Are vaccines an effective tool to prevent disease?

Vaccines are a proven way to prevent disease — I'll gather the latest evidence on how well they work.

Yes, vaccines are one of the most effective tools to prevent disease.

Evidence is based on decades of scientific research:

> decades of scientific research confirming that vaccines are one of the most effective tools for preventing serious diseases
> Vaccines are the safest and most effective way to prevent the spread of infectious diseases, including measles, whooping cough and polio

> Vaccines have been one of the most effective tools in preventing infectious diseases for over a century

> Vaccinations are one of the most impactful public health interventions, saving millions of lives annually and reducing the spread of infectious diseases

> Vaccination is one of the most effective ways to prevent diseases

How vaccines prevent disease

Vaccines work by training the immune system:

> According to the Centers for Disease Control and Prevention (CDC), vaccines train the immune system to recognize and fight pathogens efficiently, leading to long-lasting immunity and reduced disease severity

High effectiveness for individual vaccines:

•Measles vaccines achieve up to 95% efficacy after two doses, while polio vaccines provide near-complete protection through multiple doses

•Most childhood vaccines are over 90% effective at protecting against disease

•For COVID-19, effectiveness is not absolute prevention of infection but measurable reduction in severe outcomes — many studies emphasize strong protection, especially against hospitalization and critical illness in older adults

We now have vaccines to prevent more than 30 life-threatening diseases

Community protection through herd immunity:

> When more people are vaccinated in a community, the spread of the disease slows down, as fewer people can carry and transmit the disease. This is known as herd immunity

Measured impact at population level

Global impact:

•Immunization currently prevents 3.5 million to 5 million deaths every year from diseases like diphtheria, tetanus, pertussis (whooping cough), influenza and measles

•Vaccines prevent an estimated more than 4 million deaths worldwide every year

•Vaccines have saved an estimated 154 million lives globally over 50 years, eliminated smallpox from the planet, and reduced diseases like polio and measles by over 99% in the United States

•Also estimated: Vaccines have saved an estimated 154 million lives globally over 50 years, eliminated smallpox

•Over the past 50 years, essential vaccines against just 14 diseases have saved at least 154 million lives and during the same period, vaccination has contributed to 40% of the drop in infant deaths

United States impact:

•The CDC estimates that vaccines given to children born between 1994 and 2018 will prevent approximately 419 million illnesses and 936,000 deaths over their lifetimes

•Vaccines prevented more than 500 million illnesses and 1.13 million deaths among children born over the last three decades

Historical eradication and control:

•One of the most successful CDC immunizations is the vaccine for smallpox, which was eradicated worldwide in 1977 due to widespread vaccination efforts

Vaccines are very effective but not 100% guaranteed to prevent illness in every person — they can provide high levels of protectionand require high coverage to maintain herd immunity for highly contagious diseases like measles.

Citations (2)

1aap.orgNonprofits and think tanks
Fact Checked: Immunizations Are Essential for Public Health and Child Safety
Backs: “Yes, vaccines are one of the most effective tools to prevent disease. Evidence is based on decades of scientific research: decades of scientific research confirming that vaccines are one of the most effective tools for preventing serious diseases”
2senate.govGovernment
The Evidence Base for Vaccine Safety and Efficacy
Backs: “Vaccines have saved an estimated 154 million lives globally over 50 years, eliminated smallpox from the planet, and reduced diseases like polio and measles by over 99% in the United States. Also estimated: Vaccines have saved an estimated 154 million lives globally over 50 years, eliminated smallpox”