Top 5 Takeaways

  1. New Vaccine Option: JYNNEOS, a replication-deficient Vaccinia virus vaccine licensed in 2019, is now recommended by ACIP for preexposure prophylaxis against orthopoxviruses, offering an alternative to ACAM2000.
  2. Reduced Risk Profile: JYNNEOS, being replication-deficient, poses lower risks of adverse events compared to the replication-competent ACAM2000, making it a safer choice for certain populations.
  3. Recommendation for Boosters: ACIP advises booster doses of JYNNEOS every 2 years for those exposed to more virulent orthopoxviruses and every 10 years for those exposed to less virulent viruses.
  4. Specific Populations: The vaccine is recommended for lab personnel, healthcare workers handling orthopoxviruses, and response team members, with tailored guidelines for booster intervals.
  5. Clinical Considerations: Decisions between JYNNEOS and ACAM2000 should consider the individual’s risk factors and occupational exposure, with JYNNEOS offering a significant reduction in serious adverse events and no requirement for a ‘take’ to confirm vaccination efficacy.

Original Article Author and Citation

  • Corresponding Author: Agam K. Rao –
  • Suggested Citation: Rao AK, Petersen BW, Whitehill F, et al. “Use of JYNNEOS (Smallpox and Monkeypox Vaccine, Live, Nonreplicating) for Preexposure Vaccination of Persons at Risk for Occupational Exposure to Orthopoxviruses: Recommendations of the Advisory Committee on Immunization Practices — United States, 2022.” MMWR Morb Mortal Wkly Rep 2022;71:734–742. DOI:


JYNNEOS is now an approved alternative to ACAM2000 for those at occupational risk of exposure to orthopoxviruses, providing a safer option with fewer adverse effects and no requirement for lesion formation post-vaccination.


The ACIP’s Orthopoxvirus Work Group conducted systematic reviews and employed the GRADE approach to evaluate the vaccine from 2020 to 2021, concluding with recommendations based on evidence for primary and booster vaccinations.


The introduction of JYNNEOS enriches the orthopoxvirus prevention toolkit, especially significant in the context of increasing occupational exposures and the need for safer vaccination options.


The adoption of JYNNEOS reflects a strategic advancement in public health policy aimed at enhancing safety and effectiveness of orthopoxvirus prophylaxis, particularly in sensitive or at-risk populations.

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