Early epidemiological assessment of the virulence of emerging infectious diseases: a case study of an influenza pandemic.

ABSTRACT:

Background

The case fatality ratio (CFR), the ratio of deaths from an infectious disease to the number of cases, provides an assessment of virulence. Calculation of the ratio of the cumulative number of deaths to cases during the course of an epidemic tends to result in a biased CFR. The present study develops a simple method to obtain an unbiased estimate of confirmed CFR (cCFR), using only the confirmed cases as the denominator, at an early stage of epidemic, even when there have been only a few deaths.

Methodology/principal findings

Our method adjusts the biased cCFR by a factor of underestimation which is informed by the time from symptom onset to death. We first examine the approach by analyzing an outbreak of severe acute respiratory syndrome in Hong Kong (2003) with k

SUBMITTER: Nishiura H 

PROVIDER: S-EPMC2729920 | biostudies-literature | 2009 Aug

REPOSITORIES: biostudies-literature