Currently, four COVID-19 vaccines are being administered throughout the United States. The vaccines are Pfizer, Moderna, Johnson & Johnson (J&J) Janssen, and Novavax vaccine. All four vaccines are proven to be effective at preventing severe illness and death from COVID-19 

All vaccines train your immune system to help fight off the COVID-19 virus if you come in contact with it. There are some differences between the vaccine types, such as mRNA vs. viral vector. Overall they all work to accomplish the same task which is keeping you safe from COVID-19. 

How Many Types of COVID-19 Vaccines Are There?  

Currently there are three different types of COVID-19 vaccines available. The Pfizer and Moderna vaccines are both mRNA vaccines, the Johnson & Johnson vaccine is a viral vector vaccine, and Novavax is a protein subnuit vaccine. 

What is a mRNA vaccine?

mRNA vaccine teaches our cells to make a protein which triggers an immune response in the body. The immune responses results in the production of antibodies which help protect us we ever come into contact with the real virus. 

What is a protein subnuit vaccine?

A protein subnuit vaccine contains pieces (proteins) of the virus that cause COVID-19. These virus pieces are the spike protein. The vaccine also contains another ingredient called an adjuvant that helps the immune system respond to that spike protein in the future. 

What is a viral vector vaccine?

viral vector vaccine uses a different virus as vector which deliver’s instruction’s (in the form of a gene) to our cells. The gene then instructs cells to make a SARS-CoV-2 antigen (spike protein). The antigen triggers production of antibodies and a resulting immune response. These antibodies will help protect us if the virus ever enters our bodies

Vaccine Dosages & Age Eligibilities




Johnson & Johnson


Dosage for Initial Series

(guidance based off the ages 18+)

2 doses given 21 days apart (3 weeks) 2 doses given 28 days apart (4 weeks) 1 dose at one time 2 doses given given 21 days apart (3 weeks)
Age for Initial Series
Ages 6 months+* Ages 6 months+* Ages 18+ Ages 12+*
Booster Shot Dosage

(guidance based off the ages 18+)

2 months after initial series OR last booster. 2 months after initial series OR last booster. 2 months after initial series. 2 months after initial series.
Age for Booster Shot
Ages 6 months+* Ages 6 months+* Ages 18+ Ages 12+*
Additional Information

mRNA bivalent boosters are recommended in most situations.

mRNA bivalent boosters are recommended in most situations. Monovalent boosters are available in limited situations. Monovalent boosters are available in limited situations.

*For additional COVID-19 vaccine guidance for those under 18 should visit the CDC COVID vaccine resource page.

For the Pfizer, Moderna, and Novavax vaccines to be most effective you must receive both doses. After you receive your dose of J&J or both doses of the Moderna, Pfizer or Novavax vaccine, it takes two weeks for your body to build protection against the virus. 

All the vaccines are shown to be effective at preventing severe illness from COVID-19. We strongly encourage you to be up to date on your COVID-19 vaccines.

What Are The Side Effects?

It’s normal to experience side effects after any vaccine. It is a good sign to experience some side effects because this means that your body is working on creating an immune response to COVID-19. Everyone responds differently to vaccines, some have mild or no side effects. 

All three COVID-19 vaccines have similar post-vaccination side effects that typically a few days. Side effects after a second shot may be more intense than the the ones experienced after the first shot. Side effects from booster doses are similar to those after the of the initial side effects and most were mild to moderate.

Common Side Effects

  • Pain, swelling or redness around vaccination site
  • Fatigue and tiredness
  • Fever or chills
  • Headache
  • Muscle pain or aches
  • Nausea

What Are Rare Side Effects? 

Although these side effects are very rare, they can happen. Any health problem that happens after a vaccine is considered an adverse event. An adverse event can be caused by the vaccine or can be a coincidental event not related to the vaccine.

If you experience an adverse side effect, please contact your doctor. 


Anaphylaxis is very rare after receiving a COVID-19 vaccine. It is a severe allergic reaction to a vaccine, such as hives, difficulty breathing, or signification swelling. Anaphylaxis can happen after any and all vaccines.

This happens shortly after the vaccine is administered. This is why after receiving your initial series or when mixing & matching booster doses you may be asked to wait 15 minutes for observation.

Thrombosis with Thrombocytopenia Syndrome (TTS)

TTS is very rare after receiving a COVID-19 vaccine. It is a blood clotting problem that was primarily experienced by females 18-49 after receiving the J&J vaccine. Side effects occur 7-10 days after receiving the vaccine and include bleeding, severe headache, or stomach pain.

You may remember when J&J first became available and there was a small number of females who experienced blood clotting. This resulted in J&J distribution being stopped for several weeks for them to investigate further.


Myocarditis is very rare after receiving a COVID-19 vaccine. It is typically experienced by males, 16-39, who received an mRNA vaccine. Myocarditis is inflammation around the heart and symptoms appeared 1-3 days after the vaccine and include: chest pain, shortness of breath, and irregular heartbeat.

Some studies have shown that waiting longer than the recommended 21 or 28 days in between the initial series of mRNA vaccines decreased the chances of this adverse event. If you have concerns, please talk with your health care provider.

Guillain-Barré Syndrome (GBS)

GBS is very rare after receiving a COVID-19 vaccine. This typically occurs in males 50-65 after receiving J&J. GBS is a rare disorder where the body’s immune system damages nerve cells causing muscle weakness. Symptoms start 2-6 weeks after the vaccine and include growing weakness from feet or legs moving upwards.

If you prefer one vaccine type over the other, you may need to call around to the local clinics to see which types they have on hand.

If you have any questions or concerns, please contact the Ask-A-Nurse message line at 507.457.2292 or by email at 

Once you receive a vaccine, please fill out the self-report form.