COVID-19 vaccine, mRNA-Moderna (Investigational)

Brand and Other Names:mRNA-1273 (Moderna)
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Dosing & Uses


Dosage Forms & Strengths

injection, suspension

  • Primary series or third dose for immunocompromised individuals: 100mcg/0.5mL
  • Booster: 50mcg/0.25mL
  • 2 multiple-dose vial sizes (5.5-mL, 7.5-mL)

COVID-19 Disease Prevention

December 18, 2020: Emergency use authorization (EUA) issued by FDA for active immunization to prevent COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in individuals aged ≥18 years

2-dose primary series: 0.5 mL (100 mcg) IM x2 doses administered 1 month apart

Third dose for severely immunocompromised individuals

  • August 12, 2021: EUA reauthorized to allow a third dose (0.5 mL [100 mcg]) administered at least 28 days following the 2-dose regimen of an mRNA vaccine in individuals who have undergone solid organ transplantation or who are diagnosed with conditions that are considered to have an equivalent level of immunocompromise

Homologous booster dose

  • The EUA was amended to allow a single booster dose to be administered at least 5 months after completing the primary series for all adults aged ≥18 years
  • Booster dose: 0.25 mL (50 mcg) IM

Heterologous boosters

  • The EUA allows use of each of the available COVID-19 vaccines as a heterologous (or “mix and match”) booster dose following completion of primary vaccination with a different available COVID-19 vaccine
  • 0.25 mL (50 mcg) IM may be administered as a heterologous booster dose following completion of primary vaccination with another authorized or approved COVID-19 vaccine
  • Eligible population(s) and dosing interval are the same as those authorized for a booster dose of the vaccine used for primary vaccination (ie, at least 5 months after Comirnaty [Pfizer] vaccine or 2 months after single-dose Janssen [Johnson & Johnson] vaccine)

Dosing Considerations

Limitations of effectiveness: May not protect all vaccine recipients

<18 years: Safety and efficacy not established


Adverse Effects

VAERS Reporting

Mandatory for vaccination providers to report to the vaccine adverse events reporting system (VAERS) all vaccine administration errors, serious adverse events, multisystem inflammatory syndrome, and hospitalized or fatal cases of COVID-19 following vaccination


Aged 18-64 years

  • Dose 1
    • Injection site pain (86.9%)
    • Fatigue (38.4%)
    • Headache (35.3%)
    • Myalgia (23.7%)
    • Arthralgia (16.6%)
    • Axillary swelling/tenderness (11.6%)
  • Dose 2
    • Injection site pain (89.9%)
    • Fatigue (67.6%)
    • Headache (62.8%)
    • Myalgia (61.6%)
    • Chills (48.6%)
    • Arthralgia (45.5%)
    • Nausea/vomiting (21.4%)
    • Fever (17.4%)
    • Axillary swelling/tenderness (16.2%)
    • Injection site swelling ≥25mm (12.6%)
    • Myalgia, grade 3 (10.1%)
    • Fatigue, grade 3 (10.7%)

Aged ≥65 years

  • Dose 1
    • Injection site pain (74%)
    • Fatigue (33.3%)
    • Headache (24.5%)
    • Myalgia (19.7%)
    • Arthralgia (16.4%)
  • Dose 2
    • Injection site pain (83.2%)
    • Fatigue (58.3%)
    • Myalgia (47.1%)
    • Headache (46.2%)
    • Arthralgia (35%)
    • Chills (30.9%)
    • Nausea/vomiting (11.8%)
    • Injection site swelling ≥25mm (10.8%)


Aged 18-64 years

  • Dose 1
    • Nausea/vomiting (9.4%)
    • Chills (9.2%)
    • Injection site swelling ≥25mm (6.7%)
    • Injection site pain, grade 3 (3.2%)
    • Injection site erythema ≥25mm (3%)
    • Headache, grade 3 (1.9%)
    • Fatigue, grade 3 (1.1%)
  • Dose 2
    • Injection site erythema ≥25mm (8.9%)
    • Arthralgia, grade 3 (5.9%)
    • Headache, grade 3 (5%)
    • Injection site pain, grade 3 (4.6%)
    • Injection site erythema, grade 3 (1.9%)
    • Injection site swelling, grade 3 (1.7%)
    • Fever, grade 3 (1.7%)
    • Chills, grade 3 (1.5%)

