Top 5 Takeaways:

  1. One-Dose JYNNEOS Vaccine Efficacy: One dose of JYNNEOS vaccine, administered ≥14 days before illness onset, demonstrated some protective effects against mpox, including reduced symptoms and lower hospitalization rates compared to unvaccinated individuals.
  2. Reduced Symptom Severity in Vaccinated Individuals: Vaccinated individuals showed significantly lower odds of experiencing fever, headache, malaise, myalgia, and chills compared to their unvaccinated counterparts.
  3. Hospitalization Rates: Only 2% of vaccinated persons were hospitalized due to mpox, in contrast to 8% of unvaccinated individuals.
  4. Demographic Disparities: A higher proportion of vaccinated mpox patients were White compared to unvaccinated patients, highlighting potential racial and ethnic disparities in vaccine access and acceptance.
  5. Encouragement for Full Vaccination: The findings underscore the importance of completing the 2-dose JYNNEOS vaccination series and continuing nonvaccine-related prevention strategies for optimal protection.

Original Article Author and Citation

Corresponding Author

Jennifer L. Farrar,

Suggested Citation

Farrar JL, Lewis NM, Houck K, et al. Demographic and Clinical Characteristics of Mpox in Persons Who Had Previously Received 1 Dose of JYNNEOS Vaccine and in Unvaccinated Persons — 29 U.S. Jurisdictions, May 22–September 3, 2022. MMWR Morb Mortal Wkly Rep 2022;71:1610–1615. DOI:


The report analyzes the impact of a single dose of JYNNEOS vaccine on mpox infection, comparing the clinical and demographic characteristics of vaccinated and unvaccinated individuals. The study included data from 29 U.S. jurisdictions, focusing on cases reported between May 22 and September 3, 2022.


The study utilized a standardized data collection form, including demographic characteristics, vaccination history, medical history, and potential exposures. Cases were categorized as vaccinated (received 1 dose of JYNNEOS vaccine ≥14 days before illness onset) and unvaccinated. Statistical analyses were conducted to compare clinical characteristics and outcomes between these groups.


Vaccinated individuals exhibited similar signs and symptoms as unvaccinated patients but reported them less frequently and experienced less severe outcomes. The study also highlighted disparities in vaccine distribution and acceptance among different racial and ethnic groups.


The study concludes that while a single dose of JYNNEOS vaccine provides some protection against mpox, it does not guarantee immunity. The reduced severity of symptoms and lower hospitalization rates among vaccinated individuals underscore the vaccine’s potential benefits. However, it emphasizes the need for completing the 2-dose series and ongoing prevention strategies for optimal protection.

This analysis strengthens our understanding of the JYNNEOS vaccine’s effectiveness and the importance of comprehensive vaccination strategies, particularly in the context of emerging infectious diseases.


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