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History of Vaccines: How and Why Do Vaccines Work

Posted on July 9, 2024
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Vaccines have revolutionized public health, significantly reducing the incidence of many infectious diseases and saving countless lives globally. From their humble beginnings to modern advancements, vaccines are a testament to human ingenuity and scientific progress. 

Below, we explore the history of vaccination, how vaccines work, and why they are essential for protecting yourself and the public.

The Development of Modern Vaccines

The concept of vaccination dates back to ancient times. One of the earliest known attempts at inoculation was variolation, a practice used in several cultures to protect against smallpox. Variolation involved exposing healthy individuals to material from smallpox sores, which often resulted in a milder form of the disease and subsequent immunity. However, it wasn’t until 1796 that English physician Edward Jenner discovered that milkmaids who had contracted cowpox, a less severe disease, were immune to smallpox. He experimented by inoculating a young boy with cowpox material and later exposing him to smallpox. The boy did not contract smallpox, proving the effectiveness of this method. Jenner’s work laid the foundation for modern vaccines.

The 19th and 20th centuries saw significant advancements in vaccine development. French scientist Louis Pasteur made notable contributions, including developing the rabies vaccine in 1885. Pasteur’s work introduced the concept of attenuated vaccines, where pathogens are weakened but still capable of inducing immunity.

In 1937, Max Theiler developed a vaccine for yellow fever that remains in use today. The fight against polio saw breakthroughs with Jonas Salk’s polio vaccine in 1955, followed by Albert Sabin’s version in 1961. 

In 1945, Thomas Francis Jr. and Jonas Salk developed the first influenza vaccine at the University of Michigan. Initially used to protect U.S. soldiers during World War II, it was made available to civilians a year later. Since then, scientists have worked to combat the ever-evolving influenza virus by continuously improving flu vaccines.

The Evolution of Flu Vaccines

The influenza virus is notorious for its ability to mutate and produce new strains. The first flu vaccine marked a significant milestone, but ongoing research and development have been necessary to keep up with the virus’s changes. Seasonal flu vaccines are updated annually to protect against the most prevalent strains so that they remain effective in preventing influenza-related illnesses and deaths.

How Do Vaccines Work?

The immune system is a complex network of cells and proteins that defend the body against infections. When a pathogen invades, the immune system responds by producing specialized proteins that neutralize the infection called antibodies. Vaccines train the immune system to recognize and combat pathogens, such as viruses or bacteria. 

Once the immune system has encountered a pathogen, it remembers it and if the same pathogen tries to invade again it can mount a faster and stronger response. Vaccines leverage this process by introducing a harmless component of the pathogen, such as a protein or a weakened form of the virus, prompting the immune system to develop a memory without causing the disease.

There are several types of vaccines, each designed to produce a protective immune response:

  • Inactivated vaccines use killed pathogens (the inactivated polio vaccine).
  • Live attenuated vaccines use weakened pathogens (the measles, mumps, and rubella vaccine).
  • Messenger RNA (mRNA) vaccines use a small piece of the pathogen’s genetic material to stimulate an immune response (some COVID-19 vaccines).
  • Subunit, recombinant, polysaccharide, and conjugate vaccines include only parts of the pathogen (HPV).
  • Toxoid vaccines use a toxin (harmful product) made by the pathogen that causes a disease (tetanus).
  • Viral vector vaccines use a modified version of a different virus as a vector to deliver protection (some COVID-19 vaccines).

Flu vaccines are often either inactivated vaccines or recombinant vaccines. Both are designed to protect against the influenza virus.

Are Vaccines Safe?

Despite extensive evidence supporting the safety of vaccines, misconceptions and myths persist. Some common myths include the false belief that vaccines cause autism or that they contain harmful substances but scientific research has thoroughly debunked these myths. 

With rigorous testing and approval processes before they are made available to the public, including multiple phases of clinical trials to ensure they are safe and effective, vaccines are among the most closely monitored medical products with benefits that far outweigh any potential risks.

The Importance of Vaccination

High vaccination rates are essential for preventing outbreaks and controlling diseases. For example, the widespread use of the measles vaccine has drastically reduced the incidence of measles worldwide. Similarly, flu vaccines help prevent seasonal influenza outbreaks, reducing the burden on healthcare systems and saving lives.

One of the key concepts that makes vaccinations work is herd immunity. When a significant portion of a population is vaccinated, it reduces the overall amount of the pathogen that can spread, protecting those who cannot be vaccinated, such as infants, elderly individuals, and those with compromised immune systems.

Vaccines are a cornerstone of modern medicine that is safe, effective, and essential for maintaining public health. Getting vaccinated, especially with the annual flu shot, is the first step in the fight against preventable diseases. 

Interested in learning more about the advances in flu vaccine technology over the years? Read more on our website.

Learn More About Families Fighting Flu

Founded in 2004, Families Fighting Flu (FFF) is a national, nonprofit, 501(c)(3) advocacy organization dedicated to protecting children, families, and communities against the flu through education about the seriousness of influenza. Our organization includes families whose loved ones have suffered serious medical complications or died from influenza, as well as other advocates and healthcare professionals committed to flu education and prevention.

In honor of our loved ones, we work to increase awareness about the seriousness of the disease and to reduce the number of hospitalizations and deaths caused by the flu each year by increasing vaccination rates for everyone six months and older.  Learn more about our mission and resources here so that you can empower your family to stay healthy this flu season.

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