We have all heard a lot about vaccines, but not many of us know how they are being developed and tested. In the United States, vaccine development and testing have a standard set of steps to follow, which include laboratory studies, clinical studies with humans, final approval.

First step: Laboratory Studies

At first, scientists need to gather all the necessary information about a disease to start making a vaccine. This is known as the “exploratory stage”, which includes basic laboratory research and can last up to 4 years. This stage is usually funded by the government. However, some private companies may help, too, which can significantly reduce the amount of time spent on research.

Once the required information has been gathered and studied, the “pre-clinical stage” starts. Scientists begin testing the safety and side effects of a vaccine on animals, such as mice or monkeys. These trials give researchers an idea of a safe starting dose for a vaccine and the bodily responses they might expect to see in humans.

The testing can take up to 2 years. Once it’s over, the vaccine will undergo three clinical phases.

Second step: Clinical Development

Phase 1: The first attempt to test the vaccine involves a small group of adults. They receive a trial vaccine that will determine its safety and the immune response it triggers.

Phase 2: A larger group of adults will be tested during this stage. They might include people who have risk factors for getting the disease, such as age or some physical conditions. These trials also include a placebo group. A placebo group is a group of people who receive treatment that does not have a real effect.
The testing here determines the vaccine’s safety, its delivery method, and people’s immune responses.

Phase 3: Thousands of people receive the vaccine during this trial. This phase shows the possible side effects of the vaccine and tests its safety and efficacy.

Third step: Approval

After a successful Phase 3 trial, the vaccine gets a license. Vaccine production is closely monitored and involves a lot of safety tests before going on the pharmacy shelves.

There is an optional Phase 4 trial of the vaccine where the manufacturer continues to test the safety and efficacy of the vaccine during its production.

Overall, vaccine development is thoroughly controlled and tested to ensure its safe usage for large groups of people.