COVID-19 Vaccine: Vaccine Types, How They Work, and More

Reviewed by 
Dr. Brian Kurtz, DO
Article at a glance
  • Vaccines mimic the viruses they target to aid a patient’s body in building immunity against that particular virus. To learn more about how vaccines function in the human body, read this section.

  • Two vaccines are currently being distributed within the United States with three more undergoing phase three clinical trials. To learn more about the Pfizer vaccine, read this section. To learn more about the Moderna vaccine, read this section.

  • The Center for Disease Control and Prevention (CDC) has provided the United States with their recommendations on how the COVID-19 vaccines should be made available to the public. To learn more about the COVID-19 vaccine timeline, read this section.

  • There are many benefits to receiving the COVID-19 vaccine such as personal health and the protection of those around you. To learn more about COVID-19 vaccine benefits, read this section.

Covid 19 vaccine 4

With COVID-19 threatening every nation in the world, the race to produce a safe and effective vaccine was on. While vaccines normally take a minimum of six years to be developed, studied, and manufactured, the Modern and Pfizer coronavirus vaccines were readily produced within a year. Due to modern technological advances and past studies linked to gaining immunity over COVID-19, the vaccine was able to be produced at rapid speeds. With recommendations from the Center for Disease Control and Prevention, each state has approved their own COVID-19 vaccine timeline for their residents, leaving many eager and hopeful that 2021 can put an end to this pandemic.

How Vaccines Work

When a virus enters the body, it begins to multiply, attack, and create an infection. The body responds and fights a virus through the use of its two types of blood cells: red blood cells which carry oxygen and white blood cells which fight infection. From there, white blood cells can be categorized into three different types that help the body fight infection in different ways. The first type is macrophages and their role is to swallow and digest germs and dying cells. Once these germs or dying cells are processed, macrophages leave behind antigens (sections of invading germs). B-lymphocytes are the second type of white blood cell and their role is to produce antibodies that attack and fight off the antigens left behind by macrophages. Lastly, there are T-lymphocytes which work on attacking cells in the body that have already been infected. Once the infection is over, a human’s immune system retains a few T-lymphocytes that remember particular viruses and can trigger B-lymphocytes to attack in case of future infections.

The COVID-19 vaccines that are currently available in the United States are mRNA vaccines. Many vaccines are designed and produced to mimic a virus’ infection while using a killed or weakened germ. However, an mRNA vaccine is unique, providing our cells with instructions on how to make a spike protein which exists on the surface of the virus that causes COVID-19. Once this spike protein is made, our body recognizes that it’s not meant to be there, thus triggering an immune response and the production of antibodies. After this process is complete, our body then remembers how to fight off the virus if it ever enters our body in the future.

Vaccine Types

There are currently two vaccines available for broader use and three vaccines undergoing phase three clinical trials. The two vaccines being distributed include the Pfizer vaccine and the Moderna vaccine. The three vaccines in phase three clinical trials in the United States include AstraZeneca’s COVID-19 vaccine, Janssen’s COVID-19 vaccine, and Novavax’s COVID-19 vaccine.

Pfizer Vaccine

During clinical trials, the Pfizer vaccine was proven 95% effective against COVID-19. It’s an intramuscular vaccine given in a patient’s upper arm and patients receive the vaccine in two doses that are given 21 days apart.

Ingredients:

Due to the vaccine being stored at extremely cold temperatures, preservatives are not necessary. Eggs and latex are also not ingredients in the Pfizer COVID-19 vaccine. 

  • Messenger Ribonucleic Acid (mRNA): this acts as the human body’s blueprint in generating the coronavirus antigens that then trigger the immune system to respond and fight back.

  • Lipid Nanoparticle Technology:
    • (4-hydroxybutyl)azanediyl)bis(hexane-6,1-diyl)bis(2-hexyldecanoate): a phospholipid that mimics native phospholipids in the body to help with drug delivery.

    • 2 [(polyethylene glycol)-2000]-N,N-ditetradecylacetamide: a phospholipid linked to polyethylene glycol which aids constipation.

