The whole iceberg: estimating the incidence of yellow fever virus infection from the number of severe cases

Details

• Alternative Title:
  Trans R Soc Trop Med Hyg
• Personal Author:
  Johansson, Michael A. ; Vasconcelos, Pedro F. C. ; Staples, J. Erin
• Description:
  Background
  
  Like many infectious agents, yellow fever (YF) virus only causes disease in a proportion of individuals it infects and severe illness only represents the tip of the iceberg relative to the total number of infections, the more critical factor for virus transmission.
  
  Methods
  
  We compiled data on asymptomatic infections, mild disease, severe disease (fever with jaundice or hemorrhagic symptoms) and fatalities from 11 studies in Africa and South America between 1969 and 2011. We used a Bayesian model to estimate the probability of each infection outcome.
  
  Results
  
  For YF virus infections, the probability of being asymptomatic was 0.55 (95% credible interval [CI] 0.37– 0.74), mild disease 0.33 (95% CI 0.13–0.52) and severe disease 0.12 (95% CI 0.05–0.26). The probability of death for people experiencing severe disease was 0.47 (95% CI 0.31–0.62).
  
  Conclusions
  
  In outbreak situations where only severe cases may initially be detected, we estimated that there may be between one and seventy infections that are either asymptomatic or cause mild disease for every severe case identified. As it is generally only the most severe cases that are recognized and reported, these estimates will help improve the understanding of the burden of disease and the estimation of the potential risk of spread during YF outbreaks.
  
  
• Subjects:
  Bayes Theorem Disease Outbreaks Female Humans Incidence Male Yellow Fever Yellow Fever Virus
• Source:
  Trans R Soc Trop Med Hyg. 108(8):482-487
• Pubmed ID:
  24980556
• Pubmed Central ID:
  PMC4632853
• Document Type:
  Journal Article
• Funding:
  CC999999/Intramural CDC HHS/United States
• Place as Subject:
  Africa ; South America
• Volume:
  108
• Issue:
  8
• Collection(s):
  CDC Public Access
• Main Document Checksum:
  urn:sha256:0f6abf0a4507891409e6c44e7166d69dd5f26238422e7b6fedc7c6fc8ba9eb2c
• Download URL:
  https://stacks.cdc.gov/view/cdc/36408/cdc_36408_DS1.pdf
• File Type:
  [PDF - 345.86 KB ]