Are vaccines an effective tool to prevent disease?

Vaccines prevent disease — I'll pull the latest evidence on how well they work.

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

Scientific and public health evidence from leading health organizations shows:

> Vaccination is one of the most effective ways to prevent diseases. Over the past 50 years, essential vaccines against just 14 diseases have saved at least 154 million lives

> We now have vaccines to prevent more than 30 life-threatening diseases and infections, helping people of all ages live longer, healthier lives. Immunization currently prevents 3.5 million to 5 million deaths every year from diseases like diphtheria, tetanus, pertussis (whooping cough), influenza and measles

> Immunization is a global health success story, saving millions of lives every year. Vaccines reduce risks of getting a disease by working with your body’s natural defenses to build protection. When you get a vaccine, your immune system responds

How they work:
Vaccines train your immune system to create antibodies, just as it does when it’s exposed to a disease. However, because vaccines contain only killed or weakened forms of germs like viruses or bacteria, they do not cause the disease or put you at risk of its complications

Vaccines are also critical to the prevention and control of infectious disease outbreaks

Historical impact

Effectiveness at population level

In the United States alone:

> Research shows that routine vaccinations for children born during 1994–2023 will have prevented about 508 million illnesses and 32 million hospitalizations and saved over 1.1 million lives

Globally, vaccines are available for more than 30 potentially dangerous or deadly diseases including cervical cancer, cholera, COVID-19, diphtheria, hepatitis B, influenza, measles, mumps, polio, rabies and others.

Effectiveness varies by vaccine and disease, but is very high for many:

For newer vaccines, such as COVID-19, vaccines are proving effective against existing variants, especially at preventing severe disease, hospitalization and death, although some variants may have a slight impact on ability to guard against mild disease and infection.

Vaccines are also considered among the most cost-effective ways to protect against infectious diseases and are described as one of the best health investments money can buy.

No vaccine is 100% effective for every person, and high coverage is needed to achieve community protection (herd immunity) and to prevent outbreaks, but the consensus of the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC) is that vaccines are a safe, rigorously tested, and highly effective tool for preventing disease, disability, and death.