Confirmed and Suspected Cases



  • Monkeypox is a zoonotic disease caused by a Poxvirus known as monkeypox virus.
  • Monkeypox disease results in a smallpox-like disease in humans although it is less severe than smallpox. In general, symptoms begin with fever, headache, muscle pains and feeling tired.
  • Monkeypox is usually a self-limited disease with the symptoms lasting from 2 to 4 weeks.
  • A rash usually appears 1–3 days after the onset of fever and lymphadenopathy, with lesions appearing simultaneously, and evolving at a similar rate. Their distribution is mainly peripheral but can cover the whole body during a severe illness.
  • Human-to-human transmission is relatively inefficient, and this can result from close contact with respiratory secretions, skin lesions of an infected person or recently contaminated objects.
  • In general, outbreaks occur occasionally in sub-Saharan Africa after someone comes in contact with an infected wild animal, and infected travelers sometimes carry the disease to other countries.

Monkeypox virus

The virus is closely related to smallpox and vaccinia viruses. Smallpox vaccination was approximately 85% protective against monkeypox

Two distinct genetic clades of the monkeypox virus: the West African clade and the Central African (Congo Basin) clade.

The West African clade demonstrates a case fatality rate (CFR) <1%, and no human-to-human transmission was documented previously.

The Central African clade shows a CFR up to 11% and causes more severe disease and human-to-human transmission.

Current Outbreaks of Monkeypox

Monkeypox outbreaks have been reported in over 60 countries globally.

Current global outbreaks are caused by the West African clade. It is not clear if they represent mutant strains with increased transmissibility or pathogenicity.

Most of the cases have lesions exclusively perigenital, perianal, and around the mouth.

Almost all of the cases include men aged 20–50, many of whom are gay, bisexual and have sex with men.

It is unclear whether sexual transmission is a contributing factor to current outbreak. One of the hypotheses is its transmission after close contact with lesions.

Available Vaccines

ACAM2000: similar to the vaccine used during the smallpox eradication campaign.

Jynneos: a nonreplicating form of vaccinia and explicitly approval for monkeypox.



  • Nature. Monkeypox goes global: why scientists are on alert. https://www.nature.com/articles/d41586-022-01421-8
  • Shchelkunov SN, Marennikova SS, Moyer RW. Orthopovxiruses Pathogenic for Humans. Chapter: Classification of Poxviruses and Brief Characterization of the Genus. New York, NY: Springer (2005)
  • Ladnyi ID, Jezek Z, Fenner F, Henderson DA, Arita I. Smallpox and its Eradication Chapter: Human Monkeypox and Other Poxvirus Infections of Man. Geneva: World Health Organization (1988).
  • Fine PE, Jezek Z, Grab B, Dixon H. The transmission potential of monkeypox virus in human populations. Int J Epidemiol. 1988; 17(3):643–650.
  • Bunge EM, Hoet B, Chen L, Lienert F, Weidenthaler H, Baer LR, Steffen R. The changing epidemiology of human monkeypox-A potential threat? A systematic review. PLoS Negl Trop Dis. 2022 Feb 11;16(2):e0010141. doi: 10.1371/journal.pntd.0010141. PMID: 35148313; PMCID: PMC8870502.
  • Science. Monkeypox outbreak questions intensify as cases soar. https://www.science.org/content/article/monkeypox-outbreak-questions-intensify-cases-soar
  • Sklenovská N, Van Ranst M. Emergence of Monkeypox as the Most Important Orthopoxvirus Infection in Humans. Front Public Health. 2018 Sep 4;6:241.
  • Nature. Monkeypox goes global: why scientists are on alert. https://www.nature.com/articles/d41586-022-01421-8