How Coronavirus Vaccine Trials Work?
Updated On Apr 23, 2021
USA efforts and trials are in full swing to develop a Coronavirus vaccine, and drug makers are now looking for thousands of volunteers to testify the candidates for the experiment.
How Clinical Trials for the Vaccine Works?
There are three phases for vaccine clinical trials, Murphy notes, and participation in the Phase 1 trial would mean that the individual would turn out to be the first one to get an experimental vaccine.
1. Phase 1 Vaccine Trial
As per Murphy, vaccine trials for Phase 1 generally focus on safety, checking in case the vaccine trials are causing individuals to experience side effects of the vaccine. Around 10-100 healthy volunteers are recruited, who would get different doses of the COVID-19 vaccine. Commonly noticed events to a vaccine include soreness or redness at the injection site, fever, headaches, and muscle pains. In order to assess the immune response to the vaccine, blood is taken from the volunteers.
2. Phase 2 Vaccine Trial
Trials for phase 2 vaccines are similar to Phase 1 trials in consideration of the focus on immune response and adverse events. However, phase 2 trials include many healthy volunteers, who can provide a better indication of the immune and safety response in individuals, who are likely to get a vaccination in the future.
Phase 1 and Phase 2 vaccine trials include just a small portion of individuals, they just provide information regarding the side-effects of vaccines that are very rare (affecting around 10% of individuals). The efficacy of the vaccine is evaluated indirectly by measuring the levels of antibodies.
3. Phase 3 Vaccine Trial
While the Phase 3 trials can demonstrate an important finding that the vaccine not just works but is also safe to use. Such vaccine trials are controlled and conducted in the community. Through these trials, either a placebo or a vaccine is received by the individual. In case there are fewer numbers of individuals receiving the vaccine who got sick in comparison to ones who received a placebo, there is direct evidence that the vaccine helps in the prevention of disease.
During the phase 3 trial, thousands of volunteers receive the vaccine, which further gives reliable information regarding adverse events, including the ones which are rare and uncommon. Once the phase 3 trial is successful, a vaccine may be permitted for use.
Why is Placebo Required?
In order to know the functioning of vaccine works is through ‘control’, which is actually a validation of what would be the result in the absence of the vaccine. There are different risk profiles for different individuals in respect of their ages, the risky behavior they engage themselves in, and other underlying conditions. This is the reason why the trial needs to be done and scaled from around 10-1000 individuals in order to eliminate the confounding factors.
How Happens During Phase 4?
A vaccine or drug volunteer who successfully goes through Phase 3 is generally approved and licensed and the whole infrastructure of the company is dedicated to logistics and storing the drug safely without the drug losing potency or degrading. Post-market surveillance happens when the product reaches the field. It is also referred to as Phase-4, wherein all instances of product failure are kept in records.
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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.