One of the things I frequently hear from parents when discussing immunizations
is a concern for the general safety of vaccines. Many parents are under
the impression that there is a lapse in safety testing protocols when
it comes to vaccines. So, let’s take a look at the process of vaccine
approval in the U.S.
Just like any other medication, vaccines go through a rigorous approval
process conducted by the Food and Drug Administration (FDA). Each new
vaccine goes through the following steps:
- Prior to any human testing, vaccines are put through a variety of safety
and efficacy tests in the laboratory, including animal testing.
- Phase 1: This is the first phase of human testing. A small study sample
is tested for major adverse reactions.
- Phase 2: A larger group of people is given the vaccine and studied further
for adverse reactions, as well as any common side effects that may arise
as a result of the vaccination. This helps establish the overall safety
of the vaccine.
- Phase 3: An even larger group of people is studied, which allows for detection
of even less common adverse events and side effects. The new vaccine is
also tested in conjunction with the other vaccines that would also be
given at the proposed interval(s) in order to make sure they are compatible.
If any problem with the vaccine is identified at any of the testing stages,
development may be stopped or delayed. After trials are complete, the
information is presented to the FDA for formal approval.
But the testing doesn’t end there. Long after a vaccine is approved,
surveillance continues using the Vaccine Adverse Event Reporting System
(VAERS). This is a passive reporting system that allows anyone to report
something that happened to them after receiving a vaccine. Reports range
from fevers to seizures to turning into the Incredible Hulk (really!).
It’s important to realize that literally anything can be reported,
which means that the data must be constantly monitored to see if patterns
develop. Further testing may be done at any point in order to support
the development and use of the vaccine (also referred to as phase 4 studies).
These testing procedures ensure vaccine safety as well as efficacy. Understanding
this process is important to being able to interpret and counter some
arguments against immunization. Given that the process may take many,
many years before a vaccine is approved and licensed, I feel quite confident
saying that they are thoroughly investigated prior to being available
to my patients.