CDC is updating webpages with the term "mpox" to reduce stigma and other issues associated with prior terminology. This change is aligned with the recent World Health Organization decision.

Mpox Vaccination Basics

Mpox (formerly known as monkeypox) is caused by a virus that is related to the virus that causes smallpox. JYNNEOS is a 2-dose vaccine developed to protect against mpox and smallpox infections. People need to get both doses of the vaccine for the best protection against mpox. The second dose should be given 4 weeks after the first dose.

Vaccination is an important tool in stopping the spread of mpox. People who are vaccinated should continue to avoid close, skin-to-skin contact with someone who has mpox.

CDC recommends vaccination against mpox if:

  • You had known or suspected exposure to someone with mpox.
  • You had a sex partner in the past 2 weeks who was diagnosed with mpox.
  • You are a gay, bisexual, or other man who has sex with men, or are a transgender, nonbinary, or gender-diverse person who has had any of the following within the past 2 weeks:
    • More than one sex partner.
    • Sex at a commercial sex venue (like a sex club or bathhouse).
    • Sex at an event, venue, or in an area (city or county for example) where mpox transmission is occurring.
  • You are a gay, bisexual, or other man who has sex with men or a transgender, nonbinary, or gender-diverse person who in the past 6 months has had any of the following:
    • A new diagnosis of one or more sexually transmitted diseases (e.g., HIV, chancroid, chlamydia, gonorrhea, or syphilis).
    • More than one sex partner.
  • In the past 6 months:
    • You had sex at a commercial sex venue (like a sex club or bathhouse).
    • You had sex at an event, venue, or in an area (city or county for example) where mpox transmission is occurring.
  • You have a sex partner who identifies with any of the above scenarios.
  • You anticipate experiencing any of the above scenarios.
  • You work with orthopoxviruses in a laboratory or are part of an orthopoxvirus and health care worker response team.

You should NOT get the vaccine if:

You had a severe allergic reaction (such as anaphylaxis) after getting your first dose of the JYNNEOS vaccine.

You should take extra caution if:

You had an allergic reaction to any vaccine. You may still be vaccinated with JYNNEOS, but your provider may need to observe you for 30 minutes after you get vaccinated to make sure you don’t develop an allergic reaction.

Talk to your healthcare provider if you had an allergic reaction to the antibiotics gentamicin or ciprofloxacin, or chicken or egg protein.

How the vaccine is given

  • The vaccine will be given between the top layers of your skin; this is called an intradermal vaccination. It can be placed in your forearm or other areas, including your upper back just below the shoulder blade or the skin of your shoulder above the deltoid muscle.
  • If preferred, you can also ask for the vaccine to be given to you “subcutaneously.” This means that the vaccine will be injected in the fat layer underneath the skin on the back of your upper arm (triceps).
  • If you have ever had keloid scars (thick, raised scars) or are under 18, ask for the vaccine to be given to you subcutaneously.
  • Getting the vaccine intradermally or subcutaneously appears to be equally effective against mpox.

Although early findings suggest that the first dose of JYNNEOS vaccine gives some protection against mpox, two doses are recommended to provide stronger prevention. Whether you get the vaccine subcutaneously or intradermally, you should still get two doses. The second dose should be given 4 weeks (28 days) after the first dose. If you can’t get your second dose on time, you should get it as soon as possible to complete the series.

If you don’t want the vaccine given in the skin of your forearm, ask to get it in the skin of your upper back or the skin of your shoulder instead. You can also ask to be given the vaccine subcutaneously in the fat layer underneath the skin on the back of your upper arm.

How intradermal vaccination works

There are many immune cells in the skin tissue just underneath the top layer of your skin. When a vaccine is given between the layers of skin, you can generate a strong immune response using a smaller amount of vaccine.

The smaller amount of JYNNEOS vaccine given between the top layers of skin produces a similar immune response as the standard dose given in the fat layer underneath the skin (subcutaneous).

JYNNEOS vaccine is effective at reducing the risk of mpox disease, with two doses providing the best protection, regardless if the vaccine is given intradermally or subcutaneously.

Side effects

Not everyone has side effects, but some people do. The most common side effects after JYNNEOS vaccination are pain, redness, and itching at the spot where the vaccine is given. You might also experience fever, headache, tiredness, nausea, chills, and muscle aches. These are signs that your immune system is responding, not that you’re getting sick.

When JYNNEOS vaccine is given intradermally, some people have reported less pain after vaccination but more side effects like itching, swelling, redness, thickening of the skin, and skin discoloration at the spot where the vaccine was given. Some of these side effects may last for several weeks. If you have concerns about receiving the vaccine intradermally, you can ask for the vaccine to be given to you subcutaneously in the fat layer underneath the skin on the back of your upper arm (triceps).

V-safe after vaccination health checker

Additional information is still being gathered on side effects people might experience after vaccination, and the v-safe after vaccination health checker is a way to provide information about how you feel after your vaccination.

How long it takes for the vaccine to work

You can start to have an immune response after the first dose of JYNNEOS, but it takes two weeks after the second dose to be the most protected.

It’s not known how long protection might last, or if protection might decrease over time. CDC is analyzing the current data and conducting studies to enhance the knowledge on how well the JYNNEOS vaccine works during the current mpox outbreak, as well as how long protection might last. These studies will be used to make future vaccine recommendations.

Where you can get vaccinated

In some large cities, mpox vaccines may be available at the health department, public health clinics, hospitals, or even at large social gatherings or venues.

  • In other areas, mpox vaccines may only be available from the health department.
  • Contact your local health department to see what the vaccination options are in your community.
  • Building Healthy Online Communities (BHOC) has an mpox vaccine locator tool. This tool is not affiliated with CDC but can help you find locations that provide the mpox vaccines near you.
Find Mpox Vaccines

Enter your ZIP code in the locator to find locations providing mpox vaccines.

Vaccine cost

  • Mpox vaccines are free. Providers must give you the vaccine regardless of your ability to pay the administration fee.
  • The providers may bill a program or plan that covers the mpox vaccine administration fee (like your private insurance or Medicare/Medicaid).