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Infectivity of severe acute respiratory syndrome during its incubation period

Guang Zeng1, Shu-Yun Xie, Qin Li

  • 1Chinese Field Epidemiology Training Program, Chinese Center for Disease Control and Prevention, Beijing 100050, China. zeng4605@vip.sina.com

Biomedical and Environmental Sciences : BES
|March 27, 2010
PubMed
Abstract

Insights

Severe acute respiratory syndrome (SARS) is not infectious during the incubation period. Only symptomatic SARS patients transmit the virus, guiding updated medical isolation protocols for close contacts.

Area of Science:

  • Infectious Diseases
  • Epidemiology
  • Virology

Background:

  • Understanding the transmission dynamics of Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) is crucial for effective public health interventions.
  • Previous protocols for medical isolation during the SARS outbreak were based on assumptions about infectivity during the incubation period.

Purpose of the Study:

  • To evaluate the infectivity of SARS during its incubation period.
  • To provide scientific evidence for updating medical isolation protocols.

Main Methods:

  • Investigated transmission chains and individuals under medical observation in Beijing during the 2003 SARS outbreak.
  • Conducted questionnaire surveys on close contacts of SARS patients and those developing symptoms.
  • Performed serological tests (neutralization test, ELISA) for SARS-CoV antibodies on exposed individuals.

Main Results:

  • Out of 1112 investigated contactors, 101 (15.1%) developed symptoms after close contact with symptomatic SARS patients.
  • None of the 363 individuals with close contact to patients in their incubation period developed symptoms (0%).
  • SARS-CoV antibodies were detected in symptomatic individuals but not in asymptomatic contacts.

Conclusions:

  • SARS cases are infectious only when symptomatic, not during the incubation period.
  • Medical isolation should focus on close contacts of symptomatic SARS patients.
  • Findings are critical for defining SARS close contacts and refining public health policies.

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