Mpox in the United States
The US had the second-highest mpox case count globally in 2022 and now monitors for Clade Ib importations while maintaining a vaccination program for at-risk communities.
The 2022 US Mpox Outbreak
| Metric | Data |
| Peak cases | >30,000 cases (2022) |
| Hardest-hit cities | New York City, Los Angeles, San Francisco, Chicago |
| JYNNEOS doses administered | >1.2 million (US, 2022–2023) |
| National Emergency declared | August 4, 2022 (ended Feb 2023) |
The US 2022 outbreak was part of the global Clade IIb wave that spread through sexual contact networks, predominantly affecting gay, bisexual, and other men who have sex with men. Early response was hampered by vaccine supply shortfalls — JYNNEOS doses were initially scarce, and the US pivot to intradermal dosing (1/5th the subcutaneous dose) in August 2022 helped stretch limited supply.
JYNNEOS Vaccination Program
JYNNEOS (Bavarian Nordic) is the primary mpox vaccine in the US. It is FDA-approved, two-dose, non-replicating (safe for immunocompromised). Intradermal administration (preferred in the 2022 outbreak) uses smaller doses with equivalent immunogenicity. As of 2025, the US Strategic National Stockpile holds sufficient JYNNEOS to respond to future outbreaks. Vaccination recommendations focus on highest-risk individuals.
Clade Ib Importation Risk (2024–2025)
WHO declared a new PHEIC for Clade Ib mpox in August 2024. The US has detected sporadic imported Clade Ib cases in travelers returning from affected African countries. Current risk of domestic spread is considered low — JYNNEOS vaccine provides cross-protection against Clade I. CDC advises travelers to affected regions to avoid close skin contact with infected people and practice strict mosquito (actually: contact) precautions.
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Frequently Asked Questions
CDC recommends JYNNEOS for people with known mpox exposure, gay/bisexual/MSM with multiple partners, transgender people, sex workers, and people with HIV. Contact a local sexual health clinic, health department, or call 1-800-CDC-INFO for vaccine access.
Sporadic imported Clade Ib cases have been detected in 2024–2025. Sustained community transmission has not been established. JYNNEOS vaccine provides cross-protection against Clade I. The risk to the general US public is low.
Sources: CDC mpox case tracker; HHS JYNNEOS rollout data; WHO mpox PHEIC declarations; NEJM 2022 mpox characterization.
Related: Mpox overview · Mpox guide 2025