    • 1,2-Distearoyl-sn-glycero-3- phosphocholine: another phospholipid that mimics native phospholipids in the body that compose the cell wall. 

    • Cholesterol: depending on the temperature, this lipid aids in the fluidity or rigidity of the membrane.

  • Potassium Chloride: simple salt of potassium and chloride which helps to stabilize the nanoparticle (found naturally in the body).

  • Monobasic Potassium Phosphate: potassium salt of dihydrogen phosphate which helps to buffer swings in pH levels (found naturally in the body).

  • Sodium Chloride: laboratory-grade table salt to stabilize the nanoparticle.

  • Dibasic Sodium Phosphate Dihydrate: sodium salt of dihydrogen phosphate which helps to buffer swings in pH levels.

  • Sucrose: laboratory-grade table sugar which helps to stabilize nanoparticles during transport.

Note: To learn more about the ingredients and how they function within the Pfizer COVID-19 vaccine, visit this source.

Who Shouldn’t Get the Pfizer Vaccine:

The Pfizer COVID-19 vaccine cannot be given to those under 16 years of age. Furthermore, anyone who has experienced a mild, severe, or immediate reaction to any mRNA vaccine (including the first dose of Pfizer’s COVID-19 vaccine), polyethylene glycol (PEG), and/​or polysorbate, should not get the Pfizer COVID-19 vaccine.

Note: An immediate reaction means experiencing hives, swelling, or wheezing within four hours of receiving an mRNA vaccine.

Common Side Effects:

During clinical trials, most people got mild to moderate side effects while a few had severe side effects. These side effects are prone to start within one to two days after getting vaccinated and should only last a few days at maximum. The side effects related to the Pfizer COVID-19 vaccine include:

  • In Arm:
    • Minor swelling

    • Pain

    • Irritation/​redness

  • Throughout Body (common after the second dose):
    • Chills

    • Mild fever

    • Tiredness

    • Headache

Note: If severe side effects occur or moderate side effects persist for longer than a few days, be sure to contact your doctor.

Moderna Vaccine

During clinical trial testing, the Moderna vaccine was proven 94.1% effective against the coronavirus. The vaccine is an intramuscular shot given in the patient’s upper arm and patients receive the vaccine in two doses that are given 28 days apart.

Ingredients:

No eggs, preservatives, or latex are included in the Moderna COVID-19 vaccine. 

  • Messenger Ribonucleic Acid (mRNA): The only active ingredient in the vaccine, mRNA contains genetic materials that helps trigger the immune system to produce the antibodies that protect a patient if exposed to COVID-19 in the future.

  • Lipids: Helps to coat the mRNA in a slippery exterior so it can better slide inside the body’s cells.
    • SM-102

    • Polyethylene glycol [PEG] 2000 dimyristoyl glycerol [DMG]

    • Cholesterol

    • 1,2-distearoyl-sn-glycero-3-phosphocholine [DSPC]

  • Tromethamine: an acid stabilizer to maintain the vaccine’s stability after it’s manufactured.

  • Tromethamine Hydrochloride: an acid stabilizer to maintain the vaccine’s stability after it’s manufactured.

  • Acetic Acid: an acid that helps to keep the vaccine stable after it’s manufactured.

  • Sodium Acetate: salt that helps to maintain the vaccine’s stability after it’s been produced.

  • Sucrose: sugar that helps to maintain the vaccine’s stability after it’s been produced.

Note: To learn more about the ingredients and how they function within the Moderna COVID-19 vaccine, visit this source.

Who Shouldn’t Get the Moderna Vaccine:

The Moderna COVID-19 vaccine cannot be given to those under 18 years of age. Furthermore, anyone who has experienced a mild, severe, or immediate reaction to any mRNA vaccine (including the first dose of Moderna’s COVID-19 vaccine), polyethylene glycol (PEG), and/​or polysorbate, should not get the Moderna COVID-19 vaccine. 