Aged ≥65 years

  • Dose 1
    • Axillary swelling/tenderness (6.1%)
    • Chills (5.4%)
    • Nausea/vomiting (5.2%)
    • Injection site swelling ≥25mm (4.4%)
    • Injection site erythema ≥25mm (2.3%)
    • Headache, grade 3 (1.4%)
    • Pain, grade 3 (1.3%)
  • Dose 2
    • Fever (10%)
    • Axillary swelling/tenderness (8.5%)
    • Injection site erythema ≥25mm (7.5%)
    • Fatigue, grade 3 (6.9%)
    • Myalgia, grade 3 (5.6%)
    • Arthralgia, grade 3 (3.3%)
    • Headache, grade 3 (2.9%)
    • Pain, grade 3 (2.7%)
    • Injection site erythema, grade 3 (2.1%)
    • Injection site swelling, grade 3 (2%)

Post Authorization Experience

Cardiac disorders: Myocarditis, pericarditis

Immune system disorders: Anaphylaxis

Unsolicited Adverse Events During Clinical Trial

Lymphadenopathy related events: 1.1% vaccine; 0.6% placebo

Hypersensitivity: 1.5% vaccine; 1.1% placebo

Delayed injection site reactions >7 days postinjection: 1.2% vaccine; 0.4% placebo

Bell palsy: 3 cases vaccine; 1 case placebo (data insufficient to determine causal relationship with vaccine)




Known history of severe allergic reaction (eg, anaphylaxis) to any component in vaccine

CDC listed contraindications

  • CDC has listed the following contraindications
  • Severe allergic reaction after previously receiving mRNA COVID-19 vaccine or its components
  • Allergic reaction (of any severity) immediately after receiving mRNA COVID-19 vaccine or its components, including polyethylene glycol (PEG)
  • Immediate allergic reaction (of any severity) to polysorbate (due to potential cross-reactive hypersensitivity with the vaccine ingredient PEG)


Immunocompromised persons, including individuals receiving immunosuppressant therapy, may have diminished immune response to the vaccine

Vaccine may not protect all vaccine recipients

Allergic reactions

Appropriate medical treatment used to manage immediate allergic reactions must be immediately available following vaccination

Do not administer second dose to anyone experiencing a severe reaction (ie, requiring epinephrine or hospitalization) to the first dose

Individuals with histories of severe allergic reaction to vaccines should consult their doctors about the COVID-19 vaccine

People with severe allergies to food, pets, latex, oral medications, or environmental conditions may be vaccinated according to interim CDC clinical considerations for mRNA COVID-19 vaccines

  • Vaccine Adverse Event Reporting System (VAERS)
    • December 21, 2020 – January 10, 2021: 10 cases of anaphylaxis detected after administration of of 4,041,396 first doses (2.5 cases per million doses) reported in MMWR
    • 90% of these occurred within 15 minutes of vaccination
    • 9 of 10 anaphylaxis cases occurred in people with a known history of allergies or allergic reactions (eg, medications, foods, contrast media0, including 5 with prior anaphylactic reactions, none of which was associated with receipt of a vaccine

Myocarditis and pericarditis

  • Reports of adverse events following use of mRNA COVID-19 vaccines suggest increased risks of myocarditis and pericarditis, particularly following the second dose
  • Symptom onset is typically within a few days after vaccine administration
  • Instruct patients to seek immediate medical attention if they experience chest pain, shortness of breath, of feelings of a fast-beating, fluttering, or pounding heart after receiving the vaccine
  • Available data from short-term follow-up (as of June 2021) suggest that most individuals have had resolution of symptoms, but information is not yet available about potential long-term sequelae
  • The decision to administer an mRNA vaccine to individuals with history of myocarditis or pericarditis should take into account the individual’s clinical circumstances
  • The CDC has published clinical considerations relevant to myocarditis and pericarditis with mRNA COVID-19 vaccines

