Geneva, Switzerland — 5 December 2025 — The World Health Organization published a Disease Outbreak News report revealing that community transmission of clade Ib monkeypox virus (MPXV) is now occurring across multiple WHO regions, despite the lifting of the second public health emergency of international concern (PHEIC) on 5 September 2025. Between 5 September and 24 November 2025, 43 new confirmed clade Ib cases were reported across six WHO regions, with 24 cases having no recent international travel history — indicating local transmission.
Based on these findings, WHO now considers Italy, Malaysia, the Netherlands, Portugal, Spain, and the United States of America to be experiencing community transmission of clade Ib MPXV.
The Global Picture
The 43 cases span every WHO region except the Eastern Mediterranean and South-East Asia regions (where all reported cases were travel-related). The distribution reveals a virus that is quietly establishing itself in new populations:
| WHO Region | Countries with Cases | Community Transmission Established |
|---|---|---|
| African Region | Namibia (first cases), plus ongoing transmission in 11 countries | Burundi, DRC, Kenya, Malawi, Mozambique, Republic of Congo, Rwanda, South Africa, Tanzania, Uganda, Zambia |
| Americas | Canada, United States | United States (southern California) |
| European Region | Belgium, France, Germany, Greece, Ireland, Italy, Netherlands, Portugal, Spain, UK | Italy, Netherlands, Portugal, Spain |
| Western Pacific | Australia, Japan, Malaysia | Malaysia |
Key Country Highlights
The Netherlands
The Netherlands reported nine cases of clade Ib MPXV, all without relevant travel history — the first such cases in the country. Eight cases were among individuals who identify as MSM, and six of those reported visiting the same sex-on-premises venue. Prior to 5 September, the Netherlands had not reported any clade Ib cases.
Spain
Spain reported six cases in individuals with no recent international travel or known contact with mpox cases, all among MSM. These were the first clade Ib cases reported in the country.
United States
Three unrelated cases were detected in Long Beach and Los Angeles counties, California. All occurred among MSM, none had recent international travel, and one was immunocompromised. All three were hospitalised but fully recovered. Viral genomic sequencing indicated the cases may be linked to a previously reported case from August 2025.
Namibia
Namibia reported its first-ever mpox cases: one probable case linked to travel within the African Region and two confirmed household contacts. No further cases followed detection of the cluster.
Why Community Transmission Is Emerging Now
WHO's risk assessment offers several explanations for why clade Ib is now establishing itself in new countries:
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Asymptomatic and paucisymptomatic infections: Some infections produce few or no symptoms, leading to undetected onward transmission, particularly through sexual contact.
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Waning immunity: Since the peak of mpox vaccination activities in late 2022, new cohorts of sexually active individuals have entered the population without prior infection or vaccination. Data on vaccine effectiveness, duration of protection, and cross-clade immunity remain limited.
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Sexual transmission as the primary amplifier: Sexual contact remains the primary mode of transmission in most settings, and clade Ib has demonstrated the ability to spread through both heterosexual and MSM sexual networks.
WHO Risk Assessment
WHO assesses the public health risk posed by clade Ib MPXV as moderate for men who have sex with men with new and/or multiple partners, and low for the general population in most countries. The moderate risk for MSM is justified by higher exposure risk and the prevalence of advanced HIV infection in this group in many contexts, which increases the risk of severe mpox disease and death.
People living with untreated or uncontrolled HIV remain at the highest risk of severe mpox outcomes. WHO strongly recommends early HIV testing for all patients with suspected or confirmed mpox and rapid initiation of antiretroviral therapy (ART) for those living with untreated HIV.
Vaccination and Response
WHO recommends three vaccines for mpox: MVA-BN (non-replicating, prequalified by WHO), LC16m8 (minimally replicating, WHO emergency use listed), and ACAM2000 (replicating, for use when others are unavailable). In the context of ongoing outbreaks, vaccination is recommended for individuals at high risk of exposure.
WHO also recommends a temporary outbreak response measure of administering MVA-BN vaccine via intradermal injection at one-fifth of the standard subcutaneous dose — known as fractional dosing — which has been shown to be effective and safe, enabling vaccination of four to five times as many people.
In the WHO African Region, 16 countries have received mpox vaccines and are vaccinating people at risk. A continental mpox response is ongoing, including all main response pillars coordinated by Africa CDC.
The African Context
While the global focus has shifted to newly affected countries, the African Region continues to bear the heaviest burden. Community transmission persists in 11 African countries: Burundi, the Democratic Republic of the Congo, Kenya, Malawi, Mozambique, Republic of Congo, Rwanda, South Africa, Tanzania, Uganda, and Zambia.
In many African settings, transmission has been driven by heterosexual contact among people with multiple casual sexual partners in linked sexual networks, followed by secondary spread within households. Children, pregnant women, and immunocompromised individuals remain at elevated risk of severe disease and death.
Sources
- World Health Organization, Disease Outbreak News: Broader transmission of mpox due to clade Ib MPXV – Global situation (5 December 2025). Available at:
- WHO Strategic framework for enhancing prevention and control of mpox (2024–2027). Available at:
- Africa CDC Mpox Continental Response Plan 2.0. Available at:
- BMJ Global Health: Mpox response in the Democratic Republic of the Congo (2025). Available at:
FIRAT Editorial Board
Institutional Research Desk · Foresight Institute of Research and Translation
The collective editorial and research translation board of FIRAT, synthesising peer-reviewed evidence, policy briefs, and division milestones across our seven foundational research pillars.
