Vaccines are proven to prevent disease — I'll pull the latest data on how effective they are.
Yes, vaccines are one of the most effective tools to prevent disease, according to major health authorities and the scientific literature.
Evidence from Leading Health Authorities
•The World Health Organization states: "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 (1). During the same period, vaccination has contributed to 40% of the drop in infant deaths."
•WHO also describes: "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."
•"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."
•Major health organizations, including the World Health Organization (WHO) and the US Centers for Disease Control and Prevention (CDC), continue to recommend routine childhood immunization as one of the safest and most effective ways to prevent infectious diseases.
How Vaccines 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."
Historical Impact
Vaccines have been pivotal in controlling infectious diseases throughout history:
•"Vaccines have been pivotal in the control of many infectious diseases throughout history, such as polio, measles, and smallpox, which were eradicated through global vaccination campaigns (Henderson, 2009)."
•"Vaccination has globally eradicated smallpox"
•Historical examples show dramatic declines after vaccine introduction, 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"
Measured Effectiveness
Effectiveness is measured in clinical trials and real-world studies and varies by disease and vaccine type, but consistently shows strong protection, especially against severe disease:
•The Centers for Disease Control and Prevention (CDC) found that vaccines effectively produced immunity in 85-95 percent of patients.
•mRNA vaccines—now administered billions of times worldwide—are "safe and highly effective at preventing infectious diseases like COVID-19"
•For COVID-19 specifically:
•In 2024-25, the CDC estimates vaccination "prevented roughly 5 million medical visits, 180,000 hospitalizations, and 12,000 deaths."
•The 2024-25 COVID-19 vaccine was "an estimated 40% effective against hospital admission and 79% effective against invasive mechanical ventilation (IMV) or death"
•Vaccines are also critical to the prevention and control of infectious disease outbreaks and underpin global health security, and through widespread coverage can achieve herd immunity which protects vulnerable populations who cannot be vaccinated.
While no vaccine is 100% effective at preventing all infections and protection can wane over time requiring boosters, the scientific consensus is that the benefits far outweigh the risks. Vaccines are highly effective at preventing disease, reducing severity, hospitalization and death, and have saved hundreds of millions of lives.