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How Vaccines Work


Vaccines help us protect ourselves by making us immune to pathogens. A pathogen is another word for germs — it is something that makes us sick, like bacteria or a virus.

One way our bodies develop immunity to pathogens is by creating antibodies. Antibodies act as protein warriors that detect foreign pathogens inside of the body. When these antibodies detect pathogens that could potentially harm us, they signal the “special ops” to destroy them. Vaccines introduce us to a weakened form of a specific pathogen, which helps our bodies learn to produce the specific antibodies that may be needed to fight it in the future.

What's in a Vaccine


Herd Immunity


Herd immunity is a type of protection from infectious disease, which occurs once a high enough percentage of the population has become immune. With herd immunity, individuals without immunity to the disease are less likely to be exposed to it. Herd immunity is why it is so important to get vaccination rates up and keep them up — by maintaining high levels of immunity, we can prevent infectious diseases from being spread in our community.

Vaccines' Global Impact


Smallpox was declared eradicated from the world in the 1970s — a feat that would not have been possible without vaccination.

Thanks to the smallpox vaccine, scientists estimate that around 150-200 million lives have been saved since its eradication. It is important to note that smallpox was NOT eradicated as soon as an effective smallpox vaccine was readily available, but rather when the public decided that it was their civic duty to protect themselves and their loved ones by vaccination. Vaccines don’t save lives; vaccinations do.

“A vaccine that remains in the vial is 0% effective, even if it is the best vaccine in the world.”

More Resources

Why do we need vaccines?


Vaccine Science: Vaccines and the Immune System:

Vaccine Basics | Frequently Asked Questions

Clear Answers and Smart Advice About Your Baby’s Shots

Childhood Vaccines: Tough Questions, Straight Answers

Where can I learn more?


Reliable Sources of Immunization Information

How can I know my sources are trustworthy?