How does a vaccine actually work?

August 28, 2024

4 minutes

Personal Health

It's tough to watch the news today without hearing an opinion on vaccines, and it can be hard to sort through all of the misinformation to get the truth about vaccine safety and efficacy. At Evidation, we understand the confusion, and we're here to help. In this article, we'll dig into the science behind vaccines, different types of immunizations, how vaccines create immunity, and common misconceptions about immunizations.

The science behind vaccines: How does immunization work?

Whether you're curious about fighting the flu with a yearly vaccination or you're unsure about how vaccines will affect your child, it's important to understand the basic tenets of how vaccines work.

Let's take a look at the steps your body goes through when you receive an immunization:

• Introduction of antigen(s): A vaccine contains weakened or inactivated parts of an organism, or antigen, that triggers the body's immune response. The antigen in the vaccine could be a piece of a virus or bacteria, a protein, or a weakened or killed form of the pathogen.
• Immune system response: When a vaccine is introduced to the body, the immune system recognizes a foreign substance (the antigen). The immune system then responds with pathogen-fighting white blood cells including T-lymphocytes (T-cells) and B-lymphocytes (B-cells).
• Production of antibodies: B-cells go to work producing antibodies (proteins) designed to fight the antigen introduced by the vaccine.
• Formation of memory cells: Some of the B-cells and T-cells released by the immune system become memory cells that remain in the body long after the initial immune system response. These cells "remember" the pathogen and are able to attack it in the event that it's introduced through a non-vaccine source.
• Immunity development: If the body is later exposed to the actual pathogen, the immune system can quickly recognize and respond, thanks to the memory cells. The antibodies and immune cells can effectively neutralize the pathogen before it causes illness.

Types of vaccines

Researchers use a number of factors to determine what type of vaccine will be most effective against each pathogen.

Common types of vaccines include:

• Live-attenuated vaccines: These vaccines contain a version of a living microbe that has been weakened so that it can't cause disease in healthy people. The measles, mumps, and rubella vaccine (MMR) is an example.
• Inactivated vaccines: These are vaccines that contain a killed version of the microbe (this includes the polio vaccine).
• Subunit vaccines: Also known as recombinant, polysaccharide, and conjugate vaccines, these vaccines contain pieces of a pathogen (like a protein or sugar). Vaccines against HPV and hepatitis B fall into this category.
• mRNA vaccines: These immunizations instruct cells to produce a protein that triggers the body's immune response, and include some types of the COVID-19 vaccine.

Vaccine development process

Vaccine development is a complex, multi-stage process that can take many years.

The main stages of vaccine development include:

• Exploratory stage: In this stage, scientists conduct research to identify antigens that could help to treat or prevent a disease and potential targets (like parts of the virus or bacterium) are identified.
• Preclinical stage: Researchers use cell cultures and animal testing to determine the safety and efficacy of the vaccine.
• Clinical development: This stage involves three phases of human testing, each with expanded numbers of volunteers.
• Regulatory review and approval: Developers submit a licensing application to the U.S. Food and Drug Administration (or the equivalent governing body in the country in which the vaccine is being developed). The vaccine receives approval for public use if it meets the required standards.
• Manufacturing, quality control, and surveillance: Vaccines are regularly tested for safety, potency, and side effects during the manufacturing process, as well as throughout the time period for which the vaccine is distributed to the public.

Common misconceptions about vaccines

You want to do what's best for your family, but misinformation can make it difficult to understand the realities of vaccine safety.

There are many misconceptions about vaccines, including:

• Myth: Vaccines cause autism.

• Truth: Extensive research shows that there is no connection between vaccines and autism.

• Myth: Vaccines contain harmful ingredients.

• Truth: The ingredients in vaccines are present in very small amounts and are safe. They are included to ensure the vaccine's effectiveness and stability. Ingredients like formaldehyde and aluminum are present at levels much lower than what we encounter in daily life.

• Myth: Natural immunity is better than vaccine-acquired immunity.

• Truth: Natural infections can cause complications and death. Vaccines are a safe, effective way to develop immunity without the risks of contracting an illness.

Evidation’s resources on vaccines

At Evidation, we're here to provide you with everything you need to know regarding the latest vaccine research. We're proud to partner with medical research organizations around the world to help our planet become a healthier place. Click here to check out our latest news, and click here to see more about our vaccine-specific research. Be sure to check back regularly to learn more.

Evidation: Supporting your health and driving research forward

At Evidation, we're committed to helping you feel your best. When you choose to share the health data that you're already tracking with other apps, we're able to aggregate your information to provide you with personalized, content-based recommendations that can help you take your health to the next level. We also reward you for taking healthy actions, making it easier to stay on track as you work toward your wellness goals.

Vaccines are made possible with thorough health research, and at Evidation, we're doing our part to contribute to the greater good. When you sign up for our app, you can choose to share health-related data from apps you're already using to inform health research, putting the information you're already collecting to good use. We only share data with your approval and ask your permission every time.

We'd love to support you as you work to become your healthiest self. Learn more about Evidation and download our app today.