If you can remember getting immunized against measles or chickenpox as a youngster or even if you get a flu shot every winter, you may have wondered how the vaccines were developed in the first place. Of course, vaccine approval is an incredibly long and detailed process closely monitored by the U.S. Food and Drug Administration. In fact, it’s not unusual for a new vaccine formulation to withstand well over ten years of research and testing before it’s finally approved for full-scale use. So how does it go from a researcher’s idea to the Center for Disease Control’s recommended immunization list?
Where Does a Vaccine Start?
In its beginnings, a potential new formula is in what’s known as the exploratory stage. Two to four years of lab work testing and research will go into if it’s possible and how best to attack a particular disease with a vaccine. There are a few different ways to do this, including actually utilizing a part of the virus to create the counteragent. For instance, both the HPV and the Hepatitis B vaccines are created this way.
Next comes the one to two-year long pre-clinical stage. This is where researchers use tissue and cell studies and animal testing to pin down what the formulation may do in human test subjects. If the testing shows no promising immunity response the drug goes back to the drawing board, or possibly even shelved for good.
Once a research team achieves the results they’re looking for in the pre-clinical stage, the vaccine can finally move into the first of three separate phases of human trials which consists of anywhere from a couple of dozen up to around eighty adults. If it’s a children’s immunization the test subject age range will steadily drop over the course of the trial until finally reaching the desired age range. Two more trials stages await any vaccine making it out of phase one, each with progressively larger and larger test groups. For example, phase two may be several hundred people and phase three could be fifty thousand people, each with restrictions and guidelines intended to provide the highest quality, most effective, and safest product possible.
And Still More Research And Testing ...
After three successful phases of human trials comes more rounds of licensing, approvals, inspections, and even some additional testing (known as phase four trials) to evaluate and monitor the vaccine even further. With all of the studies and research required for a single formula it’s easier to understand why it takes over a decade to develop a new vaccine and introduce it safely to the public.