Are vaccines an effective tool to prevent disease?

I'll search the latest evidence to answer whether vaccines effectively prevent disease.

Yes, vaccines are widely recognized by major health authorities as one of the most effective tools to prevent disease.

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

Evidence of effectiveness

Large-scale 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 2024 study published in The Lancet and led by the World Health Organization estimates that vaccines have saved 154 million lives worldwide over the past 50 years.

•The World Health Organisation (WHO) says between 3.5 and 5 million deaths are prevented each year by vaccinations for preventable but life-threatening diseases like diphtheria, tetanus, pertussis, influenza and measles.

•They significantly reduce the burden of infectious diseases, prevent outbreaks and save millions of lives.

Reduction in disease incidence:

•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.

•Immunizations have thwarted epidemics of once common infectious diseases such as measles, mumps, and whooping cough, and have led to the near eradication of others, such as polio and smallpox.

Level of protection:

•Vaccines are very effective at preventing disease, but they don't work all the time. Most of the recommended childhood immunizations are 90%-100% effective, according to the CDC.

•The Centers for Disease Control and Prevention (CDC) found that vaccines effectively produced immunity in 85-95 percent of patients.

•According to a sweeping global review, mRNA vaccines are safe and highly effective at preventing infectious diseases like COVID-19.

•A CDC study found risk of infection following the second dose of mRNA COVID-19 vaccines was reduced by 90% two or more weeks after vaccination.

•Vaccine effectiveness against hospitalization ranged from 75% to 95% and "Vaccines remain effective in preventing hospitalization and severe disease".

How vaccines prevent disease

Vaccines work by training the immune system to recognize and combat pathogens, reducing the incidence of diseases like measles, polio, and influenza:

> Immunizations, or vaccines ... safely and effectively use a small amount of a weakened or killed virus or bacteria or bits of lab-made protein that imitate the virus in order to prevent infection by that same virus or bacteria.

> Then, if you're ever again exposed to the actual disease-causing organism, your immune system is prepared to fight the infection. A vaccine will usually prevent the onset of a disease or else reduce its severity.

Vaccines cannot always prevent infection, but they can substantially reduce the risk of serious disease.

Even in cases where a vaccine has not given 100% immunity, the symptoms — if exposed to an infectious disease — will still usually be milder than if they had not been immunized at all. In addition, children in whom the vaccine is 100% effective protect those few who have not been completely immunized -- lessening everyone's chance of exposure to the disease — contributing to community or herd immunity.

Medical providers agree that the proven preventive benefits of vaccines far outweigh the risks of the minimal side effects associated with them.

In summary, while no vaccine is 100% effective for every individual and effectiveness varies by vaccine, age, health status and circulating strains, extensive clinical and population evidence shows vaccines are a highly effective, safe, and cost-effective public health tool for preventing infectious diseases, severe illness, complications, and death.

Citations (3)

1who.intGovernment
Vaccines and immunization: Vaccine safety
Backs: “Yes, vaccines are widely recognized by major health authorities as one of the most effective tools to prevent disease.”
2who.intGovernment
Vaccines and immunization: Vaccine safety
Backs: “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.”
3webmd.comCommercial contentquality 0.84
Immunizations and Vaccines
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. Immunizations have thwarted epidemics of once common…”