Executive Summary

  • All three vaccines (Pfizer-BioNTech, Moderna, Johnson & Johnson’s Janssen) were developed based on the Wuhan variant.
  • Although the efficacy rates appeared lower in Johnson & Johnson’s Janssen vaccine, it was tested on a more diverse demographic population (race, more participants with co-existing conditions) and geography (including South America, South Africa), and also at a later date range (closer to the fall rather than spring/summer) such that variants could have been more pervasive.
  • In the studies, it is common (>50%) to experience injection site adverse events such as pain
    • Other common (>~40%) adverse events include fatigue, fever, mylagia (pain in the muscle), headache
    • Allergies were reported during or after studies
  • The only clear advantageous of Johnson & Johnson’s Janssen vaccine is that it administered as one shot versus two for the other vaccines

When the Johnson & Johnson (J&J) vaccine first came out in America, the television news I watched reported a lower efficacy rate (than the Pfizer-BioNTech and Moderna vaccines) but it had been tested for use in a more diverse demographic population and geography. At first glance, it sounded like the J&J vaccine would be better since it might address variants (J&J is advantageous logistically for only being one shot versus two for the other vaccines). Last week, I was asked by readers about the comparison between the vaccines. I’ve neatly summarized the key pieces of information in a table at the bottom (information was extracted from the FDA, NIH and New England Journal of Medicine).

The key notes from the table are as follows:

  • The Pfizer and Moderna vaccine trials included predominantly White and US-based participants, whereas J&J was markedly more diverse in race and country (59% White and just under half are US-based)
  • All three vaccines were developed from the strain found in Wuhan, China around January 2020
  • Adverse events (AE) were similar across vaccines
    • Local AE around the injection site, such as pain, swelling
    • Top systemic AE were fatigue, headache, mylagia (pain in muscles), fever
    • Serious AE were reported but not concluded as vaccine related
    • Allergies were reported during or after study
  • Primary efficacy endpoints were similar: COVID-19 diagnosis determination by PCR test with symptoms 7 or 14 days after last dose
Pfizer-BioNTechModernaJohnson & Johnson – Janssen
 Participants~43k randomized trial; vaccine vs placebo 
~30k randomized trial; vaccine vs placebo
 ~44k randomized trial; vaccine vs placebo
Demographics (race, age, pre-existing conditions)83.1% White, 9.1% Black/African American, 4.3% Asian (28% Hispanic/Latino)

42.2% aged >55

20.5% (page 8) have any Charlson co-morbidities, 35.1% obese (BMI >= 30)
79.5% White, 19.7% Hispanic/Latino

24.8% aged 65+

22.5% (page 17) were at risk for severe COVID-19 at screening (had at least one of the interested risk factors)
59% White, 19% Black/African American (45% Hispanic/Latino)

~34% aged 60+

~40% (page 18) have co-morbidities that risk progression to severe/critical COVID-19
Countries76.7% US, 15.3% ArgentinaUS onlyTop 3 countries: US (~47%), Brazil, South Africa (others: Argentina, Chile, Colombia, Mexico, Peru) 
StrainThe development was initiated on January 10, 2020, when the SARS-CoV-2 genetic sequence was released by the Chinese Center for Disease Control and Prevention and disseminated globally by the GISAID (Global Initiative on Sharing All Influenza Data) initiativeShortly after the SARS-CoV-2
genetic sequence was determined in January 2020, mRNA vaccine was developed by Moderna and the Vaccine Research Center at the National Institute of Allergy and Infectious Diseases (NIAID), within the National Institutes of Health (NIH)
The vaccine was derived from the Wuhan strain (Wuhan 2019; whole genome sequence, NC_045512)

Participant country/variant analysis (71.7% sequenced as of February 12, 2021): US (96.4% Wuhan D614G variant), South Africa (94.5% B.1.351 lineage), Brazil (69.4% P.2 lineage, Wuhan D614G variant 30.6%); B1.1.7 and P.1 lineages were not found
Adverse Events
(local, systemic, serious; allergies)
Safety info from Oct 9 to Nov 14, 2020.

At least 78% reported pain locally (at injection site) after either dose for aged under 56; aged 56+ was at least 66%

At least 42% or 48% reported headache or fatigue respectively after either dose for aged under 56; aged 56+ was at least 25% or 34% respectively

Unsolicited adverse events up to 30 days after vaccine: 0.4% percent in under aged 56 reported serious adverse events; aged 56+ was 0.8%; non-serious was 29.3% n under aged 56; aged 56+ was 23.8%

Allergic reactions were voluntarily reported post-authorization/trial
86% reported pain at injection site.

Top systemic were fatigue, headache, myalgia (pain in muscles). 54.9% of any event after first dose and 79.4% after second.

23.9% of participants reported unsolicited adverse events 28 days following each vaccine (as of November 25, 2020)

Allergic reactions are possible
Solicited local (where injection occurred): 59.6% reported pain aged 18-59; 33.3% over aged 60

Top systemic (headache, fever, myalgia – pain in muscles): 39-44% aged 18-59; 24-30% over aged 60

Unsolicited 28 days after vaccination: none with causal relation to J&J (13.1% versus 12% in vaccine versus placebo group) as of January 22, 2021.

Allergic reactions were reported during study
Primary Endpoint  & Efficacy95%; Primary efficacy analysis is no infection 7 days after 2nd dose without prior infection (COVID-19 determined by RT-PCR test and at least 1 related symptom)94.1%; Primary efficacy is positive RT-PCR test and at least two systemic or at least on respiratory symptom 14 days after second injectionEnd points are moderate to severe/critical COVID-19 using PCR test and symptoms at 14 and 28 days after vaccination (66.9%, 66.1% efficacies), for severe/critical (76.7%, 85.4% efficacies). Percentages varied by country (lowest rates in South Africa).


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