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December 18th, 2020- The Moderna Vaccine


Last week the FDA approved the Pfizer vaccine, which was the topic of our last newsletter. If you would like to read more about its safety and trial data, you can see our last newsletter here. This week we take a closer look at the Moderna vaccine.


Moderna Vaccine

The FDA published its briefing document Tuesday in anticipation of the independent vaccine advisory committee meeting on Dec 17th. The committee met yesterday and recommended approval of the vaccine. The meeting documents included an endorsement from the FDA staff. Research data from the Moderna vaccine trials included 30,420 enrolled subjects, 15208 of who received the vaccine. The summary information showed 11 cases of COVID-19 in those who received the vaccine and 185 in those who did not, showing an efficacy of 94.1%. Of those who became ill, there were no severe cases in the vaccine group and 30 severe cases in the placebo group. Efficacy was slightly less in those 65 years or older at 84.6%

Much like the Pfizer vaccine, the Moderna vaccine consists of 2 doses given intramuscularly, 4 weeks apart. The vaccine is supplied as a multi-dose vial (10 doses) and can be kept in a standard freezer, unlike the Pfizer vaccine which requires ultra cold storage. The Moderna vaccine does not contain a preservative.

If the vaccine is approved under emergency authorization, which anticipated later today, the emergency use authorization (EUA) is not the same as approval and requires manufacturers to continue to collect data on safety from the study population for a period of 24 months. In addition, monitoring side effects of the vaccine will occur through the standard national methods for vaccine related side effects.


Interestingly, there were less side effects reported in patients 65 years of age and older than in younger patients, after the second dose. Safety data from the FDA report noted the following:

  • The most common adverse reactions were injection site pain (91.6%), fatigue (68.5%), headache (63.0%), muscle pain (59.6%), joint pain (44.8%), and chills (43.4%);
  • Lymphadenopathy was reported in 173 participants (1.1%) in the vaccine group and 95 participants (0.63%) in the placebo group. Lymphadenopathy (axillary swelling and tenderness of the vaccination arm) was a solicited adverse reaction observed after any dose in 21.4% of vaccine recipients <65 years of age and in 12.4% of vaccine recipients ≥65 years of age, as compared with 7.5% and 5.8% of placebo recipients in those age groups, respectively
  • There were slightly more hypersensitivity events in vaccine recipients (1.5%) versus the placebo group (1.1%) . There were no anaphylactic or severe hypersensitivity reactions immediately after receiving the vaccine.
  • Bell’s Palsy was reported in 3 cases in the vaccine group and 1 in the placebo group. These represent insufficient numbers to determine a causal relationship. Further monitoring was recommended.
  • Serious adverse events occurred in1% of both groups
    • Vaccine group: myocardial infarction (heart attacks) 0.03%, cholecystitis (gallbladder infection) 0.02%, and nephrolithiasis (kidney stones) 0.02%, no causal relationship due to low numbers.
    • Placebo group: COVID-19 (0.1%), pneumonia (0.05%) and pulmonary embolism (0.03%).
  • Deaths – As of December 3, 2020, 13 deaths were reported (6 vaccine, 7 placebo). These deaths represent events and rates that occur in the general population of individuals in these age groups.
    • Vaccine group: Two deaths were due to heart disease in participants >75 years of age with pre-existing cardiac disease. Another two vaccine recipients were found deceased at home, and the cause of these deaths is uncertain. One case was a 72-year-old vaccine recipient with multiple medical problems who was hospitalized due to an infected kidney stone and died. One vaccine recipient died of suicide 21 days after dose one.
    • Placebo group: Recipients died from myocardial infarction (n=3), intra-abdominal perforation (n=1), systemic inflammatory response syndrome in the setting of known malignancy (n=1), COVID-19 (n=1), and unknown cause (n=1).

Populations Studied

  • Populations studied in this vaccine trial included:
    • 47.4% females
    • 25.3% individuals ≥65 years of age.
    • There were 36.5% of participants considered as representing communities of color with 9.7% African American, 4.7% Asian, and <3% from other racial groups; 20% of participants were Hispanic/Latino.
    • A majority of the participants (82%) were considered at occupational risk for SARS-CoV-2 exposure, with 25.4% of participants being healthcare workers.
    • At least one high-risk condition for severe COVID-19 was present in 22.3% of participants, and 4% of participants had two or more. The risk factors were conditions that placed an individual at increased risk for severe complications of COVID-19 based on CDC recommendations. These conditions included the following:
      • Chronic lung disease (e.g., emphysema and chronic bronchitis), idiopathic pulmonary fibrosis and cystic fibrosis) or moderate to severe asthma
      • Significant cardiac disease (e.g., heart failure, coronary artery disease, congenital heart disease, cardiomyopathies, and pulmonary hypertension)
      • Severe obesity (body mass index ≥40 kg/m2)
      • Diabetes (Type 1, Type 2 or gestational)
      • Liver disease
      • HIV infection

The table below shows the numbers of each category included in the vaccine trial.

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In addition, much like the Pfizer vaccine, there was evidence for immunity beginning as soon as 12 days after the first vaccine dose.

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