21JUL

Europe starts a monthly mpox watch

3 min read

09:12UTC

ECDC launched a monthly clade I mpox bulletin after confirming 336 cases across 15 EU and EEA countries, with local transmission now established in Spain, the Netherlands, Italy and Portugal.

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Key takeaway

ECDC's new monthly mpox bulletin institutionalises tracking of local European transmission that was already established.

The European Centre for Disease Prevention and Control (ECDC) launched a monthly mpox surveillance report on 17 June, having confirmed 336 clade I cases across 15 EU and European Economic Area (EEA) countries between April 2025 and March 2026 ¹. mpox is a viral disease caused by the monkeypox virus; clade I is the more severe of its two lineages, and the EEA extends EU single-market rules to Norway, Iceland and Liechtenstein.

Local transmission, meaning chains with no link to travel from Africa, is now established in at least four countries: Spain, the Netherlands, Italy and Portugal, predominantly among men WHO have sex with men. Cases peaked at 89 in January 2026 and averaged around 80 a month in February and March. ECDC rates the risk to men WHO have sex with men as moderate and to the general population as low.

Clade Ib circulating locally in Europe was reported a fortnight ago , and the recombinant clade Ib/IIb virus before that , so the new bulletin formalises timing rather than marking a discovery. The transmission was already documented; what changes now is that ECDC commits to a standing monthly cadence to track it, an institutional rhythm arriving after the pattern it watches was established rather than before. A monthly report formalises monitoring of spread that European laboratories had been logging case by case for the better part of a year.

Deep Analysis

In plain English

Mpox (previously called monkeypox) is a viral disease that spreads primarily through close skin-to-skin contact, including sexual contact. There are two main variants: clade IIb (which caused a global outbreak in 2022, mainly in Europe and North America) and clade I (more severe, originally from central Africa). Clade I has now been confirmed spreading locally inside Europe: people are catching it from each other within EU countries, without any link to Africa travel. ECDC (the EU's disease monitoring agency) has counted 336 confirmed clade I cases across 15 EU and European Economic Area countries between April 2025 and March 2026. In four countries (Spain, the Netherlands, Italy, and Portugal) people contracted it within the country rather than abroad. Most cases are among men who have sex with men. The agency now publishes a monthly report specifically tracking this situation, which signals it expects this transmission chain to continue.

What could happen next?

Precedent
ECDC launching a dedicated monthly clade I surveillance bulletin marks the formal reclassification of clade I mpox from an imported exotic disease to a European endemic-transmission concern, with institutional monitoring consequences.
Risk
The reported 80-per-month clade I case plateau in early 2026 may undercount true incidence by two to four times in countries without systematic case-finding, based on diagnostic-infrastructure differences across reporting EU member states.

Source Landscape

This story draws on neutral-leaning sources

Primary parallel: The 2022 mpox clade IIb spread in Europe followed a similar entry pathway: imported cases among MSM, then local transmission confirmed in Spain, Germany and the UK, peaking at approximately 1,600 cases per week across the EU/EEA in August 2022 before declining as JYNNEOS vaccine uptake and behavioural change reduced transmission.

The structural difference with clade I is severity: clade IIb had a case-fatality rate below 0.1% in high-income countries; clade I's CFR in African outbreak settings runs 1-3% and likely 0.1-0.5% in European healthcare contexts with access to tecovirimat. ECDC's 'moderate' risk assessment for MSM reflects this severity gap.

Counter-parallel: The 2010-2015 re-establishment of hepatitis C in European MSM networks following initial containment illustrates the challenge of eliminating a blood-borne or contact-transmitted pathogen from a defined high-risk network without sustained prevention infrastructure.

Hepatitis C re-infection among MSM WHO had been treated persisted for a decade before direct-acting antivirals changed the equation. mpox clade I, absent an effective antiviral specifically for clade I and with JYNNEOS vaccine supply constrained, faces the same sustained-transmission risk.

Consensus view: ECDC's decision to launch a dedicated monthly mpox clade I bulletin formalises what the Centre's own rapid-risk assessments since late 2024 had been signalling: clade I is no longer an imported exotic finding in Europe but an established transmission chain within a specific population.

The Institut Pasteur (Paris) and UK Health Security Agency (UKHSA) both assess the 80-per-month plateau in February-March 2026 as evidence of endemic-level Community transmission among MSM in at least four EU countries, a qualitatively different situation from the 2022 clade IIb outbreak, which burned through a susceptible population and then declined. Clade I's higher severity profile means the moderate-risk assessment for MSM carries different weight than the 2022 low-severity signal did.

Counter-view: Paul Hunter (University of East Anglia, infectious disease epidemiology) and researchers at Belgium's Institute of Tropical Medicine have argued that the 80-per-month figure represents diagnosed and reported cases, likely undercounting true incidence by two to four times in countries without systematic contact-network surveillance.

The 'four countries with local transmission' figure understates geographic spread; it reflects which countries have robust enough diagnostic infrastructure to confirm local transmission, not which countries have it. ECDC's RAP threshold for MSM at 'moderate' could undercount true incidence in countries with thinner surveillance.

Key tension: Whether the 80-per-month plateau signals that clade I has found a stable transmission niche in European MSM networks (which would imply it is unlikely to decline without intervention) or whether it reflects genuine surveillance equilibrium around a stable, low-level ongoing chain that could break out if host immunity changes.

Sources:European Centre for Disease Prevention and Control

Mentions:ECDC →Spain →Italy →Portugal →Netherlands →Iceland →Paris →Germany →Norway →Belgium →mpox →UKHSA →

First Reported In

Update #8 · Ebola reaches France through a screening blind spot

European Centre for Disease Prevention and Control· 25 Jun 2026

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Causes and effects

Caused by

Mpox clade Ib now spreads in Europe

ECDC's new monthly mpox bulletin institutionalises monitoring of the clade Ib local European transmission first confirmed two weeks earlier.

Occurred 12 Jun 2026

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Mpox strain mixes genes from two clades

The recombinant clade Ib/IIb virus reported in late May is part of the same European mpox transmission landscape the new ECDC monthly report now covers.

Occurred 20 May 2026

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This Event

Europe starts a monthly mpox watch

The standing monthly bulletin is Europe's monitoring catching up to a transmission pattern its laboratories had already been tracking for months.

Led to

Europe's clade I mpox line goes flat

The monthly clade I bulletin ECDC launched in June is the series in which the flat June count appears.

Occurred 17 Jul 2026

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