Vaccines have greatly reduced the prevalence of diseases since Edward Jenner developed the world’s first vaccine in 1796 against smallpox. Today, vaccines have saved more lives than any other medical invention. The average American gets vaccinated dozens of times in their lifetime to prevent severe illness, yet very few know the intricacies of how vaccines work.
To increase immunization rates and keep our communities healthy, it’s important for more people to have a deeper understanding of the vaccine process. Healthcare providers can help spread awareness about the value of vaccines and debunk the misconceptions of vaccine safety by explaining how vaccination protects us against disease and death.
What is Immunity?
Immunization is one of the most cost-effective public health interventions, preventing about four million deaths every year. The U.S. Centers for Disease Control (CDC) defines immunity as protection against a disease, and explains how immunity can be either passive or active. Antibodies produced by another human being, such as mother’s passing on antibodies to their baby during pregnancy, provide passive immunity. This allows for immediate protection but diminishes within months. Active immunity comes from exposure to a disease-causing organism—either through natural infection or through vaccination—and is slower to develop but lasts longer. A person is considered immune when they are partially or fully resistant to the bacteria or viruses that cause disease.
Not everyone can get vaccinated due to underlying conditions, age, or allergies to components of vaccines. These individuals rely on protection from others around them who are vaccinated, underscoring the significance of herd immunity. When a certain immunity threshold is reached, vulnerable individuals are protected from infection because the spread of disease is limited.
How Vaccines Protect Us
Vaccines work by imitating an infection to teach the immune system how to recognize and respond to a germ, engaging the body’s natural defenses. While no single vaccine provides 100% protection, the process of immunization is much safer than getting naturally infected. A vaccine affords us protection with smaller quantities of virus or bacteria, the control of scheduling the exposure, and the peace of mind of achieving immunity without experiencing severe illness.
The way a vaccine works also depends on what it’s made of. The key active ingredient in vaccines is antigens, the weakened or inactive parts of a particular organism that triggers an immune response within the body. It’s worth noting that newer vaccines contain the blueprint for producing antigens rather than the antigen itself. Most of the other ingredients in vaccines are in our environment, such as things we eat and drink and approved medications. These ingredients are used in very small quantities and when the vaccines reach the body, the trace leftover amounts are safe for humans.
Types of Vaccines
As of 2024, there are approved vaccines for about 30 diseases including 21 dangerous or deadly diseases. All vaccines have the same purpose: to help the body learn how to defend itself from disease without the dangers of infection. However, not all vaccines are created equal. Some vaccines are a one-time dose, and others require multiple doses given weeks, months, or years apart. There are also different methods of vaccine development and emerging vaccine technologies including the recent validation of messenger RNA (mRNA) technology. The various types of vaccines function in diverse ways:
Live, attenuated vaccines contain a weakened form of the virus
Inactivated vaccines use the killed version of the germ that causes the disease
Toxoid vaccines prevent diseases caused by bacteria that produce toxins in the body
Subunit vaccines contain only a part of the germ that is best suited to stimulate the immune system
Conjugate vaccines use a harmless protein attached to the bacteria’s sugar coating that the immune system can recognize
mRNA vaccines contain germ mRNA to teach the cell how to make a protein the body will recognize as foreign
Viral vector vaccines use a modified version of a harmless virus to deliver genetic code to the body’s cells, which make proteins that the immune system can recognize
Vaccines are the safest, most effective way to protect patients and our communities against preventable diseases. Physicians can help their patients better understand how vaccines work and the importance of staying on track with their immunization schedule. At Atlantic Health Partners, we aim to help physicians prepare for these conversations by equipping them with valuable and informative resources. Learn more through our Resource Center.