COVID 19 MRNA Vaccine (Nucleoside Modified)
Pronunciation: (koh-MEER-nah-tee).
- Generic name
- COVID-19 mRNA vaccine (nucleoside-modified)
- Brand names
- BNT162b2, Comirnaty, Pfizer-BioNTech COVID-19 Vaccine
- Drug class
- Vaccine (mRNA-based)
Availability and supply rules vary by country
Trade names by country:
Australia: · Full directory
What COVID-19 mRNA vaccine (nucleoside-modified) is and how it works
Uses, formulations, monitoring, and supply rules can differ by patient, product, and country. Follow the exact local product information and professional advice.
Mechanism of action: how COVID-19 mRNA vaccine (nucleoside-modified) works
Comirnaty is an mRNA vaccine that encodes the full-length spike (S) protein of SARS-CoV-2. After intramuscular injection, the mRNA is taken up by host cells, which then transiently express the spike protein. This triggers both humoral (antibody-mediated) and cellular (T-cell mediated) immune responses, leading to the development of immunity against COVID-19. (2)
What COVID-19 mRNA vaccine (nucleoside-modified) is used for
COVID-19 prevention
Current FDA-approved formula authorization is restricted to people 65 and older, and people 5 through 64 with at least one underlying condition that increases risk of severe COVID-19 — not a general recommendation for all ages/risk levels. (2)
Before taking COVID-19 mRNA vaccine (nucleoside-modified)
Do not take / not appropriate for
- a history of severe allergic reaction (anaphylaxis) to a previous dose or any component of the vaccine. (Contraindication)
- Vaccination should be deferred in individuals with acute febrile illness. (Contraindication)
Tell your clinician about
(2)How to take COVID-19 mRNA vaccine (nucleoside-modified)
- General Instructions: Comirnaty is administered as an intramuscular injection by a healthcare professional. The current FDA-approved formula is restricted to people 65 and older, and people 5 through 64 with at least one underlying condition that increases the risk of severe COVID-19; it is a single dose for this current formula, not the multi-dose primary series required by earlier formulations.. Adult Dosing: For eligible adults and adolescents (12 years and older): a single 0.3 mL (30 mcg) dose; if previously vaccinated with any COVID-19 vaccine, given at least 2 months after the last dose.. Pediatric Dosing: For eligible children 5 through 11 years: a single 0.3 mL (10 mcg, single-dose vial) dose, with the same 2-month interval rule if previously vaccinated. The current approved formula is not authorized for children under 5.. Administration: Given as an injection into the muscle of the upper arm (deltoid) or thigh (for young children).. When To Stop: If you experience a severe allergic reaction, seek immediate medical attention; let the healthcare provider assessing you determine whether you should receive further doses.. Storage: Store vials in a freezer at -90°C to -60°C (-130°F to -76°F) until ready for use. Thawed vials can be stored in a refrigerator (2°C to 8°C) for up to 10 weeks. Do not refreeze. Follow local storage guidelines.
- This page does not provide a dose calculator. Dosing must follow the prescriber, pharmacist, or product label.
Procedures and treatment changes
Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (2)
Missed dose
If you miss a scheduled dose, contact your healthcare provider as soon as possible to reschedule. Do not double up doses. The next dose should be given as soon as feasible, following recommended intervals.
Overdose
There is no specific antidote for vaccine overdose. If more than the recommended dose is administered, monitor for side effects and provide supportive care as needed. Seek medical attention if severe reactions occur. (2)
Side effects
Side effects and their urgency vary; report severe, persistent, or concerning symptoms to a healthcare professional.
Pain at injection site
Incidence: Reported in the clinician-authored database; frequency not established
Fatigue
Incidence: Reported in the clinician-authored database; frequency not established
Headache
Incidence: Reported in the clinician-authored database; frequency not established
Muscle pain
Incidence: Reported in the clinician-authored database; frequency not established
Chills
Incidence: Reported in the clinician-authored database; frequency not established
Fever
Incidence: Reported in the clinician-authored database; frequency not established
Myocarditis
Incidence: Reported in the clinician-authored database; frequency not established
Pericarditis
Incidence: Reported in the clinician-authored database; frequency not established
Serious warnings
Severe allergic reactions (anaphylaxis) can occur but are rare — serious
Symptoms: Severe allergic reactions (anaphylaxis) can occur but are rare. Myocarditis and pericarditis have been reported, especially in young males. Immunocompromised individuals may have a reduced immune response. Delay vaccination if you have a moderate or severe acute illness. Report any unusual or persistent symptoms to your healthcare provider.
