Are vaccines an effective tool to prevent disease?

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

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

What major health organizations say

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

Other authorities describe vaccines similarly:

•Vaccines remain the most effective tool we possess for preventing disease and improving public health

•Vaccines are the best defense we have against infectious diseases

•Undoubtedly, vaccines are the most effective and safe weapons available to public health for the primary prevention of infectious diseases

•Vaccination is the most effective method of preventing infectious diseases

Immunization is described as 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 and are also critical to the prevention and control of infectious disease outbreaks. They underpin global health security and are a vital tool in the battle against antimicrobial resistance.

No vaccine is 100% safe or effective for everyone because each person's body reacts to vaccines differently, but population-level effectiveness is very high.

How they work

Vaccines differ from other medical drugs in two important ways - they are designed to prevent disease, rather than treat it.

They do this by priming a person’s immune system to recognise a specific disease-causing bacteria, virus or other pathogen. This “memory” can last years, or in some cases for life, which is why vaccination can be so effective, stopping people from getting sick rather than waiting until disease occurs.

Specifically:

•Vaccines work by imitating an infection — the presence of a disease-causing organism in the body — to engage the body's natural defenses. The active ingredient in all vaccines is an antigen, the name for any substance that causes the immune system to begin producing antibodies.

•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.

We now have vaccines to prevent more than 30 life-threatening diseases and infections, helping people of all ages live longer, healthier lives.

Evidence of effectiveness

Large numbers of lives saved:

•Over the past 50 years, essential vaccines against just 14 diseases have saved at least 154 million lives.

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

•Vaccines save up to 3 million lives each year worldwide from infectious diseases, such as hepatitis, diphtheria, tetanus, measles and polio.

•It is estimated that between two and three million child deaths are averted annually through vaccination against diphtheria, tetanus, pertussis and measles.

In the United States, routine vaccination of children born during 1994 to 2023 will have prevented 508 million illnesses saved over 1 million lives, and 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.

Disease eradication and control:

•Widespread immunity due to vaccination is largely responsible for the worldwide eradication of smallpox and the restriction of diseases such as polio, measles, and tetanus from much of the world.

•Vaccination has made enormous contributions to public health, including the eradication of one dreaded disease, small pox, and elimination of poliomyelitis from all but a handful of countries.

In summary, scientific evidence and global health data from the World Health Organization (WHO) and Centers for Disease Control and Prevention (CDC) consistently show that vaccines are a highly effective, safe, and cost-effective tool to prevent infectious diseases, reduce severe complications, hospitalizations and deaths, and control or eradicate diseases at the population level when coverage is high.

Citations (2)

1who.intGovernment
Vaccines and immunization: Vaccine safety
Backs: “Yes — vaccines are one of the most effective tools available to prevent disease. What major health organizations say”
2who.intGovernment
Vaccines and immunization
Backs: “Undoubtedly, vaccines are the most effective and safe weapons available to public health for the primary prevention of infectious diseases. Vaccination is the most effective method of preventing infectious diseases. Immunization is described as a global health success story, saving millions of lives every year.”