Mpox Terminology and Guidelines

Mpox (monkeypox) is a viral zoonosis (a virus transmitted to humans from animals) with symptoms similar to those seen in the past in smallpox patients, although it is clinically less severe. With the eradication of smallpox in 1980 and subsequent cessation of smallpox vaccination, Mpox has emerged as the most important orthopoxvirus for public health. Mpox primarily occurs in central and west Africa, often in proximity to tropical rainforests, and has been increasingly appearing in urban areas. Animal hosts include a range of rodents and non-human primates. Source: WHO

2022 Mpox Outbreak

Since early May 2022, cases of Mpox have been reported from countries where the disease is not endemic, and continue to be reported in several endemic countries. Most confirmed cases with travel history reported travel to countries in Europe and North America, rather than West or Central Africa where the Mpox virus is endemic. This is the first time that many Mpox cases and clusters have been reported concurrently in non-endemic and endemic countries in widely disparate geographical areas. Most reported cases so far have been identified through sexual health or other health services in primary or secondary health-care facilities and have involved mainly, but not exclusively, men who have sex with men. Source: WHO

2022 U.S. Map & Case Counts

Signs & Symptoms

Mpox is a rare disease caused by infection with the Mpox virus. Mpox virus is part of the same family of viruses as smallpox. Mpox symptoms are similar to smallpox symptoms, but milder; and Mpox is rarely fatal. Mpox is not related to chickenpox. Symptoms of Mpox can include:

• Fever
• Headache
• Muscle aches and backache
• Swollen lymph nodes
• Chills
• Exhaustion
• A rash that can look like pimples or blisters that appears on the face, inside the mouth, and on other parts of the body, like the hands, feet, chest, genitals, or anus.

The rash goes through different stages before healing completely. The illness typically lasts 2-4 weeks. Sometimes, people get a rash first, followed by other symptoms. Others only experience a rash. Source: CDC

Vaccines

NIAID provided significant support in the development of the JYNNEOS™ (also known as Imvamune or Imvanex) vaccine to prevent Mpox and smallpox. The vaccine was developed for people with weakened immune systems who were at risk for severe side effects from the existing smallpox vaccines. The JYNNEOS vaccine is an attenuated (weakened) live virus vaccine approved by the U.S. Food and Drug Administration in 2019 for individuals at high risk for smallpox or Mpox infection. Source: NIAID

Treatment

Currently, there is no specific treatment approved for Mpox virus infection. However, there are antiviral medications that can be used to treat smallpox and other conditions that may help patients with Mpox infection. NIAID supported the development of two of these smallpox treatments—tecovirimat or ST-246 (TPOXX), made by SIGA Technologies, New York, and brincidofovir (Tembexa), manufactured by Chimerix, based in Durham, N.C. NIAID is screening other novel compounds to find potential antiviral candidates to treat Mpox and is working to conduct larger clinical testing of tecovirimat specifically to treat patients with Mpox virus disease. Source: NIAID

Note: MPX is an emerging, rapidly evolving situation.