According to the details about the trial that have been reported thus far, the participants will receive two intramuscular injections about 28 days apart. Not everyone will receive the vaccine injection. Participants will be randomly assigned to either receive either two 6-microgram injections of Covaxin or two shots of a placebo.
What is a placebo in a vaccine trial?
A placebo is used in clinical trials to test the effectiveness of treatments and is most often used in drug studies. For instance, people in one group get the tested drug, while the others receive a fake drug, or placebo, that they think is the real thing.
Placebos have been essential to clinical trials for decades. It’s vital that neither the volunteers nor the staff running the trial know who is randomly assigned to get the vaccine or the placebo. This “blinding,” as it’s called, eliminates the chance that people will behave differently depending on which treatment they get, potentially skewing the trial’s results.
In some COVID-19 vaccine trials, participants in the control group (the group receiving a placebo) are injected with a saline solution. In other trials, they receive an actual treatment. For example, in the COVID-19 vaccine developed by the University of Oxford, the control group receives a meningitis and septicaemia vaccine as a placebo.
The benefit of using an actual vaccine as the placebo control is that it will cause a similar reaction at the site of the injection as the COVID-19 vaccine, such as muscle pain and soreness.
Covaxin is being developed indigenously by Bharat Biotech in collaboration with the Indian Council of Medical Research (ICMR). Bharat Biotech is expected to release a scientific response on the development later on Saturday. Covaxin is still a vaccine candidate and even if a vaccine is rolled out in India, the vaccine may not mean you are immune from getting infected by the coronavirus, and so citizens will need to keep taking precautions like physical distancing, washing hands, and wearing masks.