Action: Follow the urgency stated and seek prompt or emergency care when indicated. (2)
The FDA label reports that safety analyses have shown increased risks of myocarditis and pericarditis after Comirnaty, with symptom onset typically within the first week after vaccination — serious
Symptoms: The FDA label reports that safety analyses have shown increased risks of myocarditis and pericarditis after Comirnaty, with symptom onset typically within the first week after vaccination; the risk is highest in males aged 12-24, at approximately 27 cases per million doses in that group.
Action: Follow the urgency stated and seek prompt or emergency care when indicated. (2)
Contraindications recorded in the clinician database — serious
Symptoms: Contraindications recorded in the clinician database: Contraindications include a history of severe allergic reaction (anaphylaxis) to a previous dose or any component of the vaccine. Precautions include a history of myocarditis or pericarditis after a previous mRNA COVID-19 vaccine, immunocompromised states, and acute moderate or severe illness. Vaccination should be deferred in individuals with acute febrile illness.
Action: Follow the urgency stated and seek prompt or emergency care when indicated. (2)
Interactions
| Medicine or test | Effect | Action |
|---|---|---|
| Recorded interactions | Comirnaty may be given at the same time as other vaccines, but spacing may be recommended for certain live vaccines. Immunosuppressive therapies may reduce the effectiveness of the vaccine. No significant drug-drug interactions have been identified. |
Pregnancy, breastfeeding, kidney/liver function, age
Pregnancy
The FDA prescribing information reports no data on major birth defects or miscarriage risk with Comirnaty use before 24 weeks gestation. In a placebo-controlled trial where pregnant women received Comirnaty from 24-34 weeks gestation, a numerical imbalance in pre-eclampsia was seen in vaccine recipients (3.7%) versus placebo (1.2%), but the data were insufficient to establish or rule out a causal link, and congenital-anomaly rates were also not conclusively different between groups. Animal studies in rats showed no vaccine-related harm to fertility or fetal/postnatal development. Pregnant individuals with COVID-19 are at increased risk of severe disease. Discuss the benefits and risks with a healthcare provider. (2)
Breastfeeding
The FDA prescribing information states it is not known whether Comirnaty is excreted in human milk, and data are not available on its effects on the breastfed infant or on milk production. The developmental and health benefits of breastfeeding should be weighed against the mother's clinical need for the vaccine and any potential effects on the breastfed child, in discussion with a healthcare provider. (2)
Children
The current FDA-approved Comirnaty formula is authorized as a single dose for children 5 through 11 years old (10 mcg, 0.3 mL) who have at least one underlying condition placing them at higher risk of severe COVID-19 — not for children generally, and not for children under 5 under the current approval. This replaces the DB's original multi-dose, broader-age-range schedule, which reflected an earlier formulation's authorization. (2)
Renal_impairment
Comirnaty is an intramuscular vaccine, not a systemically cleared drug requiring dose titration; the FDA prescribing information does not include renal- or hepatic-impairment dosing subsections, and no dose adjustment based on kidney or liver function is described for any age group. People with significant kidney or liver disease should discuss vaccination timing and monitoring with their healthcare provider, as with any vaccine in an immunocompromised or chronically ill patient. (2)
Hepatic_impairment
Comirnaty is an intramuscular vaccine, not a systemically cleared drug requiring dose titration; the FDA prescribing information does not include renal- or hepatic-impairment dosing subsections, and no dose adjustment based on kidney or liver function is described for any age group. People with significant kidney or liver disease should discuss vaccination timing and monitoring with their healthcare provider, as with any vaccine in an immunocompromised or chronically ill patient. (2)
Monitoring
(2)Storage
Store frozen vials at -90°C to -60°C (-130°F to -76°F) until ready for use. Once thawed, vials may be stored refrigerated at 2°C to 8°C (36°F to 46°F) for up to 10 weeks. Do not refreeze once thawed. Follow local healthcare-facility storage guidelines; this is a provider-administered vaccine and is not stored by patients at home.
Professional information
Clinician-facing context only. This section does not replace current product labeling.
General
Indication: COVID-19 prevention
Dose summary: Current FDA-approved formula: a single 0.3 mL dose (30 mcg prefilled syringe for 12 years and older/65+; 10 mcg single-dose vial for 5-11 years), restricted to people 65+ or people 5-64 with a qualifying underlying condition. If previously vaccinated with any COVID-19 vaccine, give at least 2 months after the last dose. (The DB's original 2-dose, 21-day-interval schedule reflected an earlier vaccine formulation's authorization and is superseded by this current single-dose schedule.)
