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Smallpox/Mpox Vaccine


Smallpox/Mpox vaccine is approved by the FDA as a primary (2-dose) series to prevent infection caused by smallpox or mpox vaccine in people 18 years of age and older. The FDA has also approved an Emergency Use Authorization (EUA) for the Smallpox/Mpox vaccine (Jynneos) to allow:

  • 2 doses of smallpox/Mpox vaccine given 4 weeks apart in children and adolescents younger than 18 years of age.

Why get vaccinated?

Smallpox/Mpox vaccine can prevent infection with some types of orthopoxviruses including Smallpox, Mpox, and Vaccinia viruses.

Smallpox infection can cause a serious illness characterized by rash and fever that may result in death, for some.

Mpox infection can cause an illness similar to Smallpox. Although generally milder, it can still cause death.

Vaccinia virus infection can occur after someone is exposed to a person or an animal who has been exposed to the virus. It generally causes a self-limiting illness.

What is Smallpox/Mpox vaccine?

Smallpox/Mpox vaccine is approved to prevent Smallpox or Mpox disease in adults at high risk for Smallpox or mpox infection. The Center for Diseases Control and Prevention recommend:

  • giving the vaccine to certain laboratory workers and emergency response team members who may be exposed to any of the covered orthopox viruses
  • consider giving the vaccine to people who administer ACAM2000 (Smallpox vaccine) or who care for people that are infected with an orthopox virus

Smallpox/Mpox vaccine is given as 2 doses 4 weeks apart. If you have already received another Smallpox vaccine, you may only need 1 dose.

Booster doses are recommended every 2 to 10 years to people who remain at high risk of exposure to orthopox viruses.

Smallpox/Mpox vaccine can be administered at the same time as other vaccines.

Talk with your healthcare provider

Tell your vaccination provider if the person getting the vaccine:

  • Has had an allergic reaction after a previous dose of Smallpox vaccine, or has any severe life-threatening allergies.
  • Is pregnant or thinks they might be pregnant or is breastfeeding.
  • Has a weakened immune system.

In some cases, your healthcare provider may decide to postpone pre-exposure Smallpox/Mpox vaccination until a future visit.

People with minor illnesses, such as a cold, may be vaccinated. People who are moderately or severely ill should usually wait until they recover before getting pre-exposure Smallpox/Mpox vaccine.

If you have been recommended to receive Smallpox/Mpox vaccine due to an exposure to Mpox vaccine, you should receive it regardless of concurrent illness, pregnancy, breastfeeding or weakened immune system.

Your healthcare provider can give you more information.

What are the risks of a vaccine reaction?

  • Soreness, redness, itching or swelling where the shot is given can happen after Smallpox/Mpox vaccination.
  • Fatigue, headache and muscle pain can also happen after Smallpox/Mpox vaccination.

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

As with any medication, there is a very remote chance of a vaccine causing a severe allergic reaction, other serious injury, or death.

What if there is a serious problem?

An allergic reaction could occur after the vaccinated person leaves the clinic. If you see signs of a severe allergic reaction (hives, swelling of the face and throat, difficulty breathing, a fast heartbeat, dizziness, or weakness), call 9-1-1 and get the person to the nearest hospital.

For other signs that concern you, call your health care provider.

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 the VAERS website at or call 1-800-822-7967. VAERS is only for reporting reactions, and VAERS staff members do not give medical advice.

The National Vaccine Injury Compensation Program

The National Vaccine Injury Compensation Program (VICP) is a federal program that was created to compensate people who may have been injured by certain vaccines. Claims regarding alleged injury or death due to vaccination have a time limit for filing, which may be as short as two years. Visit the VICP website at or call 1-800-338-2382 to learn about the program and about filing a claim.

How can I learn more?

Brand names

  • Jynneos®
Last Revised - 04/15/2023