Germs are all around us and impossible to avoid. There are many precautionary measures we can take to protect our bodies from germs, and our body even has natural defenses such as mucus and microscopic hairs, but sometimes, we need help to fight harmful pathogens (organisms that cause disease). When a pathogen is introduced to the body, the body responds by triggering its immune system.

The Immune System

When harmful germs such as bacteria or viruses enter the body, they attack and multiply, leading to an infection and then illness. The National Cancer Institute defines the immune system as a complex network of cells, tissues, organs, and substances that assist the body in fighting infections and disease. This complex system contains white blood cells, the spleen, tonsils, lymph nodes, bone marrow, and much more.

White blood cells consist of macrophages, B-lymphocytes, and T-lymphocytes.

T-lymphocytes: A defensive white blood cell that attacks infected cells in the body.
B-lymphocytes: A defense white blood cell that generates antibodies to attack the antigens left behind by macrophages.
Macrophages: White blood cells that swallow and digest germs, dead cells, or dying cells. They leave behind parts of the invading germs called antigens, which are identified as dangerous and stimulates the antibodies to attack them.

It takes the body several days to produce and utilize all the germ-fighting tools to fight the infection or illness. After the infection, however, the immune system utilizes T-lymphocytes, also known as memory cells, to teach the body how to respond if the same illness is encountered again.

How do Vaccines Work?

Vaccines develop immunity against an illness by imitating the infection, causing the immune system to produce T-lymphocytes and antibodies. This treatment rarely causes illness, but a few side effects are expected, which can be discussed with health professionals. Once the imitated infection is no longer present in the body, the immune system is equipped with the necessary memory cells to properly fight the illness if encountered in the future. It typically takes a few weeks for the body to produce the necessary T-lymphocytes and B-lymphocytes.

Types of Vaccines

There are five primary types of vaccines that are utilized in the U.S. These practices differ from region to region around the globe, depending on their resources and needs.

Live, attenuated vaccines: These vaccinations are designed to fight viruses and bacteria. They contain a version of the living virus or bacteria. However, this duplicate illness is weakened so that it does not cause harm to the vaccine recipient. These vaccines are great teachers of the immune system and are very effective in teaching the body how to fight off specific diseases.
Inactive vaccines: These vaccines also fight viruses and bacteria and are created by inactivating the germ during the process of making the vaccine. Inactivated vaccines produce immune responses differently than live vaccines, and oftentimes require multiple doses to build up and maintain immunity.
Toxoid vaccines: These vaccines prevent diseases caused by bacteria that produce toxins in the body. Similar to other vaccines, the toxins are weakened in the process of creating the vaccine. When the immune system is introduced to a toxoid, it’s able to fight natural toxins in the future.
Subunit vaccines: Instead of containing the entire pathogen like other vaccines, the subunit vaccine only includes the antigens that stimulate the immune system. This vaccine is designed to be safer and easier to create. This means side effects are less common.
Conjugate vaccine: This type of vaccine combines a weak antigen and a strong antigen. Different kinds of bacteria have antigens with an outer coating of sugar-like substances called polysaccharides. This sugar-like coating makes it more difficult for immature immune systems to recognize it and properly respond. This method helps the immune system create a stronger response to the weak antigen.

Many people, especially babies and teenagers, may need more than one dose when receiving a vaccine for the first time. It’s common for the initial exposure to a vaccine will not be sufficient to build complete and efficient immunity.

Herd Immunity

Ever wondered why some vaccines are required for school or other social activities? Vaccines don’t just work on the individual level - they are also responsible for protecting an entire population. If one person was vaccinated against a dangerous illness, it wouldn’t be beneficial if the rest of the population wasn’t vaccinated for the same thing. Once enough of the population is vaccinated, the possibility of an outbreak becomes less likely. The bacteria or virus has a difficult time finding enough eligible hosts, so they eventually die out entirely. This process is known as herd immunity and is critical in protecting ourselves and the people around us.

Because new viruses, bacterias, variants, and mutations of viruses are always present and ever-changing, vaccine research is always developing as well. Our biorepository services provide various tissues from various donors. Contact us today to learn more.

Resources:

https://vaccineinformation.org/how-vaccines-work/
https://www.niaid.nih.gov/research/vaccine-types
https://www.publichealth.org/public-awareness/understanding-vaccines/vaccines-work/
https://www.cdc.gov/vaccines/hcp/conversations/downloads/vacsafe-understand-color-office.pdf