Vaccines work. 

Vaccines save lives.

Vaccine Facts: 

Why You and your Family Need Vaccines 

From babies to adults, people

need vaccines to protect them 

from potentially dangerous 

infectious diseases. Without 

vaccines, children and adults 

are at risk for serious illness 

and even death from vaccinepreventable diseases. 

Ensuring the safety and

effectiveness of vaccines 

used in the U.S. is one of the 

FDA’s top priorities. Here 

are the facts on vaccines 

for you and your family. 

The FDA has oversight

of the safety, 

effectiveness and 

quality of vaccines

used in the U.S. 

Vaccines to prevent 

infectious diseases 

are given to millions

of babies, children, 

adolescents and adults, and 

it is critical that they meet the

FDA’s safety and effectiveness

standards. Vaccines have 

prevented countless cases of 

disease and disability and have

saved millions of lives. 

Vaccines work. 

Because immunization 

programs of the 20th and

21st centuries have been so 

successful, many people today

have never seen the various 

vaccine-preventable diseases 

that were once common, 

including polio, diphtheria,

rubella (German measles), and

chickenpox. 

Vaccines save lives. 

Infectious diseases that 

once killed or harmed many

infants, children and adults 

Vaccine Facts: Why You and your Family Need Vaccines, Pg. 1 
Vaccination helps protect 

communities. 

Most side effects from 

vaccines are mild.

The FDA’s evaluation to 

determine the safety and 

effectiveness of vaccines is 

among the most robust in the 

world.

Vaccines work by mimicking the 

infectious bacteria or viruses that 

cause disease.

There are real dangers for 

the health of kids who are 

unvaccinated.

could reemerge if people aren’t 

vaccinated. The germs (viruses

and bacteria) that cause vaccinepreventable diseases still exist 

and can harm people who are not 

vaccinated. 

Vaccination helps protect 

communities. 

If too many individuals choose

not to vaccinate themselves or 

their children, some diseases 

that are now rare or nonexistent 

in the U.S. may resurface. For 

example, measles is one of the

most contagious respiratory

diseases in the world and 

has the potential to be lifethreatening for some people.

Outbreaks in the U.S. continue 

to occur because measles is 

common in many parts of the

world, unvaccinated travelers 

with measles are bringing the

disease into the U.S. from other 

countries, and measles can 

spread in communities in the 

U.S. where groups of people are 

unvaccinated. 

Most side effects from 

vaccines are mild. 

A vaccine is a medical product. 

Like any medicine, vaccines can 

cause side effects. But most are 

minor and short-lived, such as 

a low-grade fever, or pain and 

redness at the injection site.

Vaccines are safe and severe 

side effects are rare. The risk 

of being harmed by vaccines is

much smaller than the risk of 

serious illness from the diseases 

they prevent. Let your health care 

professional know about any

questions or concerns you have

about vaccines. 

The FDA’s evaluation to 

determine the safety and

effectiveness of vaccines is 

among the most robust in the 

world. 

Vaccine studies are carefully

designed to evaluate safety and

effectiveness, keeping in mind

that millions of people may 

receive the vaccine. Vaccines 

don’t make you sick with the

disease they are preventing.

When determining whether to 

approve or authorize a vaccine 

for emergency use, the FDA bases its

decisions on its analysis of the benefits

and risks for the intended population

who will receive the vaccine. 

Vaccines work by mimicking the

infectious bacteria or viruses that 

cause disease. 

Vaccination stimulates the body’s 

immune system to build up defenses

against the infectious bacteria or virus

without causing the disease. After

vaccination, the immune system is

better prepared to respond quickly and

forcefully when the body comes across 

the real disease-causing organism. 

There are real dangers for

the health of kids who are 

unvaccinated. 

Some people are surprised to

learn that children can be harmed

by or even die of measles,

influenza and other diseases that 

can be prevented by vaccines. 

Learn the facts about the benefits 

and risks of vaccines, along with

the potential consequences of not

vaccinating against infectious diseases. 

• Vaccines Protect Children From 

Harmful Infectious Diseases | FDA 

• Vaccination Is the Best Protection 

Against Measles | FDA 

• Vaccines for Children - A Guide for 

Parents and Caregivers | FDA 

• Questions about Vaccines | FDA 

• Vaccine Development-101 | FDA 

Vaccine Facts: Why You and your Family Need Vaccines, Pg. 2