
The vaccine reduces the risk of getting a disease by working with your body’s natural defences to build protection, therefore the sooner we reach a robust level of herd immunity, the sooner life will go back to normal. Scientist have been developing safe vaccines for decades. So, here is a quick guide on how does the testing process work.
Clinical trials must provide scientific evidence which demonstrates that the benefits of a vaccine greatly outweigh any risks.
Clinical development is a three-phase process. During Phase I, small groups of people receive the trial vaccine. In Phase II, the clinical study is expanded and the vaccine is given to people who have characteristics (such as age and physical health) similar to those for whom the new vaccine is intended. In Phase III, the vaccine is given to thousands of people and tested for efficacy and safety.
Phase 1
Phase 1 clinical trials usually include a few dozen healthy adult volunteers. They focus primarily on establishing that the vaccine is safe, and also on demonstrating that the vaccine induces an immune response.
Phase 2
Phase 2 clinical trials have hundreds of volunteers and can include specific groups for whom the new vaccine is intended. For example older adults, children or people with pre-existing medical conditions. These trials aim to test whether the vaccine causes an immune response and confirm that it is safe with minor side effects, such as a mild headache.
Phase 3
Phase 3 clinical trials include many thousands of participants. They aim to test whether a vaccine is effective in preventing people from getting the disease – in this case, COVID-19. Phase 3 trials also thoroughly assess the vaccine for safety and side effects.
In a Phase 3 trial, researchers usually compare data between vaccinated people and those who received a placebo (like a saltwater injection). They compare the frequency of infection, disease severity and any reported side effects between the two groups.
For COVID-19 vaccines, some of these phases have been combined. For example, in Phase 1 and 2 trials, results are analysed after the first few dozen volunteers are studied. The trial then proceeds in hundreds more. Some Phase 3 studies have started once preliminary data from phase 1and 2 trials are available. Having these ‘overlapping’ time frames has helped develop COVID-19 vaccines quickly, to make them available earlier to save lives.
Clinical trials rigorously tested for safety and effectiveness. The bar for vaccine safety and effectiveness is extremely high.
How a vaccine is approved for use in Australia
Before a COVID-19 vaccine is approved for use in Australia, it must pass the Therapeutic Goods Administration’s (TGA) rigorous assessment and approval processes. This includes assessment of its safety, quality and effectiveness.
The TGA is actively monitoring COVID-19 vaccine development both in Australia and around the world and is also part of a network of international regulators that meet regularly to discuss the development of COVID-19 vaccines.
The TGA is engaging early with vaccine developers, undertaking a thorough and efficient review of vaccine candidates and discussing the application process. Early engagement will not affect the comprehensive review process that clinical trial results are subject to in Australia.
Multiple vaccines may be approved in a country. Some vaccines may be approved for specific people first. A health care professional can help ensure that you get the right vaccine for you.
After every vaccine has been approved, scientists continue to monitor its safety.
By Joe Cusmano