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What are Immunizations?

Immunizations, or vaccines, are treatments that help protect you from getting certain diseases. They work by training your immune system to recognize and combat germs like viruses and bacteria, without causing the disease itself.

Here’s how vaccines work:

Exposure to Germs

Vaccines contain antigens—small, harmless parts of a germ or a weakened/inactivated version of the germ. These parts don’t make you sick with the illness but move the immune system to respond, helping your body recognize and remember the germ.

Immune Response
When you get a vaccine, your immune system responds as if you’ve been exposed to the real disease. It makes special proteins called antibodies and activates other immune cells to fight the germ.
Making memories
After the vaccine has helped your body fight off the harmless parts of the germ, your immune system remembers how to recognize and fight that germ in the future. This means if you encounter the real germ later, your body can respond quickly and protect you from getting sick.

Vaccines are important for preventing the spread of diseases and have reduced or erased illnesses around the world, like smallpox and polio. Vaccines protect not just the people who get them but also help keep everyone safe, including those who can’t get vaccinated.

What are the different types of immunizations?

Vaccines come in different types based on how they work and what they contain. Live attenuated vaccines have weakened germs that can’t cause sickness but still trigger a strong immune response, like the measles, mumps, and rubella (MMR) vaccine. Inactivated vaccines use germs that have been killed, such as the polio vaccine, to create a milder immune response. There are also subunit vaccines that use parts of germs, toxoid vaccines that use inactivated toxins, mRNA vaccines that teach our cells to fight disease, and viral vector vaccines that use harmless modified viruses to deliver instructions to our cells. Each type of vaccine is designed to be safe and effective, depending on the disease and the people they are meant to protect.

Live Attenuated Vaccines

These vaccines contain germs that are live but weakened so they can’t make you sick. They help your body build protection by letting a weakened version of the germ stimulate your immune system. Examples include the MMR vaccine (for measles, mumps, and rubella) and the vaccine for yellow fever.

Inactivated or Killed Vaccines:

These vaccines use germs that have been killed or inactivated so they can’t make you sick. They still help your body learn how to fight the real germ. Examples include the polio vaccine and the hepatitis A vaccine.

Subunit, Recombinant, or Conjugate Vaccines
These vaccines use just parts of the germ, like proteins or sugars, instead of the whole germ. These parts help your body recognize and fight the real germ without causing disease. Examples are the HPV vaccine and the Hib vaccine.
Toxoid Vaccines

These vaccines protect against germs that produce toxins (poisons). They use inactivated toxins to help your body defend against the real toxin later. Examples include vaccines for diphtheria and tetanus.

mRNA Vaccines
These are newer vaccines that use a small piece of genetic material called mRNA to teach your cells how to make a protein that triggers an immune response. The mRNA doesn’t stay in your body long-term. Examples include some of the COVID-19 vaccines like Pfizer-BioNTech and Moderna.

Do the benefits of vaccination outweigh the risks?

Vaccination offers significant benefits that far outweigh the risks, making it a crucial public health measure. Vaccines help prevent severe illnesses, hospitalizations, and deaths caused by infectious diseases. For example, the CDC reports that vaccines have reduced the incidence of diseases like measles by over 99% in the U.S. since the introduction of the vaccine. Serious side effects from vaccines are extremely rare; for instance, the risk of severe allergic reactions is about 1 in a million doses.

In contrast, the risks of contracting vaccine-preventable diseases are much higher, with complications such as pneumonia, encephalitis, and even death. Overall, the safety and effectiveness of vaccines support their role in protecting individual and community health, demonstrating that the benefits of vaccination greatly surpass the minimal risks associated with receiving them.

Low vaccination rates in the United States have resulted in preventable outbreaks of infectious diseases that pose significant public health risks. For instance, the 2019 measles outbreak, which saw over 1,200 confirmed cases in 31 states, was primarily linked to undervaccinated communities. This outbreak was fueled by vaccine misinformation and declining vaccination rates, reversing decades of progress in measles control. Similarly, the rise of whooping cough (pertussis) cases illustrates the consequences of low immunization; the CDC reported more than 48,000 cases in 2012, the highest since 1955, attributed to waning immunity and decreased vaccination coverage. These examples underscore the critical importance of maintaining high vaccination rates to prevent outbreaks of diseases that can be easily controlled through immunization.

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