Drawing a comparison between the three COVID-19 vaccines authorized in the U.S. is a bit difficult due to lack of head-to-head trails. Instead, let’s look at the some of the important characteristics of each vaccine.

Vaccine Name: Ad26.COV2.S

Company: Johnson & Johnson/Janssen

Efficacy: 66% globally while its 72% in the U.S. against moderate-to-severe disease. It is 85% effective against severe disease, 28 days after a single dosage.

Moderate illness was described as confirmed COVID-19 positive test in addition to one more of the following:

• Evidence of pneumonia

• Shortness of breath or

• Abnormal blood oxygen saturation above 93%,

• Deep vein thrombosis

• Respiratory rate is abnormal (≥20)

Or

• Two or more symptoms that suggest COVID-19.

Severe illness was described as a confirmed positive case of COVID-19 test in addition to one or more of these:

• Admission to an intensive care unit

• Shock

• Respiratory failure

• Organ failure or death

• Signs consistent with severe systematic illness.

Dosing Schedule: One dose (two dosage schedule under evaluation)

Mechanism of Action: Adenovirus vector vaccine

This vaccine by Johnson & Johnson used a technology called “viral vector”. It uses a harmless, inactivated cold virus to activate the body’s immune response to recognize and learn to attack the COVID-19 virus.

Side Effects: 

• Headache (39%)

• Fatigue (38%)

• Myalgia (33%)

• Nausea (14%) and

• Fever (9%).

Trial Participants: 43,783 people age 18 and up

Storage: Stable for 2 years at -4ºF (-20ºC).

Though it can be stored for at least 3 months at typical refrigeration temperatures of 36ºF to 46ºF.

Number of Doses Contracted by the U.S.: 100 million

 

2. Vaccine Name: BNT162b2

Company:  Pfizer/BioNTech

Efficacy: 95% at least 7 days after dose 2

Illness is described as being confirmed positive COVID-19 test and atleast one of these symptoms:

• New or increased cough

• Fever

• Sore throat

• New or increased shortness of breath

• Chills

• New or increased muscle pain

• New loss of taste or smell

• Diarrhea or vomiting

Mechanism of Action: mRNA vaccine

This vaccine works by using genetic material to trigger the body to create a protein from the virus and this promotes an immune system response to identify the virus and learn to attack the virus.

Dosing Schedule: Two doses, 21 days apart (30 μg/dose)

Side Effects: Most common side effects are:

• Headache and

• Fatigue after both doses.

Both these symptoms become prominent after the second dose.  

These were comparatively mild for participants over 55 compared to those who were between the ages of 16 to 55.

For the latter group these were the side effects after two doses:

• Fatigue (59%)

• Headache (52%)

Trial Participants: 43,548 people age 16 and up

Storage: Ultra-cold freezer required:

 -112ºF to -76ºF for up to 6 months,

FDA has recently to let storage of frozen, undiluted vials at standard pharmacy freezer temperatures between:

13ºF and 5ºF for up to 2 weeks.

Number of Doses Contracted by the U.S.: 300 million

3. Vaccine Name: mRNA-1273

Company: Moderna

Efficacy: 94.1% at least 14 days after dose 2

Illness was described as confirmed positive COVID-19 test and atleast two of these symptoms:

• Fever

• Myalgia

• Headache

• Chills

• Sore throat

• New olfactory or taste disorder;

or at least one respiratory sign or symptom including

• Cough

• Clinical or radiographic evidence of pneumonia

• Shortness of breath

Dosing Schedule: Two doses, 28 days apart (100 μg/dose)

Mechanism of Action: mRNA vaccine

The Moderna COVID-19 Vaccine works by using genetic material (messenger-RNA) to trigger the body to create a protein from the virus thus promoting an immune system response to identify the virus and learn to attack the virus.

Side Effects: 

Overall side effects or reactions were:

• Fever

• Chills

• Headache, and

• Myalgia, were observed in 60% of participants after the first dose.

While in 80% of participants after the second dose.

Trial Participants: 30,420 people age 18 and up

Storage: Frozen between

-13ºF to 5ºF

Can be stored refrigerated from

36ºF to 46ºF for up to 30 days prior to first use.

Number of Doses Contracted by the U.S.: 300 million

MedPage Today shares these comparisons.