Smallpox And Mpox Vaccine Side Effects

Medically reviewed by Drugs.com. Last updated on May 22, 2024.

Applies to smallpox and mpox vaccine: suspension.

Precautions

It is very important that you receive the second dose of the vaccine series at the right times and that your doctor check your progress at regular visits to make sure that this medicine is working properly and to check for unwanted effects.

This vaccine may cause a serious allergic reaction, including anaphylaxis, which can be life-threatening and requires immediate medical attention. Call your doctor right away if you have a rash, itching, hoarseness, trouble breathing, trouble swallowing, or any swelling of your hands, face, or mouth after you receive the vaccine.

Fainting may occur after you receive this vaccine. Your doctor may want to observe you after you get the injection to prevent or manage fainting.

You should not receive this vaccine if you are using medicines that weaken your immune system, including steroids, radiation, or cancer medicines.

This vaccine may not protect everyone who receives it.

Serious side effects

Along with its needed effects, smallpox and mpox vaccine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur while taking smallpox and mpox vaccine:

Other side effects

Some side effects of smallpox and mpox vaccine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

For healthcare professionals

Applies to smallpox and mpox vaccine: injectable suspension, subcutaneous suspension.

General adverse events

There were similar proportion of subjects reporting local or systemic reactions of any severity after the second dose, compared to the first dose, except for injection site pain which was more common following dose 1 (79% vs 69%).^[Ref]

Cardiovascular

• Common (1% to 10%): Subcutaneous: Cardiac Adverse Events of Special Interest (AESIs - any cardiac signs or symptoms, changes in ECG, or troponin-1 elevations above 2 times the upper limit of normal)^[Ref]

None of the reported cardiac AESIs causally related to vaccination were considered serious.^[Ref]

Gastrointestinal

• Very common (10% or more): Subcutaneous: Nausea (17%); Intradermal: Nausea (23%), change in appetite (20%)^[Ref]

Local

• Very common (10% or more): Subcutaneous: Pain (85%), redness (60%), swelling (51%), induration (45%), itching (43%); Intradermal: Erythema (99.5%), induration (99.5%), itchiness (89%), pain at injection site (65%), underarm pain (20%), underarm swelling (10%)^[Ref]

Musculoskeletal

• Very common (10% or more): Subcutaneous: Muscle pain (43%); Intradermal: Muscle aches (30%), joint pain (18%)^[Ref]

Nervous system

• Very common (10% or more): Subcutaneous: Headache (35%); Intradermal: Headache (41%)^[Ref]

Other

• Very common (10% or more): Subcutaneous: Fatigue (30%), chills (10%); Intradermal: Tiredness (51%), chills (14%)
• Common (1% to 10%): Subcutaneous: Fever^[Ref]

See also:

Further information

Smallpox and mpox vaccine side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer