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European health officials are warning that they have identified a concerning type of mpox virus spreading locally in four countries. The announcement follows the discovery of similar mpox cases spreading locally in California.
The European Centre for Disease Prevention and Control (ECDC), in a public alert issued Friday, said that locally acquired cases of a type of clade I mpox virus have been identified in Spain, Italy, Portugal, and the Netherlands.
It is the first time this type of mpox has been detected spreading within the European Union and European Economic area, the health agency said. Previously, cases of this form of the virus were associated with international travel outside the region.
Outbreaks of clade I mpox have been ongoing in parts of Central and Eastern Africa.
There are two types of mpox, clade I and clade II, and both are spread through close, intimate and sexual contact and cause potentially painful rashes. During 2022-23, outbreaks across the United States involved the milder clade II type of the virus, which continues to circulate here at low levels.
The clade I type of the virus has the potential to cause more severe disease, health officials have said.
While an mpox vaccine provides protection against both the clade I and clade II virus, Healthbeat reported last week that federal data show in most U.S. states, more than half of people at highest risk of mpox infections were not vaccinated in the wake of the 2022-23 outbreaks.
Here are four takeaways from the ECDC’s new alert.
Clade I mpox has been detected spreading locally in Europe
The ECDC says cases of mpox clade I have been spreading locally in European countries, rather than just being brought in by travelers.
Spain reported its first locally acquired clade I case on Oct. 10. The Netherlands reported a case on Oct. 17. Since then, two cases were reported in Italy and one in Portugal. The patients started showing symptoms between Sept. 16 and Oct. 7.
Among these five patients, all men, none had any history of travel to countries with known transmission of clade I mpox. Of the four patients whose vaccination status was known, only one was vaccinated against mpox.
“These new cases have been reported among men, some of whom identify themselves as men who have sex with men, with no recent travel history to mpox-endemic areas,” the ECDC said. “This indicates that transmission may be ongoing in sexual networks among men who have sex with men in European countries.”
In its alert, the ECDC noted that local transmission of clade Ib cases has also been detected in California among gay, bisexual, and other men who have sex with men and their social networks.
European risk assessment says more cases are likely to be identified
An mpox threat assessment, also released Friday by the ECDC, said the overall risk of mpox clade I infection in Europe is “moderate for men who have sex with men and low for the general population.”
But the agency noted there is “substantial uncertainty” about the extent of transmission within sexual networks. “In general, the likelihood of exposure is higher with a higher number of casual sexual partners, which is supported by historical data from the mpox outbreak in 2022/23,” the assessment said.
The assessment said it is likely there are additional mpox clade I cases that have not yet been detected.
The severity of locally spread clade I mpox is unclear
While the three recent clade I cases identified in California all required hospitalization, the ECDC said the five European cases all had mild symptoms.
Clade I mpox is divided into two subtypes: clade Ia and clade Ib. The recently identified European and California cases are all clade Ib mpox, the ECDC said.
According to the U.S. Centers for Disease Control and Prevention, infections with clade 1a mpox, especially among children younger than 15, have occurred in Central Africa through contact with infected dead or live animals and through household transmission or patient care.
Clade Ib was more recently identified as spreading through intimate and adult sexual contact.
The ECDC, in its health alert Friday, said: “Some uncertainties remain regarding the transmissibility and clinical severity of clade Ib” compared to the clade II virus that has circulated since the 2022-23 outbreaks.
Before the recent locally transmitted clade I cases were identified, there had been 29 travel-related clade I cases reported to the ECDC, with seven of them needing hospitalization. But the agency said it is difficult to estimate the severity of disease based on such small numbers.
The ECDC said the severity of clade I infections may be worse among those living with HIV, especially if they are receiving inadequate treatment. People with other underlying health conditions, including suppressed immune systems, and people over the age of 65, may also be at increased risk for severe disease.
Awareness, vaccination can protect against mpox
Both the clade I and clade II types of mpox cause a rash that may look like pimples or blisters. The rash, which may involve a few lesions or many, can appear on any part of the body, including the hands, face, mouth, chest, or near genitals.
Mpox may also cause flu-like symptoms. The virus is usually spread through close contact, such as skin-to-skin contact and during sex, health officials say.
“If an unusual rash develops, they should seek medical help by contacting a health care professional for testing and advice. It is also important to avoid close physical or sexual contact with others until they are symptom-free,” the ECDC said.
Vaccination is the best protection against both clade I and clade II, health officials in Europe and the United States said.
The mpox vaccine in the United States, called JYNNEOS, is available through retail pharmacies, usually with advance appointments, as well as through clinics, health care providers, and public health departments. Locations that may offer the vaccine can be found at: www.EmpoweredAgainstMpox.com.
The ECDC has called for European countries to ensure lab testing is easily accessible, especially in locations that serve men who have sex with men, and that those at higher risk are advised to get vaccinated.
Alison Young is Healthbeat’s senior national reporter. You can reach her at ayoung@healthbeat.org or through the messaging app Signal at alisonyoungreports.48
