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What Is Phase I, II And III of A Clinical Trial For A Vaccine?

Published On May 19, 2021, Updated On Jul 06, 2021

If you are 18 or above, you can currently get vaccinated against COVID-19 in India. There are two vaccines that are being administered in two doses, the Covaxin by Bharat Biotech and the Covishield by Serum Institute of India. Amid concerns about the development of the vaccines and their efficacy, the vaccine drives have gone on. If you are curious about the clinical trials that the vaccines had to go through, find answers in this article.

What Is Phase I, II And III of A Clinical Trial For A Vaccine?

What Is Phase I, II and III Of Clinical Trial For A Vaccine?

Every vaccine that is to be administered to the public must go through clinical trials. These clinical trials are placed to verify whether the vaccine is safe for humans and also look at its efficacy rates. It is a graded process that is bound by strict regulations. All three phases are also reviewed by government authorities. Vaccines must pass all three phases to be allowed to be manufactured and given out to the public.

Phase I of Clinical Trial

Phase I studies are small scale studies that primarily aim to obtain preliminary information about the immune response that the vaccine will build. It monitors how the vaccine is reacting and its safety. Subsequently, the dosage and the method of administration is based on the findings. The trial is usually conducted on a small group of largely healthy patients. However, Phase I studies are open-label studies that are not randomized with placebo control groups. The individuals involved are generally chosen to be across various age and population groups so that components such as medium of administration, dosage and timings and other safety concerns can be appropriately determined. There are intensive Phase I trials involving close monitoring and extended observation as well as less intensive ones involving remote monitoring at regular intervals.

Phase II of Clinical Trial

After a vaccine passed the Phase I trial with adequate results, it moved to the Phase II trials. The Phase II trials involve a larger group of individuals who are often suffering from the condition that the vaccine is for. However, this might not always be the case. The Phase II trials aim to find how effective the vaccine is against treating the condition in an affected participant as well as preventing it in a healthy participant. The groups involved are randomized as well as more controlled. An important focus of the Phase II trials is the immune response to the antigens that will be developed by the vaccine.

Phase III of Clinical Trial

Phase III trials are often the last stage of clinical trials that a vaccine has to go through. They are performed with large populations and mainly study the efficacy rates of the vaccine as well as the safety of the immunological response that it triggers. This phase confirms the dosage levels as well as compares results with other possible forms of treatment if there are any. Phase III trials may take place over a significantly longer period of time. If the vaccine does not work on any participant at this stage, their particular data is also calculated.

Also Read: Can I Donate Plasma After COVID-19 Vaccination?

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For some vaccines, there might also be a Phase IV trial if more proof for its effectiveness is required. All vaccines must pass at least the three clinical trials to be marked as safe by the regulatory bodies. Only after that can the necessary vaccines be released into the market and administered to the people.

Disclaimer: This article is issued in the general public interest and meant for general information purposes only. Readers are advised not to rely on the contents of the article as conclusive in nature and should research further or consult an expert in this regard.

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