COVID Vaccine Types

By Dr. Katie Kuehner, D.O. Urgent Care Medical Director

Vaccination is in full swing this spring.

Hey, all!  This week we are going to recap all three vaccine options.  Which, actually – spoiler alert – is not controversial at all. 

As a reminder, experts still universally agree that the best vaccine is the one you can get.  Let me repeat myself….  The best vaccine is the one that you can get.

We are currently scheduling vaccine appointments. Check out details here.

All 3 vaccines, Moderna, Pfizer, and J&J:

  1. Reduce symptomatic disease
  2. Prevent hospitalization
  3. Prevent death
  4. Are starting to show data that they can reduce asymptomatic spread
    1. Hello, getting our collective lives back!

The nitty gritty on all 3:

  1. Moderna
    • This is the vaccine Exemplar Care has been allocated.
    • Approved for 18 and older
    • Stored between -25*C to -15*C *(-13*F to 5*F)
    • 2 shots
      • Shots are 4 weeks apart plus 2w for full immunity = 6 weeks total
    • mRNA
      • Genetic code to make the spike protein and activate the immune system
    • Efficacy
      • 80.2% effective after the 1st dose against symptomatic COVID
      • 94.1% effective after the 2nd dose against symptomatic COVID
      • 100% effective against hospitalizations
      • 100% effective against death
    • Trials
      • Initial trials were done earlier and did not include any known variants
        • Currently being found to be effective against UK strain but not sure on other variants
      • Has completed animal trials for safety in pregnancy and lactating women
        • Will be starting human trials
      • Currently studying for approval in 12-17 year olds
  2. Pfizer
    • Approved for 16 and older
    • Needs a super freezer
      • Storage temps between -80*C and -60*C (-112*F to -76*F) 
        • This makes it harder to distribute
    • 2 shots
      • Shots are 3 weeks apart plus 2 weeks for full immunity = 5 weeks total
    • mRNA
      • Genetic code to make the spike protein and activate the immune system
    • Efficacy
      • 46% effective after 1st dose against symptomatic COVID
      • 95% effective after the 2nd dose against symptomatic COVID
      • 100% effective against hospitalization
      • 100% effective against death
    • Trials
      • Initial trials were done earlier and did not include any known variants
        • Currently being found to be effective against UK strain but not sure on other variants
      • Currently studying for approval in pregnancy and lactating women
        • Did not do animal trials
      • Currently testing in the 12-16 age group
  3. J&J
    • Approved for 18 and older.
    • Can be kept in a normal refrigerator, between 2*C and 8*C (36*F to 46*F)
      •  Easier to store and distribute
    • Only one dose
      • One shot plus 4 weeks for full immunity to develop = 4 weeks total
    • Viral Vector Vaccine
      • Another virus (adenovirus – virus for the common cold) is used to transport the protein that triggers the immune system
        • Same science used for the EBOLA vaccine
    • Efficacy after 4 weeks
      • 72% effective against moderate disease
      • 85% effective against severe disease
      • 100% effective against hospitalization
      • 100% effective against death
    • Trials
      • Trials included the UK and South African variants as well as other variants, so we know it works against them
      • A two-dose regimen is being tested
      • There are plans for testing in the 0-15 age group, 15-18 age group, pregnant women, and lactating women, but these trials haven’t started yet
        • However, other viral vector vaccines are already considered safe in all of these age groups 

With Pfizer or Moderna, if you missed your second one, contact a vaccination center.  You have to get the same kind (Pfizer or Moderna) but it doesn’t matter where or when, get that second shot.

Not feeling well after the vaccine is normal.  It is the immune system working.  It is not a sign that you are sick or that the vaccines are not safe.  

Get vaccinated even if you have had COVID, just not while you are actively sick.

As for a difference in the efficacy between the three, it’s hard to say.  No one has done a head-to-head trial.  Yet.  It is important to remember that J&J’s studies were done later and against more variants.  All of that being said, all vaccine types will probably require boosters as more variants develop.

The US is also likely to approve the Oxford-AstraZeneca vaccine.  It is another viral vector vaccine, much like the J&J.  However, unlike the J&J, it is a two-shot series.  It is 62% effective after one vaccination and 82% effective after the second dose with the same 100% effectiveness in preventing hospitalization and death.  Trials in Europe are investigating a potential link to blood clots because there have been less than 40 confirmed pulmonary emboli, or blood clots in the lungs.  However, researchers are not concerned.  They are noting that less than 40 cases out of the millions already vaccinated is lower than the incidence of this type of blood clots in the general population.  It is expected that this vaccine will get the green light as an option soon.

So, when making the decision on what to do regarding vaccination, the answer is to get the shot or shots, whatever type you have access to.  The best vaccine is the one you can get.

Exemplar Care is an approved vaccination site. 
We are currently getting the Moderna vaccine. Vaccine information is available online.  Vaccinating is done based on IDPH recommendations for eligible groups (
Eligibility | Vaccinate Iowa).

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