Note: An immediate reaction means experiencing hives, swelling, or wheezing within four hours of receiving an mRNA vaccine.

Common Side Effects:

During clinical trials, most people got mild to moderate side effects while a few had severe side effects. These side effects are prone to start within one to two days after getting vaccinated and should only last a few days at maximum. The side effects related to Moderna’s COVID-19 vaccine include:

  • In Arm:
    • Minor swelling

    • Pain

    • Irritation/​redness

  • Throughout Body (common after the second dose):
    • Chills

    • Mild fever

    • Tiredness

    • Headache

Note: If severe side effects occur or moderate side effects persist for longer than a few days, be sure to contact your doctor.

Timeline of Vaccine Distribution

Both COVID-19 vaccines started distribution in December with the Center for Disease Control and Prevention (CDC) recommending that the first round of doses go to healthcare personnel and long-term care facility residents. From there, they recommended that frontline essential workers such as firefighters, police officers, U.S. postal workers, etc. and those over 75 years of age should be vaccinated. From this point forward, those aged 65 and older, those over 16 years of age with underlying conditions, and other essential workers such as those in transportation, food service, etc., should be vaccinated. Overall, each state has the authority to design their own vaccination timeline and distribution plan. To learn more about the plan in your state, visit this source.

Vaccinations and Those Over 55 Years of Age

Many questions have been raised surrounding both vaccines’ safety with those 55+ years old and those with comorbid conditions. However, clinical trials proved that COVID-19 vaccine side effects were actually less common and severe within these populations. One study notes that the vaccine is better tolerated in older adults than younger adults” and that its efficacy is similar across all age groups. 

Note: To read personal accounts from those 55 and older on receiving the COVID-19 vaccine, visit this source.

Covid Vaccine Education

Benefits of Getting Vaccinated Against COVID-19

Getting vaccinated for COVID-19 incites three major benefits: protecting yourself from coronavirus, protecting those around you from coronavirus, and aiding the world in ending the coronavirus pandemic.

Protecting Yourself from COVID-19

Clinical trials have determined that COVID-19 vaccines are highly effective at preventing a patient from contracting the coronavirus. The Pfizer vaccine was proven to be 95% effective against the coronavirus during clinical trials while the Moderna vaccine was proven to be 94.1% effective against the coronavirus during clinical trials. Furthermore, past vaccine research shows that if a patient does get infected, being vaccinated helps to protect the patient from growing severely ill. 

Protecting Others from COVID-19

When a person is infected with the coronavirus, they’re considered very contagious. It’s possible for an infected person to spread the disease to their loved ones through respiratory droplets when they breathe, sneeze, cough, etc. In order for each individual to protect themselves and the ones they love from being infected, the CDC emphasizes getting vaccinated. While patients who have already contracted and healed from the coronavirus do have natural immunity, experts are unsure how long this immunity will last. Due to this uncertainty, the CDC is recommending that at the appropriate time, those who can, should be vaccinated.

Ending the Coronavirus Pandemic

The overall goal of the COVID-19 vaccine is to end the current global coronavirus pandemic. Over time, as more and more people are vaccinated, the hope is to grow herd immunity to the virus and have society eventually get back to normal’.

COVID-19 Vaccine FAQs

How were the vaccines developed so quickly?

The COVID-19 vaccines were developed so rapidly due to a variety of factors:

  • Previous research demonstrated the role of the spike protein in coronavirus pathogenesis and displayed evidence that proved the importance of neutralizing that protein in order to reach immunity.

  • Nucleic acid technology has rapidly evolved, allowing vaccines to be created and manufactured much quicker than in years prior.

  • Development activities were able to be conducted in a parallel manner vice sequentially which hastened vaccine testing and manufacturing without putting participants at risk.

Are the COVID-19 vaccines effective against the new coronavirus strain?

The new virus variants are not currently resisting the vaccine. However, experts note that due to the quick rate at which the variants are evolving, it is possible they may eventually mutate into a vaccine-resistant phenotype. If they do continue to evolve, the vaccine may have to be updated in coming years.

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