How Does the COVID Vaccine Work?

Written By Sophia Mai

Jun 26, 2022 | Written By Sophia Mai in Collaboration with Brooke Culp (@underthemicroscope_biology on Instagram)

We all know that the COVID vaccine is essential for keeping ourselves and the people around us safe during the pandemic but have you ever wondered how the vaccine worked? Understanding how the vaccine works and common misconceptions can prevent misinformation, especially from online sources such as social media, and help minimize some of the harmful effects of false information. 

How Does Your Body Fight Against a Pathogen?

Pathogens such as viruses, bacteria, fungi, and parasites are organisms that can cause disease. These can be found all around us and in our bodies. The body has many defense mechanisms against harmful pathogens, for example, our skin which acts as a physical barrier against germs. However, when a pathogen infects the body, an immune response is triggered to attack or destroy the pathogen.

Pathogens are made up of several parts that are specific to that pathogen. Antigens are a component of a pathogen that induces the production of antibodies. Antigens can be surface markers or proteins on a pathogen that are used by the immune system to identify a harmful pathogen in the body. Antibodies are created to identify and stop the foreign object in the body and neutralize its effects. Antibodies are “trained” to identify a specific pathogen which is why when you inject one vaccine to fight influenza, it can’t also fight COVID because the antibodies made from the vaccine can only identify the antigens from the flu. 

When your body has not been exposed to an antigen, it takes time for the immune system to create an antibody and respond to the pathogen, and during this time, a person is more prone to becoming sick. Once the antibody for the specific antigen is made, it works with the immune system to stop the pathogen and disease. Antibodies that identify and fight one pathogen usually don’t protect against a different pathogen unless they are similar or related. It can take several days for the body to create antibodies. However, after the infection, the body creates T-lymphocytes, also called memory cells, that can quickly identify and go into action if the same pathogen attacks the body in the future.

How Do Vaccines Help Your Body Fight Pathogens?

Vaccines often contain weakened or dead parts of an organism that start an immune response within the body. The vaccine will not cause the disease in an individual, but the weakened version of the pathogen will prepare the body by making the body produce antibodies to identify the real disease more efficiently. 

Vaccines help to prevent illness in an individual and being vaccinated can help people around who cannot receive a vaccine due to underlying diseases such as HIV or autoimmune diseases. This is called herd immunity and when many people in a community have a vaccination, a pathogen can have a difficult time infecting people because most of the population has an immunity to it. Vaccines and herd immunity do not guarantee 100% protection; however, people who cannot get a vaccination will have more protection against a pathogen if those around them are vaccinated. 

How does the COVID Vaccine Work to Develop Immunity to the Virus?

Like all vaccines, the COVID-19 vaccine works to fight an illness caused by an infection from germ cells that attack our immune system. When a person is first affected by this virus, it takes several days or weeks for the body to create and use resources to help the person’s immune system fight off the infection. Some of these tools include macrophages that take and digest germs and dead cells in the body, B-lymphocytes that produce antibodies to attack small parts of the virus, and T-lymphocytes that attack cells in the body that have been previously affected. With all different kinds of vaccines, including COVID-19, the body is given a supply of T-lymphocytes, also known as "memory cells," and B-lymphocytes that will store the process of fighting the virus so the body does not have to go through the same effects it has gone through in the past. However, these "memory cells" and B-lymphocytes are typically produced a few weeks after vaccination, and because of this, it is possible for a person to contract the virus that causes COVID-19 soon after getting vaccinated. The process of building immunity through vaccination can also cause symptoms, but they are all normal signs of the body building immunity.

What goes into the process of developing vaccines?

Despite the COVID-19 vaccine’s rapid development, the process of making this vaccine available to the public followed the same taxing procedure used to produce every other vaccine. This process includes general development, clinical trials, Food and Drug Administration (FDA) approval, manufacturing, and distribution.

Starting at the beginning, vaccines are first made in a laboratory, which could take years depending on the complexity of the virus. Luckily, scientists have been studying the SARS-CoV-2 virus, which is related to COVID-19 and other coronaviruses, and have been working for years to develop vaccines against other coronaviruses, and because of this, the initial development of this vaccine was sped up. After the initial development, a vaccine is put through three phases of clinical trials to ensure it is safe and effective for everyone. Because of the rapidly spreading pandemic, the COVID-19 clinical trials were overlapped to speed up the process; no phases were skipped. The clinical trials for this vaccine included applicants from diverse ages, races, and ethnicities and collected data from the outcomes of people who were vaccinated and people who were not. A milestone was reached when no serious side effects become present after the first eight weeks, as it is uncommon for no adverse effects to become present after this time period. And although the vaccine has been released to the public, health and safety reports are still present. 

Before vaccines are accessible to the real world, the FDA must access the findings in the clinical trials and evaluate if they should and will be released to the public. For COVID-19, there were three vaccines that reached FDA standards and therefore received Emergency Use Authorization (EUA), allowing the vaccines to be distributed to the public at a faster rate than others. Before granting this approval, the FDA must also evaluate preclinical trial data, the manufacturing process, and vaccine testing results along with the clinical trial data, and because these vaccines met the requirements, they were ready for manufacturing.

