Mpox vaccination

What you need to know about mpox (formerly called monkeypox) vaccine in Massachusetts.

Table of Contents

About the JYNNEOS vaccine

When properly administered before or soon after exposure, vaccines can help protect against mpox illness.

The vaccine most commonly used for preventing mpox infection is JYNNEOS (also known as Imvamune or Imvanex) which has been licensed by the U.S. Food and Drug Administration (FDA).

In the United States, there is now ample supply of JYNNEOS, being solely distributed by the Centers for Disease Control and Prevention (CDC). Massachusetts has received several allocations of JYNNEOS from the CDC since the beginning of the outbreak in 2022, and has made those doses available to provider sites across the State.

On August 9, 2022, CDC and FDA released an EUA (Emergency Use Authorization) allowing an alternative dose vaccination regimen in people 18 years and over and allowing the use of the JYNNEOS vaccine in individuals younger than 18 years.

The original JYNNEOS approval included the use of two 0.5 mL doses administered subcutaneously (under the skin). The alternative regimen allows the use of two lower doses, 0.1 mL of vaccine administered intradermally (into the skin). Providers administering JYNNEOS vaccine should begin utilizing this alternative dose vaccination regimen as of August 18, 2022.

People who get vaccinated should continue to protect themselves from infection by avoiding close, skin-to-skin contact, including intimate contact, with someone who has mpox.

Data on JYNNEOS can be found on the CDC website.

The CDC has also made available the live replicating smallpox vaccine ACAM2000. However, this vaccine has a number of characteristics that may make it unsuitable for use in the current context, including considerably greater risk to the recipient compared with JYNNEOS. Data on ACAM2000 can be found on the CDC website.


As of October 3, 2022, vaccination will be available to individuals who live or work in Massachusetts and meet the CDC’s current eligibility criteria, which have recently expanded to include individuals at potential risk for mpox in addition to those with possible recent exposure to an individual with mpox:

Persons eligible for post-exposure vaccination (PEP) includes: 

  • Known contacts identified by public health via case investigation, contact tracing, and risk exposure assessments (this may include sexual partners, household contacts, and healthcare workers); as well as
  • Presumed contacts who meet the following criteria:
    • Know that a sexual partner in the past 14 days was diagnosed with mpox
    • Had multiple sexual partners in the past 14 days in a jurisdiction with known mpox

In addition, CDC now allows for pre-exposure vaccination (PrEP) of persons at risk for mpox which includes: 

  • Gay, bisexual, and other men who have sex with men, transgender, gender non-conforming, or nonbinary people who  
    • Have had a diagnosis of or have sought testing for one or more sexually transmitted diseases (i.e., chancroid, chlamydia, gonorrhea, or syphilis) in the past year 
    • Are living with HIV infection 
    • Are on or are eligible to be on HIV PrEP 
    • Have recently had more than one sex partner 
  • People who:
    • Have had sex at a private or commercial sex venue (e.g., sex party, bathhouse) 
    • Have had sex in association with a large public event (e.g., rave, circuit party) in a geographic area where mpox transmission is occurring 
  • Sexual partners of people with the above risks 
  • People who anticipate experiencing the above risks 

When you request vaccine, you will not be asked which of these criteria applies to you. It is sufficient to say that you consider yourself to be at risk for mpox. 

While many of the identified cases are within networks of self-identified gay and bisexual men, other men who have sex with men, and transgender individuals who have sex with men, people of any sexual orientation or gender identity can become infected and spread mpox. 

How to obtain vaccine

JYNNEOS vaccine is available to individuals who live or work in Massachusetts and meet the CDC’s eligibility criteria. See above for eligibility details.

Administration of JYNNEOS is available at any one of the designated health care locations listed below. Healthcare providers are responsible to perform exposure assessment to confirm eligibility prior to scheduling an appointment for a vaccine. Vaccination sites designated below may also offer vaccination on a walk-in basis (no appointment required).

Please contact sites first to confirm that walk-in vaccinations are offered.

Vaccine appointments are available from these clinics:

Information for health care providers

Visit information for health care providers for details on smallpox/mpox vaccine (JYNNEOS™) administration, eligibility, and availability in Massachusetts. 

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