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URL of this page: https://medlineplus.gov/druginfo/meds/a622052.html

Smallpox and Mpox Vaccine, Live

Why get vaccinated?

Smallpox and mpox vaccine, live may prevent smallpox and mpox that may occur with infection due to orthopoxviruses.

Infection with orthopoxviruses can cause the following: life-threatening skin rashes and lesions, muscle aches, fever, swollen lymph nodes.

Smallpox and mpox vaccine, live contains a live virus that has been weakened so it does not cause disease but can still stimulate the body to make antibodies against the virus to provide a defense against potential infection.

How is the vaccine given?

Smallpox and mpox vaccine comes as a suspension (liquid) to be given subcutaneously (under the skin) by a healthcare provider.

Smallpox and mpox vaccine is given as two doses given 4 weeks apart.

What should you tell the person who is giving the vaccine?

Tell your vaccine provider if you:

  • have had an allergic reaction to this vaccine, any part of this vaccine, any other vaccine or any drug, food or substance. Tell your vaccine provider about the allergy and what symptoms you had.
  • are immunocompromised due to a medical condition or treatment.
  • are pregnant or breastfeeding.

In some cases, your health care provider may decide to postpone vaccination to a future visit.

What are the risks from vaccination?

Side effects that have been reported with smallpox and mpox vaccine include:

  • pain, redness, swelling, itching, or thickening of the skin near the site of injection
  • headache
  • tiredness
  • muscle pain

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately or get emergency medical treatment:

  • rash, hives, difficulty breathing or swallowing

People sometimes faint after medical procedures, including vaccination. Tell your provider if you feel dizzy or have vision changes or ringing in the ears.

Adverse reactions should be reported to the Vaccine Adverse Event Reporting System (VAERS). Your health care provider will usually file this report, or you can do it yourself. Visit https://vaers.hhs.gov or call 1-800-822-7967. VAERS is only for reporting reactions, and VAERS staff members do not give medical advice.

How can I learn more?

Brand names

  • Jynneos®
Last Revised - 07/15/2026