Renal context: The FDA prescribing information does not include a renal-impairment dosing subsection for Comirnaty; as an intramuscular vaccine, no dose adjustment based on kidney function is described. (2)
Hepatic guidance
The FDA prescribing information does not include a hepatic-impairment dosing subsection for Comirnaty; as an intramuscular vaccine, no dose adjustment based on liver function is described.
Frequently asked questions
How effective is Comirnaty against COVID-19?
Comirnaty has been shown to be highly effective at preventing symptomatic COVID-19 and severe outcomes, especially after the full primary series and recommended boosters. Effectiveness may decrease over time, but booster doses help restore protection.
Can I get COVID-19 from the Comirnaty vaccine?
No, Comirnaty does not contain live virus and cannot cause COVID-19. It uses mRNA to instruct your body to build immunity.
What should I do if I have a severe allergic reaction after the vaccine?
Seek emergency medical care immediately. Symptoms may include difficulty breathing, swelling of the face or throat, rapid heartbeat, or a severe rash.
Is Comirnaty safe for pregnant or breastfeeding women?
Pregnancy is a condition that can increase the risk of severe COVID-19, which may make a pregnant person eligible under the current formula's risk-factor-based authorization; the FDA source reviewed for this content did not provide specific pregnancy/lactation safety or efficacy data beyond referencing the relevant label sections. Discuss your individual eligibility and the current evidence with your healthcare provider.
How long does protection from Comirnaty last?
Protection is highest in the first few months after vaccination and decreases over time. Booster doses are recommended to maintain strong protection.
Can children receive Comirnaty?
Under the current FDA-approved formula, Comirnaty is authorized for children 5 through 11 years old only if they have an underlying condition that puts them at higher risk of severe COVID-19; it is not currently authorized for children under 5. This is narrower than earlier formulations, which were authorized for children as young as 6 months. Ask your child's healthcare provider whether your child currently qualifies.
What should I do if I miss my scheduled dose?
The current FDA-approved formula is a single dose (not a multi-dose series), so there is no 'second dose' to miss. If you have not yet received your eligible dose, or need a subsequent season's dose after the required interval from your last COVID-19 vaccine, contact your healthcare provider to schedule it as soon as possible.
What happens if I take too much Comirnaty (COVID‑19 vaccine)?
Comirnaty is administered by a healthcare professional in a controlled setting, making overdose highly unlikely. The vaccine is given in specific doses. If you believe you have received an incorrect dose or experience any unusual or severe reactions after vaccination, you should immediately inform the healthcare provider and seek emergency medical help if necessary.
Can I drink alcohol while taking Comirnaty (COVID‑19 vaccine)?
There are no specific contraindications against consuming alcohol after receiving the Comirnaty vaccine. However, it is generally advisable to avoid excessive alcohol intake around the time of vaccination, as it can potentially suppress the immune system or mask mild vaccine side effects. Consult your healthcare provider for personalized advice.
Is Comirnaty (COVID‑19 vaccine) safe during pregnancy?
The current FDA-approved formula's eligibility is based on age (65+) or an underlying condition that increases risk of severe COVID-19 (ages 5-64), which pregnancy may qualify under; the source reviewed for this content did not provide detailed pregnancy-specific safety/efficacy data. Discuss your eligibility and the current evidence with your healthcare provider to make an informed decision.
What is the mechanism of action of COVID-19 mRNA vaccine (nucleoside-modified)?
Comirnaty is an mRNA vaccine that encodes the full-length spike (S) protein of SARS-CoV-2. After intramuscular injection, the mRNA is taken up by host cells, which then transiently express the spike protein. This triggers both humoral (antibody-mediated) and cellular (T-cell mediated) immune responses, leading to the development of immunity against COVID-19. (2)
What is the generic name of COVID 19 MRNA Vaccine (Nucleoside Modified)?
The generic name is COVID-19 mRNA vaccine (nucleoside-modified). It is sold under brand names including BNT162b2, Comirnaty, Pfizer-BioNTech COVID-19 Vaccine.
What class of drug is COVID-19 mRNA vaccine (nucleoside-modified)?
COVID 19 MRNA Vaccine (Nucleoside Modified) is classed as: Vaccine (mRNA-based).
References
- Comirnaty (COVID-19 vaccine) - clinician-authored medicine recordMedGuideGlobal · United States · accessed 2026-08-06 · source 1
- COMIRNATY (COVID-19 Vaccine, mRNA) 2025-2026 Formula prescribing informationU.S. Food and Drug Administration (DailyMed) / Pfizer · United States · accessed 2026-08-06 · source 2
Brand names by country
Single-ingredient COVID-19 mRNA vaccine (nucleoside-modified) names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.