Akash Pramamik,D.Y Patil Medical College, Kolhapur
The past experiences have shown that the development of a vaccine is a long process and studies are done in sequential steps. Due to the recent outbreak of the coronavirus pandemic, the government along with the pharmaceutical companies are gearing up to develop a vaccine as soon as possible. The process of development involves various stages and steps. According to the World Health Organization (WHO), there are 6 stages of vaccine development which are as follows:
1. Exploratory Stage, 2. Pre-clinical, 3.Clinical Development, 4.Regulatory Review, and Approval, 5.Manufacturing, 6.Quality control
The clinical-stage of development further involves four phases.
Stages of vaccine development
1. Exploratory Stage
In this stage, the scientists identify natural or synthetic antigens in the laboratory that might help to prevent or treat a disease. These antigens could include virus-like particles, weakened viruses or bacteria, weakened bacterial toxins, or other substances derived from other pathogens. There may also be the addition of some specialized molecules which are known as adjuvants that can promote the body’s immune response. This stage lasts up to 2-4 years.
2. Pre-clinical stage
So once a vaccine candidate has been identified from the Exploratory Stage, it’s time for the preclinical stage where the vaccines are tested in culture and in animal models. These animal models are carefully selected based on whether a given animal gets sick in a similar way to humans to be scientifically informative. Animal subjects may include mice, monkeys, hamsters, Rhesus macaques, and fee rats.
This study gives an idea of cellular responses that they might expect in humans. This stage usually lasts for 1-2 years and usually involves research from private industries.
3. Clinical Development : This stage is further divided into four phases.
a) Phase I Clinical Trials
Phase I human trials are done with groups of fewer than a hundred volunteers (20-80 normally). The goal in this stage is to find out the type and extent of the immune response generated by the vaccine candidate in humans. These trials both tests to see whether there are any serious or significant side effects and also used to establish a safe dose for vaccine though bigger trials will provide more feedback there as well.
b) Phase II Clinical Trials
This stage involves several hundreds of volunteers where some individuals may also belong to the high-risk group. These trials are randomized and with a control group that gets a placebo. Here researchers can study more about vaccine safety, the right dose, and how those doses have to be timed out.
C) Phase III clinical trials
This phase involves randomized and double-blinded testing in groups of thousands of volunteers. The goal of phase 3 trials is to find out how effective the vaccine will actually be. It also helps us to find out vaccine safety in a large population and also to rule out rare side effects that are not seen in a small population.
d) Phase IV Clinical Trials
Some manufacturers may also opt for Phase IV trials after the vaccine has been released. During this phase, they may continue to test for vaccine safety, efficacy, and other potential uses.
4. Regulatory Review and Approval
Once the vaccine clears all the above stages the vaccine developer submits a license application to the regulatory authority which contains data and information collected from the development to the trials of the new vaccine.
Normally the approval can be accelerated if there were a similar vaccine approved in the past. Also, during a pandemic, a vaccine may get “emergency use authorization” before getting formally approved.
5. Manufacturing process
Once the vaccine is approved the manufacturer provide personnel, infrastructure, and equipment so that they can create mass quantities of vaccine.
6. Quality Control
The entire process of manufacturing requires stringent quality control measures. The quality control measures are taken to monitor the safety, performance, and effectiveness of an approved vaccine.
Along the way, if any of these vaccine “candidates” are shown to be unsafe or ineffective, researchers must return to the laboratory to develop a new candidate. This is why vaccine development can be a long and uncertain process.
Conclusion:
So, as we could already see that time itself is a necessary part of the process but the good news is for the Covid-19 vaccine this process is being accelerated at an unprecedented level. Even with this accelerated pace, it takes time to find the correct dose to make sure the vaccine will work and be safe enough for the people. Also, we need to prioritize the distribution of the vaccine to the most vulnerable section of society first. So lots of thought process and work is to be required for production and distribution too.
So we hope a vaccine would be available in the market as soon as possible and the necessary is being done. Till then we should be maintaining social distancing, wear the mask, and do frequent hand washing.
Also read: iGenomics: An open-source application for DNA sequencing
Reference:
1.https://www.historyofvaccines.org/content/articles/vaccine-development-testing-and-regulation
2. https://www.cdc.gov/vaccines/basics/test-approve.htm
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