title: Clinical characteristics of human monkeypox, and risk factors for severe disease.
abstract: BACKGROUND
  Human monkeypox is an emerging smallpox-like illness that was identified for the first time in the United States during an outbreak in 2003. Knowledge of the clinical manifestations of monkeypox in adults is limited, and clinical laboratory findings have been unknown.
  
  
  METHODS
  Demographic information; medical history; smallpox vaccination status; signs, symptoms, and duration of illness, and laboratory results (hematologic and serum chemistry findings) were extracted from medical records of patients with a confirmed case of monkeypox in the United States. Two-way comparisons were conducted between pediatric and adult patients and between patients with and patients without previous smallpox vaccination. Bivariate and multivariate analyses of risk factors for severe disease (fever [temperature, > or =38.3 degrees C] and the presence of rash [> or =100 lesions]), activity and duration of hospitalization, and abnormal clinical laboratory findings were performed.
  
  
  RESULTS
  Of 34 patients with a confirmed case of monkeypox, 5 (15%) were defined as severely ill, and 9 (26%) were hospitalized for >48 h; no patients died. Previous smallpox vaccination was not associated with disease severity or hospitalization. Pediatric patients (age, < or =18 years) were more likely to be hospitalized in an intensive care unit. Nausea and/or vomiting and mouth sores were independently associated with a hospitalization duration of >48 h and with having > or =3 laboratory tests with abnormal results.
  
  
  CONCLUSIONS
  Monkeypox can cause a severe clinical illness, with systemic signs and symptoms and abnormal clinical laboratory findings. In the appropriate epidemiologic context, monkeypox should be included in the differential diagnosis for patients with unusual vesiculopustular exanthems, mucosal lesions, gastrointestinal symptoms, and abnormal hematologic or hepatic laboratory findings. Clinicians evaluating a rash illness consistent with possible orthopoxvirus infection should alert public health officials and consider further evaluation.
authors.affiliation: Epidemic Intelligence Service, Division of Applied Public Health Training, Epidemiology Program Office, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30329-4018, USA.
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Huhn
authors.forename: Audrey M
authors.initials: AM
authors.lastname: Bauer
authors.forename: Krista
authors.initials: K
authors.lastname: Yorita
authors.forename: Mary Beth
authors.initials: MB
authors.lastname: Graham
authors.forename: James
authors.initials: J
authors.lastname: Sejvar
authors.forename: Anna
authors.initials: A
authors.lastname: Likos
authors.forename: Inger K
authors.initials: IK
authors.lastname: Damon
authors.forename: Mary G
authors.initials: MG
authors.lastname: Reynolds
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Kuehnert
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D045908:Mpox, Monkeypox / Q000175:diagnosis*; D012307:Risk Factors; D012720:Severity of Illness Index