Identifying Paucisymptomatic or Asymptomatic and Unrecognized Ebola Virus Disease Among Close Contacts Based on...

Area of Science:

• Infectious Diseases
• Epidemiology
• Public Health

Background:

• Limited evidence exists for screening algorithms to detect asymptomatic or paucisymptomatic Ebola virus (EBOV) infection and unrecognized Ebola virus disease (EVD).
• Effective identification strategies are crucial for controlling EVD transmission.

Purpose of the Study:

• To evaluate screening algorithms using rapid diagnostic testing (RDT) and exposure assessments for identifying contacts with asymptomatic or unrecognized EVD.
• To determine the utility and trade-offs of sequential screening strategies.

Main Methods:

• A cohort study classified contact-participants based on serostatus and postexposure symptoms into uninfected, paucisymptomatic/asymptomatic infection, or unrecognized EVD groups.
• Exposure risk was categorized as low, intermediate, or high.
• Hypothetical scenarios evaluated the World Health Organization (WHO) case definition with or without RDT and exposure assessments.

Main Results:

• Of 1909 contacts, 115 (6%) had paucisymptomatic/asymptomatic EBOV infection, and 107 (6%) had unrecognized EVD.
• High-risk exposures significantly increased the odds of unrecognized EVD (aOR, 3.5).
• Sensitivity for identifying unrecognized EVD was high with RDT (96%) and intermediate- to high-risk exposures (97%), with low false-positive rates for RDT (2%).

Conclusions:

• Sequential screening algorithms incorporating RDT and exposure risk assessments are valuable for identifying contacts with unrecognized EVD.
• These strategies demonstrate utility and trade-offs in detecting asymptomatic or unrecognized EVD cases.
• The findings support enhanced surveillance and contact tracing protocols for EVD.