After the review process, materials and resources supplied by the government were used for manufacturing and distribution. As the vaccines continue to be distributed outside the clinical trials, monitoring systems work to ensure the safety of all recipients. Along with the CDC and the FDA constantly analyzing data, multiple vaccine monitoring systems such as the Vaccine Adverse Event Reporting System (VAERS) and the Vaccine Safety Datalink (VSD) work to look over all possible safety issues that may arise after the vaccines are released to the public. Moreover, although the COVID-19 vaccines were produced at an excellent rate, the developmental process of creating vaccines was executed in the same way. 

How do mRNA and Viral Vector Vaccines work? 

When it comes to COVID-19 vaccines, there are three that have been approved by the FDA: Pfizer-BioNTech, Moderna, and Johnson & Janssen. The Pfizer-BioNTech and Moderna are messenger mRNA vaccines that differ from the Johnson & Janssen, which is a viral vector vaccine. Although these vaccines are fighting the same virus, how they do so is what makes them different.

The Pfizer-BioNTech and Moderna vaccines use genetically engineered mRNA that associates itself with the spikelike structure held on the surface of the coronavirus called the S protein. The mRNA vaccines teach the body’s cells to produce harmless S proteins that will then start an immune response to build antibodies, meaning a person will build immunity to the COVID-19 virus without getting it. In more detail, after the vaccine enters the body, muscle cells start to make coronavirus spike proteins and display them on cell surfaces. This triggers the immune system to recognize the protein, build an immune response, and create antibodies. After this process, the mRNA is broken down immediately, never entering the nucleus of the cell. The mRNA vaccines do not contain a live virus, cannot cause infection with the virus that leads to COVID-19, and do not enter the nuclei, hence making the vaccine unable to change a person’s genes. These COVID-19 mRNA vaccines have been held to the same safety and effectiveness levels as other vaccines, and only ones that are monitored and evaluated in this way are released to the public.

The third COVID-19 vaccine that was approved by the FDA, Johnson & Janssen, is a viral vector vaccine. Viral vector vaccines contain a weakened version of a virus that is different from the one trying to be attacked, in this case, the coronavirus, and teaches the body’s cells to make harmless pieces of the S protein. More specifically, genetic material from the COVID-19 virus is placed inside of a weakened, live virus. This weakened virus can also be known as the viral vector, and when this viral vector gets into a person’s cells, it delivers information from the coronavirus that causes the body to make copies of the S protein. Soon, the S proteins are displayed on the cells’ surface, causing your body to create antibodies and defensive white blood cells so when a person is infected with the virus after receiving the vaccine, the antibodies will fight it. It usually takes about two weeks for the vaccine to take full effect. Lastly, these vaccines cannot cause you to contract the COVID-19 virus or the viral vector virus, and the genetic material that is delivered is not transferred to a person’s DNA.

What are booster shots and what are their purposes?

When it comes to the COVID-19 vaccine, the main objective is to keep everyone as safe as possible from the virus. To maintain strong protection against severe coronavirus cases, a booster shot is an additional dose(s) given as further protection after the original shot has begun to decrease in effectiveness. Depending on a person’s series of vaccines, their eligibility for a booster shot will vary, and a healthcare professional should be consulted before receiving one. 

Receiving a booster shot is primarily to protect its recipient and ensure that it will not have any serious effects that may result in hospitalization. However, an additional dose of the vaccine is different from the booster and could lead to serious injury if substituted. An additional dose is for people who have a severely compromised immune system, such as people who are being treated for cancer, have had an organ transplant, or are on medication for immune support. Moreover, a COVID-19 booster shot is made and distributed to further ensure the safety of everyone who has received the vaccine previously.

What are Some of the Common Misconceptions about Vaccines?

Some common misconceptions about the COVID vaccine are: 

Vaccines can cause illness.

Vaccines do not cause illness. However, individuals can have some side effects such as soreness or a mild fever, but people do not usually have serious side effects from vaccines. Some common effects of vaccines are pain or swelling where the shot was given, mild fever, tiredness, headache, and muscle aches. 

Serious side effects from vaccines are rare. Some signs of a serious allergic reaction are difficulty breathing, face or neck swelling, a fast heartbeat, rash all over your body, dizziness, and weakness. If you are experiencing a severe allergic reaction, you should contact your healthcare provider or go to your nearest hospital. 

Vaccines contain toxic and harmful chemicals.

Many substances at large doses are toxic to humans. While certain vaccines do contain trace amounts of formaldehyde, aluminum, and mercury, they are in minute amounts and are much smaller than what is considered toxic for humans. So why are there small amounts of these substances in vaccines? Substances such as aluminum hydroxide can enhance the immune system making the vaccine more effective while formaldehyde can help kill viruses. Doctors do not want to harm people and want to protect people from dangerous diseases. 

Natural immunity is safer than receiving a vaccination.

Vaccines allow you to develop an immunity to pathogens without the harmful effects that diseases can cause without protection or antibodies. Diseases can cause serious damage and infection to the body that could be prevented by receiving a vaccination. 

Knowing the facts and misconceptions can protect you and the people around you from serious diseases. Getting vaccinated is essential to achieving herd immunity and while it doesn’t provide 100% protection, it can severely slow down the spread of COVID and protect the immunocompromised. There are many ways to address misinformation and one way is to look for credible sources such as the CDC or health professionals. Sharing correct information regarding vaccinations can eliminate the anxiety of receiving a vaccination and help others better understand the importance of getting a vaccine. 

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Give a round of applause to another collaboration! This blog was written with Brooke Culp at @underthemicroscope_biology on Instagram.

Sophia Mai
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