COVID-19 Vaccines: What’s happening?

Looking at the news and social media, a common topic of interest has been the covid vaccine. But, how exactly does it work and what’s the difference between the three CDC-recommended vaccines?

The Body’s Response to Pathogens

When the body is first exposed to an antigen, which is the subpart of a disease-causing pathogen, it does not have the ability to immediately respond in a way that will produce specific antibodies that will counteract antigens. During the time that the body is producing antibodies after facing exposure from a specific pathogen for the first time, the person is at risk of becoming sick (WHO). Even though the human body has the ability to produce antibodies, there is still a chance that a person can get sick during the first exposure, which makes getting vaccines important.

During the first exposure, the body produces antibodies, which will destroy the pathogen, along with other cells in the antibodies to stop the disease. These antibodies are specific to one antigen and will only protect against future pathogens that have similar antigens. This is why a person can get the flu multiple times. A person has antibodies for strains of flu that they have been exposed to; however since there are almost 198 variations of the influenza A virus, it is possible to get the flu again (CDC).

The primary response to an antigen also involves the production of antibody-producing memory cells. These cells will remain inactive in the body until the body is exposed to the same antigen once again. During the second exposure, the antibody response is more effective and faster because the cells do not have to go through the same signaling and production pathways as the primary response. A person will not know that their body is fighting off these antigens following the first exposure (WHO).

How Vaccines Work

The goal of vaccines is to expose the immune system to a weakened version of an antigen so that it can produce memory cells. Currently, there are three different types of vaccines that will prompt the body to produce memory cells that will protect against the COVID-19 vaccine.

• mRNA Vaccines: These vaccines contain genetic material from the virus that provides cells with instructions to create a protein that will elicit an immune response. The body views this protein as an antigen and will produce antibodies and memory cells. This protein is harmless and the genetic material from the vaccine is destroyed after the protein is made (CDC). Contrary to popular belief, mRNA vaccines do not have the ability to alter a person’s DNA.

• Protein Subunit Vaccines: Protein subunit vaccines contain an actual protein from the virus as opposed to the blueprints to produce a harmless protein. Just like with mRNA vaccines, the immune system will produce antibodies and memory cells in response to the presence of viral proteins in the body (CDC).

• Vector Vaccines: These vaccines expose the body to a modified virus that contains the genetic material for the virus that causes COVID-19. Once this virus enters the body’s cells, it works similar to the mRNA vaccines in that the genetic material will instruct the body to produce harmless viral proteins. The immune system will then react to these by producing antibodies and memory cells (CDC).

All three of the vaccine types mentioned have been thoroughly researched and will allow the body to respond quickly and effectively after exposure to the COVID-19 pathogen.

Available COVID-19 Vaccines

Currently, the three FDA-approved vaccines are the Pfizer-BioNTech, Moderna, and Johnson & Johnson Janssen vaccines. The safety and efficacy of these vaccines are continually being monitored even after FDA approval.

• Pfizer-BioNTech: The Pfizer vaccine is an mRNA vaccine that is 95% effective at preventing COVID-19 and is available to people 16 and older. Even though some protection is provided after the first dose, two doses, taken 21 days apart, are needed for full protection. Possible side effects include pain at the injection site, fatigue, headache, muscle pains, chills, joint pain, fever, and nausea (Mayo Clinic).

• Moderna: The Moderna vaccine is also an mRNA vaccine that is available to people 18 and older. It is 94% effective at preventing COVID-19. Like the Pfizer vaccine, it requires two doses and provides some protection after the first dose. However, the two doses should be taken 28 days apart. Possible side effects include pain at the injection site, fatigue, headache, muscle pain, chills, joint pain, nausea, vomiting, and fever (Mayo Clinic).

• Johnson & Johnson/Janssen: Unlike the Pfizer and Moderna vaccines, the Johnson & Johnson vaccine is a vector vaccine and is for people 18 and older. The vaccine is 66% effective at preventing the COVID-19 virus with symptoms, but it is 85% effective at preventing the COVID-19 virus with severe illness. Only one dose is needed for full protection, making the Johnson & Johnson vaccine a more convenient option for people. Possible side effects include pain at the injection site, headache, fatigue, muscle pain, chills, fever, and nausea (Mayo Clinic).

• Note: On April 13, 2021, the CDC and FDA called for a pause on the production of the Johnson and Johnson vaccine due to the development of a very rare blood-clotting disease after administration in individuals with low platelets. Out of the 6.8 million doses administered, there were 6 reported cases (Johnson & Johnson).

What This Means

In the end, getting vaccinated is one of the most important steps you can take to protect yourself and others around you from getting COVID-19. All three of the currently available vaccines are safe and effective, and most of the time, the decision on which vaccine to get comes down to availability or restrictions due to allergies. After you have been fully vaccinated, remember to continue to take precautions in public places or with unvaccinated people.

Sources

"Comparing The Differences Between COVID-19 Vaccines - Mayo Clinic". Mayo Clinic, 2021, https://www.mayoclinic.org/coronavirus-covid-19/vaccine/comparing-vaccines.

"Different COVID-19 Vaccines". Centers For Disease Control And Prevention, 2021, https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines.html.

"How Do Vaccines Work?". Who.Int, 2021, https://www.who.int/news-room/feature-stories/detail/how-do-vaccines-work.

"Johnson & Johnson Statement On COVID-19 Vaccine". Content Lab U.S., 2021, https://www.jnj.com/johnson-johnson-statement-on-covid-19-vaccine.

"Types Of Influenza Viruses". Centers For Disease Control And Prevention, 2021, https://www.cdc.gov/flu/about/viruses/types.htm

"Understanding How COVID-19 Vaccines Work". Centers For Disease Control And Prevention, 2021, https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/how-they-work.html.