Are vaccines an effective tool to prevent disease?

Yes, vaccines are highly effective and are widely considered one of the most successful and cost-effective public health interventions in human history.

Global health authorities, including the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC), agree that vaccines are a vital tool for saving lives, reducing healthcare costs, and preventing severe illness and disability.

The scientific consensus on the effectiveness of vaccines is supported by several key factors:

1. Lives Saved and Diseases Prevented

•Millions of Lives Saved Annually: Immunizations prevent between 3.5 million and 5 million deaths globally every year from diseases like diphtheria, tetanus, pertussis (whooping cough), influenza, and measles.

•Historical Successes: Vaccines are responsible for the complete eradication of smallpox—a disease that once killed millions—and have brought polio to the brink of global eradication.

•Reduction in Disease Rates: In countries with high vaccination rates, cases of once-common childhood diseases like measles, mumps, rubella, and Hib meningitis have plummeted by 99% or more compared to the pre-vaccine era.

2. High Individual Efficacy

Most routine childhood vaccines are highly effective, typically offering 90% to 99% protection against target diseases when the recommended schedule is followed. For example:

•Two doses of the MMR (Measles, Mumps, and Rubella) vaccine are about 97% effective at preventing measles.

•The polio vaccine is 99% to 100% effective after a complete series.

3. Protection Against Severe Illness

While no vaccine is 100% effective at preventing all infections (meaning "breakthrough infections" can happen), they are incredibly powerful at preventing severe illness, hospitalization, and death. If a vaccinated person does contract the disease, they are much more likely to experience mild symptoms rather than life-threatening complications.

4. Community Protection (Herd Immunity)

When a high percentage of a population is vaccinated, it becomes difficult for an infectious disease to spread. This is known as herd immunity or community protection. It is essential for protecting vulnerable individuals who cannot receive certain vaccines, such as newborn babies, pregnant women, and people with weakened immune systems (e.g., those undergoing cancer treatments).

5. Rigorous Safety and Testing

Before a vaccine is approved for the public, it undergoes rigorous, multi-stage clinical trials involving thousands of volunteers to ensure it is both safe and effective. After approval, health agencies continuously monitor vaccine safety and efficacy in the real world. While vaccines can have mild, temporary side effects (like a sore arm or low-grade fever), serious side effects are extremely rare. A person is far more likely to be seriously harmed by the actual disease than by its vaccine.

Citations (10)

1sc.govGovernment
sc.gov
Backs: “Yes, vaccines are highly effective and are widely considered one of the most successful and cost-effective public health interventions in human history.”
2cdc.govGovernment
cdc.gov
Backs: “Yes, vaccines are highly effective and are widely considered one of the most successful and cost-effective public health interventions in human history.”
3who.intGovernment
who.int
Backs: “Yes, vaccines are highly effective and are widely considered one of the most successful and cost-effective public health interventions in human history.”
4pfizer.comNot yet classified
pfizer.com
Backs: “Global health authorities, including the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC), agree that vaccines are a vital tool for saving lives, reducing healthcare costs, and preventing severe illness and disability.”
5cdc.govGovernment
cdc.gov
Backs: “Historical Successes: Vaccines are responsible for the complete eradication of smallpox—a disease that once killed millions—and have brought polio to the brink of global eradication. Reduction in Disease Rates: In countries with high vaccination rates, cases of once-common childhood diseases like measles, mumps,…”
6ama-assn.orgNonprofits and think tanks
ama-assn.org
Backs: “Reduction in Disease Rates: In countries with high vaccination rates, cases of once-common childhood diseases like measles, mumps, rubella, and Hib meningitis have plummeted by 99% or more compared to the pre-vaccine era. 2.”
7immunizeforgood.comNot yet classified
immunizeforgood.com
Backs: “Most routine childhood vaccines are highly effective, typically offering 90% to 99% protection against target diseases when the recommended schedule is followed. For example:”
8cdc.govGovernment
cdc.gov
Backs: “If a vaccinated person does contract the disease, they are much more likely to experience mild symptoms rather than life-threatening complications. 4.”
9who.intGovernment
who.int
Backs: “If a vaccinated person does contract the disease, they are much more likely to experience mild symptoms rather than life-threatening complications. 4.”
10who.intGovernment
who.int
Backs: “Before a vaccine is approved for the public, it undergoes rigorous, multi-stage clinical trials involving thousands of volunteers to ensure it is both safe and effective. After approval, health agencies continuously monitor vaccine safety and efficacy in the real world.”