China CDC Reports 1st Outbreak of Mpox Clade Ib

 

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Overnight China has announced that they have become the 12th country outside of Africa to report the emerging clade Ib Mpox virus. While many of these cases have been single, imported, cases - as we've seen recently in the UK and in Germany - this introduction has resulted in a cluster of locally acquired cases. 

It is not entirely clear where this case - or their contacts - reside.  Four major provinces/cities are mentioned in the response (Zhejiang, Guangdong, Beijing, and Tianjin). 

The clade Ib Mpox virus which emerged in late 2023 in the DRC is reportedly more virulent, and potentially more transmissible, than the clade II mpox virus which began its world tour in the spring of 2022.

First the Chinese CDC statement, after which I'll have a bit more.

A cluster outbreak of monkeypox virus subclade Ib was discovered in my country
Date: 2025-01-09

Recently, a cluster outbreak of monkeypox virus subclade Ib was discovered in my country. The source of infection was a foreigner with a history of living in the Democratic Republic of the Congo.

After the outbreak was discovered, the state and provinces (cities) such as Zhejiang, Guangdong, Beijing, and Tianjin quickly launched a joint prevention and control mechanism to carry out epidemiological investigation and tracing, risk investigation, case diagnosis and treatment, and other work.

Four related cases were found among close contacts, all of which were infected after close contact. The related cases mainly showed symptoms such as rash and herpes, and the symptoms were relatively mild. At present, no infected persons have been found among general contacts. The related infected persons and risk persons are receiving medical treatment and health observation, and the epidemic has been effectively handled.

Related link: Questions and answers on prevention and control of monkeypox virus subclade Ib

Earlier this week France reported their first imported case (see CIDRAP report), and in December the WHO published a new, updated risk assessment, which puts the risk of national and international spread as HIGH.

The Mpox virus continues to evolve, and we now have at least 4 clades of Mpox in circulation (I, Ib, II, IIb), with Clade Ia and Ib considered the most severe.

While the threat is limited for now, as our collective immunity from the smallpox vaccine - which was discontinued in the late 1970s - wanes, there are increased opportunities for pox viruses to make a comeback.