New Delhi: The world is hoping for a breakthrough in the multiple efforts around the global to find a vaccine to conclusively end the fight against COVID-19 pandemic that has killed more than 2 lakh people. The major problem in tackling this pandemic is that it is a new coronavirus – SARS-CoV-2, for which research had to start from scratch to understand every aspect of the pandemic.
WHO says that currently there are about 100 active projects on, to develop a vaccine for the virus. At least six of these projects, have already begun human trials by injecting formulations into volunteers in safety trials; while the rest remain in animal testing phase.
Since it is a new virus, scientists across the globe are trying different types of vaccine to find a solution. As per A report by the medical journal, Nature, there are four main types of vaccines in development, each of these have been effective in protecting against some major diseases in the past.
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Virus vaccine
The report says that there are at least seven projects that are developing vaccines using the virus itself, which is in a weakened or inactivated form. An expert from Public Health Foundation of India, explains,
Using a weakened or inactivated form of the Sars-Cov-2, will help create a long lasting immunity. Because the vaccine will be so similar to the natural infection that it help prevent the virus by creating a strong and long-lasting immune response. Just 1 or 2 doses of most virus vaccines can give you a lifetime of protection against a germ and the disease it causes.
There are many existing vaccines that have been made using this method, like measles and polio.
However, this method requires extensive safety testing, she warns.
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Viral-vector vaccines
As per the report, in this method, a virus is genetically engineered so that it can produce coronavirus proteins in the body. Since these viruses are weakened, they cannot cause the disease. This method is used in case of measles or the recently approved ebola vaccination .
The genes used in such vaccines are chemically created in labs and are either inactive or weakened. In a way that similar to the virus vaccine, these pathogens create an immune response to an infection, the expert explained.
Around 25 groups are trying to develop viral-vector vaccines against the novel coronavirus.
Nucleic-acid vaccines
At least 20 teams are aiming to use genetic instructions, in the form of DNA or RNA, for a coronavirus protein that prompts an immune response, explains the report. In this type of vaccination, the nucleic acid is inserted into human cells, which then churn out copies of the virus protein; most of these vaccines encode the virus’s spike protein, the medical expert says,
DNA and RNA based vaccines are safe and easy to develop. To produce them, only genetic material is required and not the virus itself. But it helps in stimulating both the humoral and cellular arms of the adaptive human immune system.
This type of vaccine at the moment is being used against influenza virus, hepatitis B virus and rabies.
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Protein-based vaccines
28 teams are trying protein based vaccine against COVID-19. In this method, coronavirus proteins directly injected into the body. According to the Nature report, fragments of proteins or protein shells that mimic the coronavirus’s outer coat can also be used. The first protein based vaccine was developed for Hepatitis B using this method.
[corona_data_new]These vaccines are generally not a one-shot vaccine and may require multiple doses as it needs immune-stimulating molecules along with the vaccine, she explained.
