The mpox virus can be categorised into two main groups: Clade 1 and Clade 2. In 2022, there was an mpox outbreak involving a virus variant from Clade 2. In 2024, there are multiple outbreaks of mpox in West and Central Africa caused by Clade 1 mpox viruses, including outbreaks involving a new virus variant from Clade 1: mpox 1b. It emerged in the Democratic Republic of Congo (DRC) in September 2023. People have also become ill in the neighbouring countries of Burundi, Kenya, Rwanda and Uganda.

On 14 August 2024, the World Health Organisation (WHO) declared an international public health emergency in response to the mpox outbreak in the DRC and surrounding area. According to the WHO, a total of 14,000 infections and 526 deaths have already been reported in Central and West Africa this year. Some of these involve the new mpox variant 1b.

A case of mpox infection involving the new variant 1b was detected in Sweden on 15 August 2024. The patient had travelled to Central Africa recently. This is the first time that the new variant has been found outside Africa.

Situation in the Netherlands

There are no reports of infections involving mpox variant 1b in the Netherlands so far. RIVM is monitoring this situation closely, in close collaboration with doctors, Municipal Public Health Services (GGDs) and laboratories. Care providers are alert to people with symptoms. This will make it possible to identify infections quickly.

If a person has mpox, they must start self-isolating. This ensures that they avoid contact with others and cannot spread the virus. The GGD will start source and contact tracing.

It is currently very unlikely that the new mpox variant is spreading in the Netherlands. Close contacts of a person who has mpox can be vaccinated. The Netherlands has a sufficient supply of vaccines in stock. An antiviral drug is also available to treat possible complications.

If you think that you have mpox, contact your GP or the Municipal Public Health Services (GGDs).

Spread through close, intensive contact

The outbreaks of mpox in Africa involving the new variant seem to be mainly caused by close, intensive skin-to-skin contact between humans. The 2022 outbreak in Europe and North America occurred mainly among men who have sex with men (MSM contact). The outbreak in Central Africa affects a wider range of risk groups. Much is still unclear about this new mpox 1b variant, including how infectious it is.

Mpox infections in the Netherlands

The figure below shows the number of people with mpox reported in the Netherlands from 27 April 2022 through 22 August 2024.