This medication belongs to a group of medications known as vaccines. It is used to prevent coronavirus disease 2019 (COVID-19) caused by the SARS-CoV-2 virus. This vaccine increases a person's defences against coronavirus infection by introducing genetic information, in the form of messenger RNA, for a piece of virus into the body. This causes your body to produce pieces of the virus which then stimulate the production of your own antibodies (cells designed to attack that particular virus). These antibodies remain in the body ready to attack any future SARS-CoV-2 virus that may cause infection. You cannot get COVID-19 from the vaccine.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

This medication is given as an intramuscular (into the upper arm) injection. The dose varies depending on the age of the person being vaccinated.

It is important this vaccine be given exactly as recommended by your health care professional. If you miss an appointment to receive this vaccine, contact your health care professional as soon as possible to reschedule your appointment. All vaccines should be added to your immunization record.

This vaccine requires specific and extreme storage conditions. It will be stored, supplied, and administered by a health care professional.

Comirnaty Original & Omicron BA.4/BA.5 (no dilution)
Each vial of white-to-off-white, sterile, preservative-free, frozen suspension for intramuscular injection, contains tozinameran nucleoside-modified messenger RNA (modRNA) encoding the viral spike glycoprotein (S) of SARS-CoV-2 original strain and famtozinameran modRNA encoding the viral spike glycoprotein (S) of SARS-CoV-2 Omicron variant lineages BA.4 and BA.5. Nonmedicinal ingredients: ALC-0315 = ((4-hydroxybutyl) azanediyl)bis (hexane-6,1-diyl)bis(2-hexyldecanoate), ALC-0159 = 2-[(polyethylene glycol)-2000]-N,N-ditetradecylacetamide, 1,2-distearoyl-sn-glycero-3-phosphocholine, cholesterol, sodium chloride, sucrose, tromethamine, tromethamine hydrochloride, and water for injection.

Comirnaty Original & Omicron BA.4/BA.5 (requires dilution)
Each vial of white-to-off-white, sterile, preservative-free, frozen suspension for intramuscular injection, contains tozinameran nucleoside-modified messenger RNA (modRNA) encoding the viral spike glycoprotein (S) of SARS-CoV-2 original strain and famtozinameran modRNA encoding the viral spike glycoprotein (S) of SARS-CoV-2 Omicron variant lineages BA.4 and BA.5. Nonmedicinal ingredients: ALC-0315 = ((4-hydroxybutyl) azanediyl)bis (hexane-6,1-diyl)bis(2-hexyldecanoate), ALC-0159 = 2-[(polyethylene glycol)-2000]-N,N-ditetradecylacetamide, 1,2-distearoyl-sn-glycero-3-phosphocholine, cholesterol, sodium chloride, sucrose, tromethamine, tromethamine hydrochloride, and water for injection.

Comirnaty XBB.1.5 30 µg/0.3 mL
Each vial of white-to-off-white, sterile, preservative-free, frozen suspension for intramuscular injection, contains raxtozinameran nucleoside-modified messenger RNA (modRNA) encoding the viral spike glycoprotein (S) of SARS-CoV-2 Omicron variant lineage XBB.1.5. Nonmedicinal ingredients: ALC-0315 = ((4-hydroxybutyl) azanediyl)bis (hexane-6,1-diyl)bis(2-hexyldecanoate), ALC-0159 = 2-[(polyethylene glycol)-2000]-N,N-ditetradecylacetamide, 1,2-distearoyl-sn-glycero-3-phosphocholine, cholesterol, sodium chloride, sucrose, tromethamine, tromethamine hydrochloride, and water for injection.

Comirnaty XBB.1.5 10 µg/0.3 mL Each vial of white-to-off-white, sterile, preservative-free, frozen suspension for intramuscular injection, contains raxtozinameran nucleoside-modified messenger RNA (modRNA) encoding the viral spike glycoprotein (S) of SARS-CoV-2 Omicron variant lineage XBB.1.5. Nonmedicinal ingredients: ALC-0315 = ((4-hydroxybutyl) azanediyl)bis (hexane-6,1-diyl)bis(2-hexyldecanoate), ALC-0159 = 2-[(polyethylene glycol)-2000]-N,N-ditetradecylacetamide, 1,2-distearoyl-sn-glycero-3-phosphocholine, cholesterol, sodium chloride, sucrose, tromethamine, tromethamine hydrochloride, and water for injection.

