How Are Vaccines Tested for Safety and Efficacy?
Vaccines are used to control disease spread by infectious organisms (germs). Hesitation by people to get vaccinated undermines this progress and reduces our ability to manage outbreaks and harm from serious disease. Therefore, it is important to answer any questions about the process for safety and efficacy testing during the U.S. Food and Drug Administration (FDA) approval process.
How are vaccines discovered?
Scientists develop vaccines to counteract how the organism causes the disease. This may be based on a similar format of a previous vaccine or a new strategy.
How are vaccines first tested?
First, animal testing is done to determine how well the vaccine works and to evaluate general safety of the product. These results are collected and submitted to the FDA along with the proposed manufacturing technology/process as an Investigational New Drug (IND) application. The FDA reviews the data and assesses whether the new product is reasonably safe for human testing.
How are subsequent tests performed and monitored?
Once the IND is reviewed and authorized by the FDA, clinical studies may begin to evaluate the vaccine under the guidance of the FDA. There are 3 phases of clinical testing:
- Phase I – A small group (20-100) healthy volunteers who have not been exposed to the disease being studied are given the vaccine. This provides initial information to show how well the vaccine works to provide an immune response.
- Phase II - If there are no safety concerns from phase I studies, various dosages are now tested in larger groups (usually 100’s of people) who may vary in health status and other characteristics. These results are compared to another similar (control) group who receive an FDA-approved vaccine or another substance.
- Phase III - Large clinical studies are conducted in large groups (1000’s of people) to provide enough data to evaluate efficacy and safety. As these studies are performed, the FDA also reviews information about the manufacturing process and facilities where the product will be produced.
When are vaccines approved by the FDA?
The FDA evaluates the data from clinical studies and the details of the manufacturing process before approval. The FDA also considers include the severity and extent of the disease being prevented, the frequency and seriousness of adverse reactions, and effectiveness of the vaccine to prevent or reduce seriousness of the disease.
Summary
The journey to create, test, and approve vaccines for use is rigorous process to determine effectiveness and safety. It takes a large team of scientists, clinicians, and experts in public health to develop a vaccine that provides safe and effective prevention of disease.