SARS (Severe Acute Respiratory Syndrome): Transmission and Infection Control

SARS Basics

SARS is caused by SARS-CoV, a coronavirus. The 2002–2003 outbreak affected 26 countries, with ~8,000 cases and 774 deaths (CFR ~9.6%).

Transmission Routes

• Direct droplet spread: Cough/sneeze → large droplets → mucosa of contacts within ~1–2 m.
• Indirect contact: Touching contaminated surfaces (fomites) → self-inoculation of eyes/nose/mouth.
• Aerosol-generating procedures: Intubation, bronchoscopy, CPR produce fine aerosols with longer range.
• Fecal-oral possible: Viral RNA in stool; implicated in Amoy Gardens apartment complex outbreak (plumbing aerosolization).

Infection Control Measures

• Standard + contact + airborne precautions for suspected cases.
• N95/FFP2+ respirators, eye protection, gowns, gloves.
• Negative-pressure isolation rooms.
• Rigorous hand hygiene and environmental disinfection (coronaviruses susceptible to standard disinfectants).
• Contact tracing and quarantine of exposed individuals.

Key Differences from SARS-CoV-2 (COVID-19)

• SARS-CoV: Lower transmissibility (R₀ ~2–3), higher CFR, peak viral shedding at day 7–10 (after symptom onset), minimal pre-symptomatic spread.
• SARS-CoV-2: Higher transmissibility, significant pre-symptomatic/asymptomatic spread, lower CFR.

No SARS cases reported since 2004. Surveillance continues for zoonotic coronaviruses.