000 subjects in July across the country(India).
The vaccine was found to be safe and effective in pre-clinical studies done on mice, rats, guinea pigs, and rabbits. The vaccine candidate was found to be immunogenic and resulted in a strong immune response in these animals. Antibodies produced as a result of vaccine injection were able to neutralize the wild-type (original/non-mutated) virus in the virus neutralization assay.
More about ZyCoV-D
The vaccine candidate uses a non-integrative and non-replicative plasmid, meaning it would not integrate with the host cell’s genome and it would not multiply or divide.
The vaccine candidate was found to be safe in repeat dose toxicology studies by both intramuscular and intradermal routes of administration. In rabbits, up to three times the average human dose was found to be safe and immunogenic(activates immune system). The vaccine candidate is safe and requires minimum biosafety requirements lab (BSL-1). It is stable and can be transported easily. If in case the virus mutates, the vaccine candidate could be easily modified since it’s a plasmid.
What are plasmids?
Plasmids are extra-chromosomal self-replicating small circular DNA generally found in some bacteria which confers different functions such as in defense, antibiotic resistance, toxicity etc. Further, these plasmids are of different types based on their function.
Using the application of recombination DNA technology, these plasmids could be used in different ways such as vectors in gene therapy, vaccine, metabolites production, etc.
How it will provide immunity?
The plasmid is incorporated with genes of interest (virus genome components), which is meant to confer immunity to an individual once injected. After injection, it activates the immune system, further causing specific antibodies to proliferate and divide against it.