Coronavirus vaccine: First, it has been identified that the SARS-CoV-2 virus behind the COVID-19 does not replicate in such eggs. Second, the egg-driven technology also takes more time
Coronavirus has thrown a challenge before the human intelligence and a prompt, as well as effective retaliation, must come in the form of COVID-19 vaccine. While it takes years of research and testing to produce a vaccine, scientists are coming up with new methods in order to expedite the development process of COVID-19 vaccine. Indian firms such as Serum Institute of India (SII), Bharat Biotech, and Zydus Cadila are also upgrading process to produce a safe and effective vaccine. Around the world, researchers are working on more than 165 potential Coronavirus vaccines, out of which around 27 have managed to reach the different stages of human trials. The experimental vaccine of the University of Oxford and AstraZeneca are among the five potential candidates that have entered Phase III of human clinical trials. Serum, which has tied up with Oxford-AstraZeneca to mass-produce the potential vaccine COVISHIELD in India, has received approval from the Drugs Controller General of India to conduct Phase II and III human clinical trials in the country.
During the swine flu (H1N1) pandemic, Serum was asked to develop a vaccine. It had adopted a 70-year-old technique of injecting a flu virus into a fertilised hen’s egg. Subsequently, the egg acts as hot helping the growth of the virus and replicated virus is developed. Researchers then purify the fluid from the egg to get the replicated virus. After that this replicated virus is either killed or passed through more eggs based on the type of vaccine candidate. Around 90 per cent of yellow fever, measles, mumps, and influenza vaccines can be made from technology based on pathogen-free chicken egg, Chennai-based oncologist and vaccine specialist Anita Ramesh was quoted as saying by The Indian Express.
However, the demand to develop a vaccine as early as possible has sidelined the traditional technology. There are two main reasons. First, it has been identified that the SARS-CoV-2 virus behind the COVID-19 does not replicate in such eggs. Second, the egg-driven technology also takes more time, The Indian Express report said.
During the COVID-19 pandemic, most of us have become familiar with terms like DNA, mRNA based vaccine candidate. For example, Oxford-AstraZeneca’s Coronavirus candidate is DNA-based while Moderna’s is mRNA-based. There are two advantages of DNA and mRNA driven technologies. DNA and mRNA vaccines are chemically synthesized as these types of candidates don’t require the virus to be replicated. Researchers need to target the code for the most crucial part that the body’s immune system. Secondly, these viruses can be manufactured at a large scale through bioreactors, the IE report said. Ahmedabad-based Zydus Cadila has been working on a DNA plasmid vaccine on humans. COVAXIN co-maker Bharat Biotech is testing an inactivated virus. Apart from this, the firm has also been working non-replicating and replicating viral vectors.
These modern technologies are easier and faster than egg technology but they are expensive too, The Indian Express report said.