Unlike drugs, which are used to treat sick people, vaccines are
used in healthy people to prevent certain illnesses. Before a
vaccine can be used in the United States, it must be shown to be
safe and effective. To make these determinations, the U.S. Food
and Drug Administration (FDA) conducts a rigorous review of data
regarding the vaccine’s safety and efficacy. Because healthy
children are typically the recipients of vaccines, safety
requirements are especially stringent. Many federal agencies and
private organizations are involved in ensuring the safety of
vaccines and for promoting the health of the population: The FDA
regulates vaccines that are used in the United States, ensuring
that they are shown to be safe and effective before they are
approved for use. The vaccine first undergoes laboratory
studies, then studies with animals, and then with humans. The
results of the studies at every step in the process must show
that the vaccine does what it is supposed to do, and that it
does not harm people who re