Topic 9.2
What are the different phases of vaccine testing, and why are they important?
Developing a vaccine starts with identifying a need and progresses through extensive testing phases. This includes laboratory tests, animal studies, and human trials to ensure safety and effectiveness. Each phase builds evidence before a vaccine can be approved for public use.
Vaccine Development
How is a vaccine developed? Who decides when one is needed? How are they made?
Firstly, a need arises. A new disease emerges in the community, and the government decides a vaccine would help.
There are many experts from different organisations that help develop and test vaccines. This includes the government and independent scientists and committees.
All vaccines must be tested and evaluated to make sure they work in the way they should. Scientists want to be sure that there are no unintended problems before they are used widely.
In Australia, vaccines must go through several phases of testing in the laboratory, on animals, and then on humans before they can be approved.
Pre-Clinical Trials
Laboratory tests and animal studies are used to decide if a new vaccine protects against a disease in animals and is safe.
If it is safe and protects animals, the vaccine can progress to Phase I clinical trials in humans.
Phase I Clinical Trials
The vaccine is given to dozens of healthy volunteers who are watched closely. This phase is used to assess the right dose needed and to test for safety.
Generally, this takes at least 1 year to complete. Not all vaccine candidates pass this phase. If they do, then they progress to Phase II clinical trials.
Phase II Clinical Trials
The vaccine is given to a couple of hundred healthy volunteers.
The volunteers are watched closely for reactions (for safety). Their immune response to the vaccine is measured with regular blood tests. This is to make sure the vaccine works in the body as it should.
If the vaccine is safe, it can move into the next stage of testing in humans, Phase III clinical trials.
Phase III Clinical Trials
Thousands of people take part in Phase III clinical trials. The trial is divided into two groups – those who receive the test vaccine and those who receive a placebo or control. The participants don’t know whether they are given the vaccine or the placebo.
All participants are closely watched for safety and tested regularly. Phase III trials typically take 4-5 years to complete. With COVID-19, they were done in about a year.