Comirnaty XBB.1.5 3 µg/0.2 mL
Each vial of white-to-off-white, sterile, preservative-free, frozen suspension for intramuscular injection, contains raxtozinameran nucleoside-modified messenger RNA (modRNA) encoding the viral spike glycoprotein (S) of SARS-CoV-2 Omicron variant lineage XBB.1.5. Nonmedicinal ingredients: ALC-0315 = ((4-hydroxybutyl) azanediyl)bis (hexane-6,1-diyl)bis(2-hexyldecanoate), ALC-0159 = 2-[(polyethylene glycol)-2000]-N,N-ditetradecylacetamide, 1,2-distearoyl-sn-glycero-3-phosphocholine, cholesterol, sodium chloride, sucrose, tromethamine, tromethamine hydrochloride, and water for injection.

Do not take this medication if you are allergic to any ingredients of the medication.

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• arm pain
• chills
• decreased appetite (6 months to 2 years)
• diarrhea
• fever
• headache
• irritability (6 months to 2 years)
• joint pain
• muscle pain
• nausea
• numbness or decreased sense of touch
• rash (6 months to 2 years)
• redness, swelling, tenderness, or pain at place of injection
• sweating
• swollen lymph nodes
• tingling, itching, or prickling sensation
• tiredness
• vomiting

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Seek immediate medical attention if any of the following occur:

• facial paralysis (Bell's palsy)
• symptoms of a serious allergic reaction (such as hives, difficulty breathing, itchy rash on the hands or feet, or swelling of the face, tongue, or throat)
• symptoms of inflammation of tissue surrounding the heart (pericarditis; e.g., chest pain, cough, fast or irregular heartbeat, shortness of breath, weakness or fatigue)
• symptoms of inflammation of the heart muscle (myocarditis; e.g., chest pain, swelling of the feet and legs; fast or irregular heartbeat, shortness of breath, joint stiffness)

Be sure to mention any side effect to your doctor, as it may mean that you are allergic to the vaccine. If so, it would not be safe for you to have more doses of the same type of vaccine.

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Allergic reactions: Rarely, this vaccine may cause severe allergic reactions. If you notice the signs of a severe allergic reaction (hives; trouble breathing or swallowing; or swelling of the lips, face, throat, or tongue), get medical attention immediately.

If you have had an allergic reaction with your first dose of the COVID-19 vaccine, discuss this with your health care professional before you receive the second dose.

Bleeding: People with bleeding disorders, or those who are taking anticoagulants (blood thinners), may experience bruising after receiving an intramuscular injection. Tell your doctor about any bleeding problems you may have and discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Fainting: As with other injectable vaccines, this vaccine may cause fainting. If you notice signs such as dizziness, changes in heart rate, shortness of breath, tingling sensations or sweating, get medical attention immediately.

Immune system: As with any vaccine, this vaccine may not be as effective for people with a weakened immune system (such as those who are on chemotherapy, who have had an organ transplant, have autoimmune diseases, or who have HIV).

Myocarditis and pericarditis: Rarely, cases of inflammation of the heart muscle (myocarditis) or inflammation of the lining outside the heart (pericarditis), have occurred in people who have received this vaccine. If you experience symptoms such as chest pain, shortness of breath, or feelings of a fast, fluttering or pounding heartbeat within a few days of vaccination, get medical attention immediately.

Other illness: If you have a high fever or other illness, discuss with your doctor about rescheduling your appointment to receive this vaccine after you have recovered. It is advisable to wait to receive this vaccine if you have an acute, severe illness with fever.

Pregnancy: This vaccine should not be used during pregnancy unless the benefits outweigh the risks. If you discover you may have been pregnant when you received this medication, contact your doctor immediately.

Breast-feeding: It is not known if this vaccine passes into breast milk. If you are breast-feeding and taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of this vaccine have not been determined for children and adolescents under the age of 6 months.

For a full list of interactions, use the Drug Interaction Checker available on the Drugs.com website.

If you are taking other medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.