Redesigning Isolation Practices: Evaluation of a Comprehensive Protocol for Respiratory Virus Control Including Cycle...

Area of Science:

• Infectious Diseases
• Virology
• Public Health

Background:

• Existing isolation guidelines for respiratory viruses are based on outdated transmission models.
• Recent literature challenges the droplet transmission hypothesis, emphasizing airborne and contact routes.
• There is a need for evidence-based revisions to optimize patient isolation protocols.

Purpose of the Study:

• To evaluate a new protocol for respiratory virus isolation, including personal protective equipment and air purification.
• To assess isolation relief criteria using Ct values from follow-up sampling.
• To determine the duration of viral shedding and infectivity for various respiratory viruses.

Main Methods:

• A novel isolation protocol was implemented and evaluated.
• Ct values were used as a proxy for viral replication and transmissibility (Ct < 28).
• Follow-up sampling was conducted on patients positive for RSV, HRV, hMPV, SARS-CoV-2, Influenza, and PIV.

Main Results:

• 25%-50% of patients with RSV, HRV, hMPV, or SARS-CoV-2 had high viral loads (Ct < 28) on day 7.
• Influenza and PIV showed faster viral clearance, with only 7% and 14% respectively having Ct < 28 on day 7.
• Discontinuing isolation without follow-up testing poses a risk of ongoing viral transmission for most studied viruses.

Conclusions:

• A standard 7-day isolation period without follow-up testing may be sufficient for influenza-positive patients.
• For other respiratory viruses like RSV, HRV, hMPV, and SARS-CoV-2, continued infectivity beyond 7 days is common.
• Revised isolation guidelines incorporating Ct value-based criteria are necessary to prevent nosocomial transmission.