Are vaccines an effective tool to prevent disease?

Yes

Vaccines prevent disease effectively — I'll pull the latest evidence to show you how well they work.

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

Scientific and public health consensus:

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

•The WHO currently ranks vaccination as one of the most effective and cost-effective public health interventions

•There are now vaccines capable of preventing more than 30 life-threatening diseases, and immunization prevents between 3.5 million and 5 million deaths each year from diseases such as diphtheria, tetanus, pertussis, influenza, and measles

Evidence of effectiveness:

•Over the past 50 years, essential vaccines against just 14 diseases have saved at least 154 million lives. During the same period, vaccination has contributed to 40% of the drop in infant deaths. A 2024 WHO study modeled found vaccination against 14 key pathogens has saved an estimated 154 million lives worldwide since 1974.

•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.

•In 2013, it was estimated that 103 million cases of childhood diseases in the United States had been prevented by the use of vaccines since 1924.

•Between 2000 and 2023, vaccination is estimated to have saved approximately 60 million lives worldwide from measles alone, with measles vaccines used safely and effectively for more than 50 years.

•Vaccines prevent an estimated 2 to 3 million deaths each year according to the CDC.

How vaccines prevent disease:

•Vaccines are highly effective in preventing infectious diseases and fostering herd immunity, which protects those who cannot be vaccinated. Vaccinated individuals act as barriers to disease transmission, limiting spread within communities.

•Vaccines not only protect the vaccinated individuals, they also reduce the likelihood that an infected individual will spread the pathogen to others - This concept is referred to as herd immunity and can prevent the spread of the disease.

•Vaccines lower your chance of getting— and spreading—serious diseases like measles, flu, COVID-19, and HPV. If vaccinated people do get sick, symptoms are usually milder.

•Vaccines are usually around 90-99% effective. For COVID-19 vaccines, effectiveness is shown as measurable reduction in severe outcomes — many studies emphasize strong protection, especially against hospitalization and critical illness in older adults. A global review found that mRNA vaccines are safe and highly effective at preventing infectious diseases like COVID-19.

Historic successes:

•In 1980, the World Health Organization (WHO) declared smallpox eradicated worldwide... through a vaccine administered systematically and in a coordinated manner on a global scale. Key achievements include the eradication of smallpox and the 99% reduction of polio cases.

Like any medicine, vaccines can cause side effects, but these are usually very minor and of short duration, such as a sore arm or a mild fever, and more serious side effects are extremely rare. A person is far more likely to be seriously harmed by a disease than by a vaccine.

Vaccines undergo rigorous and stringent testing through multiple phases of clinical trials before approval and continue to be monitored for safety after introduction.

This information is for educational purposes and not medical advice. Talk to your healthcare provider about vaccination decisions.

Citations (3)

1who.intGovernment
Vaccines and immunization: Vaccine safety
Backs: “Yes, vaccines are considered one of the most effective tools to prevent disease. Scientific and public health consensus:”
evidence, reference entry, points to yes. Claim: Vaccines are considered one of the most effective tools to prevent disease, according to WHO-based information on vaccines and immunization.
2medscape.comNews and mediaquality 0.93
Vaccines Saved Millions: The Success That Became Invisible
Backs: “Scientific and public health consensus: Vaccination is one of the most effective ways to prevent diseases. The WHO currently ranks vaccination as one of the most effective and cost-effective public health interventions”
evidence, article, points to yes. Claim: Scientific and public health consensus that vaccination is among the most effective, cost-effective ways to prevent disease and saves millions of lives.
3cdc.govGovernment
Vaccines and the Diseases they Prevent
Backs: “A 2024 WHO study modeled found vaccination against 14 key pathogens has saved an estimated 154 million lives worldwide since 1974. 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.”
statistic, data page, points to yes. Claim: Vaccination against 14 pathogens saved an estimated 154 million lives since 1974; routine childhood vaccines prevent hundreds of millions of illnesses and over a million deaths.