The country’s first messenger RNA, or mRNA, vaccine, is prepping for launch with the Pune-based Gennova Biopharmaceuticals on course with its human trials, reports say, adding that a variant-specific version is also in the works to tackle the Omicron variant. Amid the pandemic, mRNA vaccines have reported a strong ability to impart protection against the novel coronavirus and two notable candidates — created by Pfizer-BioNTech and Moderna — are the mainstays of the vaccination drive of several advanced nations.
What Is The Gennova Vaccine?
Emcure Pharmaceuticals says that Gennova, its subsidiary, is “India’s only company to deploy the mRNA platform to develop a vaccine" against the novel coronavirus.
It has developed its candidate, known as HGC019, in collaboration with the US-based HDT Biotech Corporation, starting work on the vaccine right after the Sars-CoV-2 genome was published in January 2020.
It was reported in August 2021 that India had okayed further human trials of the Gennova vaccine after the shot was found to be safe and effective in initial studies, demonstrating “safety, immunogenicity and neutralisation antibody activity in rodents and non-human primate models". Clinical trials are partly funded by India’s Ministry of Science and Technology, reports said.
The Times Of India said Gennova has submitted Phase-II trial data of its two-dose vaccine, which was developed to target the Delta variant, and is also working on a version of the jab against the Omicron variant.
What Is An mRNA Vaccine?
These vaccines belong to the category of nucleic acid vaccines, which use genetic material from a disease-causing virus or pathogen to trigger an immune response against it within the body.
All vaccines seek to expose the body to the active part of the pathogen that enables it to infect humans so that the immune system recognises it and produces antibodies against it in the future. How traditional vaccines achieve this is by inserting a part of the virus itself — either weakened or inactivated — into the body.
But what nucleic acid vaccines, like DNA or RNA vaccines, do is to insert the genetic code of the pathogen into the body to prompt the human cells themselves to produce the target proteins for the immune system to identify and attack. India has already authorised the world’s first DNA vaccine — ZyCoV-D, created by the Ahmedabad-based Zydus Cadila — for induction into its homegrown Covid-19 vaccine arsenal though it is yet to be rolled out as part of the vaccination campaign.
Since such vaccines do not use any live components of the virus, they are seen as posing no risk of actually triggering the disease. But this approach to creating vaccine is “relatively new" and while DNA and RNA vaccines are being developed against various diseases, including HIV, Zika virus, it is with Covid-19 that the first such vaccines have been authorised for human use after they received emergency clearance from drugs regulators.
Emcure said that HGC019 has “all the necessary information to guide the host cells to make the antigen — spike protein of the virus" and, upon being injected into the body “instructs the cells to make numerous copies of the mRNA and antigen". Other immune cells also act on the spike proteins, thus learning to “identify the coronavirus and protect the body if the person were ever to be actually infected".
What Are The Advantages Of mRNA Vaccines?
Experts say that mRNA vaccines are well-poised for keeping up with continual changes displayed by a rapidly evolving virus like Sars-CoV-2 because they can be tweaked with relative ease to target new variants as the key factor is to have sequenced the genome of the target pathogen.
A scientist who worked on the Moderna vaccine has referred to mRNA vaccines as employing a “plug and play" approach whereby they lend themselves to easy upgrades through the replacing of “one sequence of mRNA in the vaccine for another in a matter of weeks", allowing pharma companies to create and test vaccines to target newer novel coronavirus variants. Of course, the newer versions are also subject to trials, but not of the scale required by the initial shots.
Emcure points out, “mRNA vaccines are… the ideal choice given their rapid developmental timeline". These vaccines are “fully synthetic and do not require a host for growth, example eggs or bacteria", it says, adding that “therefore, they have a shorter manufacturing lead time". The Moderna mRNA vaccine had gone into clinical trials within two months of the SARS-CoV-2 genome being sequenced.
Further, HGCO19 uses the “self-amplifying mRNA platform which gives it the advantage of a low dosing regimen", Emcure says, noting that its vaccine is stable at 2-8 degrees Celsius. That would mean it would meet the logistical requirements for storage and transportation in India.
The self-amplifying, or saRNA platform, makes the Gennova shot slightly different from the likes of the Pfizer and Moderna vaccines. While both mRNA and saRNA vaccines work primarily by carrying the instruction, or message, to the human cells to produce the key protein of the target pathogen, an saRNA vaccine “also contains the code for the virus enzyme", which enables it to “create multiple copies of the virus RNA once it’s in our cells, leading to quicker protein production".
Since an saRNA vaccine can produce copies of itself inside a cell, “lower doses are required than those for mRNA vaccines".
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