“Vaccines are a Cliff Notes version of disease”

~Justin McElroy, Sawbones podcast, episode 49

When talking about almost any pandemic, it is impossible to avoid the topic of vaccines. The root of the word vaccine means "of or from the cow" in Latin, satirized by the French artist Honoré Daumier in the first illustration below. Throughout history, vaccines have greatly reduced the number and the impact of infectious diseases that once regularly harmed or killed many infants, children, and adults. However, the germs that cause vaccine-preventable diseases still exist and can be spread to people who are not protected by vaccines. That is why vaccination still plays a critical role in protecting the health of communities and individuals.

So how exactly do vaccines work? It helps to first look at how the body fights illness. When germs, such as bacteria or viruses, infect the body, they attack and multiply, causing illness. The immune system has several tools for fighting infections, including white or immune cells in our blood. These white cells consist primarily of macrophages, B-lymphocytes, and T-lymphocytes:

• Macrophages are white blood cells that swallow up and digest germs, plus dead or dying cells. The macrophages leave behind parts of the invading germs called antigens. The body identifies antigens as dangerous and stimulates antibodies to attack them.

• B-lymphocytes are defensive white blood cells. They produce antibodies that attack the antigens left behind by the macrophages.

• T-lymphocytes are another type of defensive white blood cell. They attack cells in the body that have already been infected.

The first time the body encounters a germ, it can take several days to make and use all the germ-fighting tools needed to get over the infection. After the infection, the immune system remembers what it learned about that disease by keeping a few T-lymphocytes, called memory cells, that go into action quickly if the body encounters the same germ again. Memory cells allow the immune system to react against the infection quicker and more effectively. However, sometimes the immune system cannot respond quickly enough and fight off the germs before they cause serious damage to the body. This damage can be permanent or even fatal.

The goal of vaccination is to prevent this risk by preparing one’s immune system against a certain disease before encountering it in the wild. Simply put, vaccines imitate an infection. This type of infection, however, almost never causes illness, but it does cause the immune system to produce T-lymphocytes and antibodies. Sometimes, after getting a vaccine, the imitation infection can cause minor symptoms, such as fever, which is normal and should be expected as the body builds immunity. Once the imitation infection goes away, the body is left with a supply of memory cells, as well as B-lymphocytes that will remember how to fight that disease in the future.

It typically takes a few weeks for the body to produce T-lymphocytes and B-lymphocytes after vaccination. Therefore, it is possible that a person infected with a disease just before or just after vaccination could still develop symptoms and get a disease, because the vaccine has not had enough time to provide protection. For that reason, the CDC recommends getting certain vaccinations done at specific times of the year. For example, you should get a flu shot before or just as the flu season starts.

Read more about the history of vaccinations.

References

Chung, Eun Hee. "Vaccine Allergies." Clinical and Experimental Vaccine Research, Vol. 3, No. 1 (January 2014): 50–57.

McElroy, Dr. Sydnee and McElroy, Justin. "Vaccines." Sawbones: A Marital Tour of Misguided Medicine, episode 49, July 8, 2014.

Montagu, Lady Mary Wortley. "Smallpox Vaccination in Turkey." Internet History Sourcebooks Project.

Shchelkunov Sergei. "Emergence and Reemergence of Smallpox: The Need for Development of a New Generation Smallpox Vaccine." Vaccine, vol. 29 Suppl 4 (2011): D49-53.

"Vaccination." Wikipedia.com.

"Vaccines and Immunizations: Basics and Common Questions." CDC.gov.

Navigation: Click on the "Source" links for larger images and additional information.

In recent years, a growing number of people have been protesting mandatory vaccinations, and some of them go as far as to claim that the risks of vaccination outweighs the positive effects. It is true that even in healthy individuals vaccines might cause side-effects. But so do the diseases they prevent - and they are much more likely to have serious and even fatal consequences.

Unfortunately, there are still many regions where some or any vaccines are not available or very hard to get. So living in a place with easy access to immunizations is certainly a privilege. And for every single one of us who has this privilege, it is a moral and civic duty to use it for ourselves and for the common good. Only through collective effort can we ensure the safety of the most vulnerable members of our community.

Looking back at our collective history, humanity has always given itself a hard time. We have definitely caused each other a lot of trouble on top of countless plagues and natural disasters. And our shared track record seems to contain very few clear wins. However, vaccination? It is absolutely one of them.