New Delhi: The whole world has been biting the corona since the beginning of last year. According to experts, the only way to get rid of this deadly virus is a vaccine. And so every country in the world has become desperate to make and take this vaccine. But creating and spreading this vaccine is a long process, where success is quite limited. It takes an average of about 10 years to make a new vaccine. In many cases it may take longer. Even during pre-clinical and clinical trials, less than 10 percent of vaccines are successful.
Unprecedented competition has been observed around the world in the development of the corona vaccine. More than 300 vaccines have already entered the pre-clinical and clinical trial stages. Less than a year after the outbreak of SARS-CoV-2, the first Covid-19 vaccine, Pfizer-BioNTech, was approved for Emergency Use Authorization in the UK on 2 December 2020. Since then, many countries have approved more emergency vaccines for emergency use.
Vaccines made in India and used platforms
Two Covid-19 vaccines are currently being used in India. Covishield, a joint venture between Oxford University and the British Swedish organization AstraZeneca. It is based on a viral-vector platform. And the other is Covaxin, a joint venture between India Biotech and the Indian Council of Medical Research. This is an inactive vaccine. The third vaccine is Sputnik V (Gamalia Research Institute in Russia). Which is already licensed and is going to be made in India very soon. It is also based on the viral-vector platform. Let us know in detail about these two platforms.
Viral-vectored vaccines: Some vaccines introduce genetic material into cells using harmless viruses or bacteria as vectors or carriers and build up immunity against it. Once the viral vector enters our cells, the genetic material instructs the cells to make a protein. It stimulates the production of T-lymphocytes and B-lymphocytes in our body which gives us strength to fight this virus in the future. An example of a viral vector vaccine is the ‘RVSV-ZEBOV’ vaccine against Ebola.
Inactivated or killed vaccines: Pathogens (viruses or bacteria) that cannot be multiplied cannot cause disease. So neutralizing any viruses or bacteria, using chemicals like formalin, can convert them into safe immunogenesis. Since inactivated viruses or bacteria do not multiply, we need to use multiple doses of the vaccine and be given one more ingredient to improve the immune response – this is called adjuvant. In China and India, Covaxin is an inactive platform for making several vaccines.
There are also several other types of vaccines:
RNA vaccine: In this case, the messenger carries the genetic sequence for the RNA (mRNA) protein (the spike protein of SARS-COV-2) is usually bound to fatty nanoparticles. It is similar to the cell membrane and can supply RNA to the host cell. To make spike proteins, the cell uses its protein-producing apparatus, which is then released from the host cell and recognized by the immune system, causing a reaction that results in both antibody production and cellular immunity. Protein Subunit Vaccines: A vaccine that is made up entirely or in part of a protein is called a protein or subunit vaccine. Many subunits or protein vaccines are produced in bacterial or fungal cells, so that large amounts of protein can be easily produced. Many companies are working on a protein vaccine based on the spike protein of SARS-CoV-2. Some, depending on the size of the protein, will need an assistant. Creating a larger protein related to the protein vaccine that binds itself to particles like the whole virus is a method previously used for the human papilloma virus (HPV) vaccine.
DNA vaccines: These vaccines are similar to the RNA vaccines in carrying out the sequence of gene codes for proteins. Which properly induces the immune system. However, the process of this vaccine is somewhat more complex than that of mRNA vaccines. The Zydus Cadila vaccine in India uses a DNA plasmid. Vaccines are being developed based on this method.