Drug interaction overview

  • Data are not available to assess concomitant administration with other vaccines

Pregnancy & Lactation


Data are insufficient to inform of vaccine-associated risks in pregnancy

Pregnancy registry: Women who are vaccinated with Moderna COVID-19 vaccine during pregnancy are encouraged to enroll in the registry by calling 1-866-MODERNA (1-866-663-3762)

A smartphone app, v-safe, is also available to report adverse effects to the CDC following vaccination with a COVID-19 vaccine

CDC guidelines for vaccination of pregnant or lactating women

Animal data

  • Vaccine administered IM to female rats 28 and 14 days prior to mating, and on gestation days 1 and 13
  • No vaccine-related adverse effects on female fertility, fetal development, or postnatal development were reported


Data are not available to assess effects on breastfed infants or on milk production/excretion

Pregnancy Categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.



Mechanism of Action

Nucleoside-modified messenger RNA (modRNA) encoding the viral spike (S) glycoprotein of SARS-CoV-2; formulated in lipid particles, which enable delivery of RNA into host cells to allow expression of the SARS-CoV-2 S antigen

Elicits an immune response to the S antigen, which protects against COVID-19



IM Preparation

Thaw frozen suspension before administering

Thaw in refrigerator: 2-8ºC (36-46ºF) for 2.5 hr (5.5-mL vial) or 3 hr (7.5-mL vial); after thawing, let vial stand at room temperature for 15 minutes before administering

Alternatively, thaw at room temperature of 15-25ºC (59-77ºF) for 1 hr (5.5-mL vial) or 1.5 hr (7.5-mL vial)

After thawing, do not refreeze

Do not shake; swirl vial gently after thawing and between each withdrawal

Do not dilute

Suspension is white to off-white and may contain white or translucent product-related particulates

Visually inspect for other particulate matter and/or discoloration administration; if either of these conditions exists, do not administer

Syringes and needles

  • Each primary series dose must contain 0.5 mL
  • Each booster dose must contain 0.25 mL
  • Primary series doses of 0.5 mL and booster doses of 0.25 mL may be extracted from either vial presentation, preferentially using low dead-volume syringes and/or needles
  • Primary series doses
    • Depending on syringes and needles used for each dose, there may be insufficient volume to extract >10 doses from the maximum of 11 doses vial and >13 doses from the maximum of 15 doses vial
    • Do not exceed 20 doses when extracting only booster doses or a combination of primary series and booster doses; do NOT puncture vial stopper >20 times
  • Irrespective of syringe and needle type
    • If vial has been punctured 20 times, discard vial and contents
    • If amount remaining in vial cannot provide a full dose of 0.5 mL or 0.25 mL, discard vial and contents; do not pool excess vaccine from multiple vials
    • Pierce vial at different site each time drawing dose

IM Administration

For IM injection only


Does not contain preservatives

Vial stoppers are not made with natural rubber latex

Unopened vials

Store in original carton to minimize exposure to room light

  • Frozen
    • Store frozen at -50ºC to -15ºC (-58ºF to 5ºF)
    • Do not store on dry ice or below -50ºC (-58ºF); dry ice may subject vials to temperatures colder than -50ºC (-58ºF)
  • Refrigerated
    • Can be refrigerated at 2-8ºC (36-46ºF) for up to 30 days before first use
    • Do not refreeze
  • Controlled room temperature
    • May be stored at 8-25ºC (46-77ºF) for up to 24 hr
    • Do not refreeze

After first dose withdrawn from vial

  • Store refrigerated or at room temperature at 2-25ºC (36-77ºF)
  • Discard vial after 12 hr
  • Thawed vials can be handled in room light conditions
  • Do not refreeze

Transportation of thawed vials

  • If unable to transport at -50ºC to -15ºC (-58ºF to 5ºF), available data support transportation for up to 12 hr at 2-8ºC (35-46ºF) when shipped using shipping containers qualified to maintain this temperature under routine road and air transport conditions with shaking and vibration minimized
  • After shipping, do not refreeze vials; store refrigerated at 2-8ºC (35-46ºF) until use


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