Are vaccines an effective tool to prevent disease?

Vaccines remain one of medicine's most effective tools — I'll gather current evidence on how well they prevent disease.

Yes, vaccines are one of the most effective tools to prevent disease. This is supported by overwhelming scientific evidence and global public health data:

Evidence for high effectiveness:

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

•Vaccines are the most effective tool to prevent the outbreak of many dangerous diseases, including polio and measles.

•Vaccines are among the most cost-effective ways to protect against infectious diseases. The introduction of a vaccine has, in many cases, led to a very large decrease in the incidence of the targeted disease — such as the 96% decrease in the incidence of polio that occurred within 7 years of the introduction of the Salk and Sabin polio vaccines.

•Strategic vaccination campaigns have virtually eliminated diseases that previously were common in the United States, including diphtheria, tetanus, poliomyelitis, smallpox, measles, mumps, rubella, and Haemophilus influenzae type b meningitis.

•Vaccines are considered one of the greatest medical achievements. They have eradicated smallpox and reduced global child mortality and long-term disabilities from vaccine-preventable diseases.

•In 1980, the World Health Organization (WHO) declared smallpox eradicated worldwide. Smallpox was the first, and to date the only, human disease to be completely eliminated through deliberate human actions. This was not achieved through a miracle cure or a breakthrough in medicine but through a vaccine administered systematically and in a coordinated manner on a global scale.

Large scale impact on lives saved:

•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 study published in The Lancet, the landmark 2024 WHO study, modeled five decades of the Expanded Programme on Immunization and found that vaccination against 14 key pathogens has saved an estimated 154 million lives worldwide since 1974, the vast majority of them in early childhood.

•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.

•Vaccines against deadly diseases save 2 to 3 million lives each year.

•For children born in the U.S. from 1994 to 2023, routine childhood vaccinations will prevent 1.13 million deaths, 32 million hospitalizations and 508 million illnesses, according to a study the Centers for Disease Control and Prevention (CDC) published.

How vaccines work:

Beyond individual protection, vaccines generate collective benefits often referred to as herd immunity. This form of immunity protects people who cannot be vaccinated because the virus or bacterium encounters fewer hosts susceptible to infection.

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

Vaccines do not provide 100% protection for every individual in every case — effectiveness can vary by disease, vaccine type, variant, age, immune status, and waning immunity over time, which is why boosters and high coverage are important — but at the population level they dramatically reduce incidence, severe disease, hospitalization, disability and death, and are significantly safer than risking the natural infection. The diseases they prevent — such as measles, meningitis, hepatitis B or polio — can be deadly or cause severe illness and disability including blindness, deafness, paralysis, brain damage, infertility, cancer, birth defects and death.

Vaccines undergo rigorous testing through multiple phases of clinical trials and continuous safety monitoring at local, national, regional and global levels before and after approval.

If you are making decisions about vaccination for yourself or your family, consult a healthcare provider or your local public health authority for evidence-based guidance on recommended vaccines and schedules.

Citations (3)

1who.intGovernment
Vaccines and immunization: Vaccine safety
Backs: “This is supported by overwhelming scientific evidence and global public health data:”
2cdc.govGovernment
Achievements in Public Health, 1900-1999: Control of Infectious Diseases
Backs: “The introduction of a vaccine has, in many cases, led to a very large decrease in the incidence of the targeted disease — such as the 96% decrease in the incidence of polio that occurred within 7 years of the introduction of the Salk and Sabin polio vaccines. Strategic vaccination campaigns have virtually eliminated…”
3medscape.comNews and mediaquality 0.93
Vaccines Saved Millions: The Success That Became Invisible
Backs: “Smallpox was the first, and to date the only, human disease to be completely eliminated through deliberate human actions. This was not achieved through a miracle cure or a breakthrough in medicine but through a vaccine administered systematically and in a coordinated manner on a global scale.”