August is National Immunization Awareness Month (NIAM), observed each year to highlight how critical it is for people of all ages to get vaccinations. Misconceptions about vaccines have kept some people from getting the protection for themselves and their loved ones that the vaccines can provide. A better understanding of how vaccines work with our immune system can help more people make informed decisions about their health.

The Impact of Vaccines

Since the late 18th century, vaccines against such diseases as polio, MMR (measles/mumps/rubella), smallpox, and influenza have helped prevent severe illness and disability, many hospitalizations, and an even greater number of deaths. In the United States, every single one of the nine vaccine-preventable diseases were reduced by more than 90% in the past century, and many have been eliminated entirely following mass vaccinations.

Vaccination avoidance can have devastating results. The 2017-2018 flu season in the U.S. was the worst on record. Nine hundred thousand people were hospitalized, and 80,000 died, including 180 children, the majority of whom were not vaccinated, according to former Surgeon General Dr. Jerome Adams. Now, with COVID-19 resulting in catastrophic death and disability rates worldwide, it’s vital that people take advantage of the available vaccines. COVID-19 vaccines have been shown to not only help prevent severe illness, but also to relieve lingering symptoms experienced by some COVID long-haulers. 

Your Immune System

To understand how vaccines work, it helps to know how our bodies fight illness. When a virus or other germ invades your body, it multiplies as quickly as it can and attacks your cells. White blood cells, the soldiers of our immune system, gather and mount a counterattack against the invader cells. There are three kinds of white blood cells: 

• Macrophages, which surround, swallow, and digest germs, dying, and dead cells, leaving behind traces of the germs, called antigens.
• B-lymphocytes, which produce antibodies that attack the antigens.
• T-lymphocytes, which attack cells in your body that have already been infected.

Your Immune System, COVID-19, and Vaccines

A COVID-19 vaccine helps your body develop immunity to the coronavirus without your having to get infected and become ill. Following a vaccination, it can take several weeks for your body to produce enough T-lymphocytes and B-lymphocytes to provide immunity, so it’s possible that you could still contract the virus soon after vaccination. Likewise, if you were infected just before getting vaccinated, the vaccine will not prevent you from getting sick. 

Some people feel ill and experience symptoms such as fever, chills, and fatigue in the day or two immediately after getting a vaccine dose. These are typically normal signs that your body is building immunity. A wide variety of experts say that the research confirms the vaccines’ safety even for people with autoimmune disorders. In fact, people with compromised immune systems are at higher risk of severe illness if infected. Certain medications can render the vaccines less effective, so discuss this possibility with your doctor, and continue to take the recommended precautions. 

Types of COVID-19 Vaccines

There are currently three main types of COVID-19 vaccines. None of these vaccines can give you COVID-19. All of them build antibodies that will remember how to fight the virus that causes COVID-19 if you become infected in the future.

• mRNA vaccines contain material from the virus that causes COVID-19 that instructs your cells to make a harmless protein (called an S protein) unique to the virus. After your cells make copies of the protein, they destroy the genetic material from the vaccine. Your body now recognizes the protein as a threat, and produces antibodies. The Pfizer and Moderna vaccines are mRNA vaccines.
• Vector vaccines involve placing genetic material from the COVID-19 virus inside a modified version of a different virus (the viral vector). The viral vector transports the genetic material into your cells. Once inside, the genetic material instructs the cells to create S proteins. Antibody production follows. The Johnson & Johnson vaccine is a vector vaccine.
• Protein subunit vaccines contain harmless proteins, just the parts of the virus that will activate your immune system. Once vaccinated, your body will recognize the protein and generate antibodies to eliminate it.

Keep in mind that the Pfizer and Moderna vaccines require two doses instead of one in order to work, and you are not considered fully vaccinated until two weeks after your second dose. The Johnson & Johnson vaccine only requires one shot, but you are still not considered fully vaccinated until two weeks after the shot.

Discuss any concerns you have about vaccines with your healthcare provider.

*Centers for Disease Control and Prevention. (2021, July 20). National Immunization and Awareness Month [Website]. https://www.cdc.gov/vaccines/events/niam/index.html