In May 2022, the World Health Organization (WHO) made an emergency announcement of the existence of a multi-country outbreak of mpox, a viral disease then commonly known as "monkeypox".

The disease had been circulating and evolving in human hosts over several years before the outbreak and was caused by the clade IIb variant of the virus.

[13] A global response to the outbreak included public awareness campaigns in order to reduce spread of the disease, and repurposing of smallpox vaccines.

The disease can spread through direct contact with rashes, or body fluids from an infected person, by touching objects and fabrics that have been used by someone with mpox or through respiratory secretions.

[26] The Centers for Disease Control and Prevention has emphasized the importance of reducing stigma in communicating about the demographic aspects of mpox, specifically with regards to gay and bisexual men.

[30] On 17 March 2021, the Nuclear Threat Initiative led a tabletop exercise at the Munich Security Conference simulating hypothetical public health responses to the intentional release of a genetically manipulated strain of monkeypox virus.

[37][38] In a 2021 article, Oyewale Tomori pointed out that the number of mpox infections in Nigeria through 2021 were likely to be under-reported, because many Nigerians had been avoiding healthcare facilities due to fear of contracting COVID-19.

[39] Nigeria's surveillance of various diseases, including mpox, had to focus on the global COVID-19 pandemic in 2020 and 2021, missing many cases and resulting in a drop in official statistics.

[55][56] An analysis of studies by a journalist in August 2022 indicated that "about 10-to-15% of cases had been hospitalized, mostly for pain and bacterial infections that can occur as a result of mpox lesions".

[59] A short review suggested supportive care may typically be sufficient and that several antivirals and vaccinia immune globulin intravenous (VIGIV) are available as treatments.

[61] In May 2022, the UK Human Animal Infections and Risk Surveillance (HAIRS) group[62] warned that the virus could reach wildlife and become endemic as a result.

[65] In August, the first known case of probable human-to-dog transmission was reported with the canine exhibiting very similar signs and symptoms of mpox infection to that of humans.

Mpox infection was immediately suspected, and the patient was hospitalised at a specialist clinical unit of the Guy's and St Thomas' NHS Foundation Trust[44] and isolated, then tested positive for the virus on 6 May.

[67] Following this contact tracing effort, the World Health Organization (WHO) considered further transmission of the virus within the United Kingdom to be of "minimal" risk.

A "small number" of people in Scotland were ordered to self-isolate following close contact with the person initially reported to have been infected, although overall risk to the general public remained "very low".

[74] The UK Health Security Agency (UKHSA) advised people who have had close contact with a person infected with mpox to self-isolate for 21 days.

[95] On 23 May, David Heymann, an advisor for the World Health Organization, said that the likely theory of how the outbreak started is transmission during sexual intercourse of gay and bisexual men at two raves in Belgium and Spain.

[97] In addition to more common symptoms, such as fever, headache, swollen lymph nodes, and rashes or lesions, some patients have also experienced proctitis, an inflammation of the rectum lining.

CDC has also warned clinicians to not rule out mpox in patients with sexually transmitted infections since there have been reports of co-infections with syphilis, gonorrhea, chlamydia, and herpes.

It is transmitted by close contact with infected people, with extra caution for those individuals with lesions on their skin or genitals, along with their bedding and clothing.

The disease can spread via respiratory secretions or by direct contact with rashes, body fluids or by touching objects and fabrics that have been used by someone with mpox.

According to the centre, among MSM who contracted the virus, the most common means of transmission is likely through sexual activity due to intimate contact with infectious skin lesions.

[125] A study from the Faculty of Medicine at Chulalongkorn University reported multiple traces of monkeypox virus were detected in non-sewered wastewater with sparse sampling collected from both the Bangkok, Thailand with increasing concentrations from June to August 2022.

On 24 May, Centers for Disease Control (CDC) Deputy Director Jennifer McQuiston confirmed the United States is releasing some of their Jynneos vaccine supply from their Strategic National Stockpile for people who are "high-risk".

[150] In August 2024, though, the Japanese government decided to send donations of the vaccine to the Democratic Republic of the Congo to help in their mitigation efforts.

[156] On 25 May, the World Health Organization released several statements and pamphlets aimed at gay and bisexual men describing the symptoms of mpox, as well as possible transmission routes.

[158] On 30 July, Rod Dreher of The American Conservative criticized public health officials for not shutting down gay sex clubs in response to the outbreak.

"[160][161] An August survey by the CDC found that gay and bisexual men have significantly reduced sexual encounters in response to the mpox outbreak.

[168] On 20 May, the World Health Organization (WHO) convened an emergency meeting of independent advisers to discuss the outbreak and assess the threat level.

[7][170] Its European chief, Hans Kluge, expressed concern that infections could accelerate in Europe as people gather for parties and festivals over the summer.