New research update: Rethinking Downtime as a Biosecurity Measure

Introduction
Recent peer‑reviewed research from Ghent University has taken a fresh look at downtime - the common requirement for visitors or staff to avoid contact with livestock for 24–72 hours after visiting another farm. Although downtime is widely recommended in guidelines and legislation, this new review highlights a major gap between policy and scientific evidence.

Key Findings

No proven benefit beyond standard hygiene.

Across all available studies, downtime did not provide additional protection compared with well‑implemented hygiene measures such as:

• Handwashing

• Changing clothes and boots

• Showering before entry

Human nasal carriage of pathogens is possible but rarely infectious.

Some studies detected viral particles in people’s nasal passages after contact with infected animals, but viable, transmissible virus was extremely rare, and only one historical study showed possible transmission under artificial conditions.

Evidence is limited and species‑specific.

Most research focuses on pigs, with almost no controlled studies in poultry or ruminants, despite downtime being commonly required in these sectors.

Downtime may create a false sense of security.

Relying on downtime instead of verifying core hygiene practices could leave farms more vulnerable, especially if it reduces attention to proven measures.

What This Means for Your Farm
This review suggests that resources are better invested in enforcing and auditing practical hygiene protocols rather than imposing downtime restrictions that lack scientific support. Downtime may still help reduce unnecessary visitors, but it should not replace the fundamentals:

• Controlled entry points

• Proper hand hygiene

• Clean clothing and boots

• Shower‑in/shower‑out where applicable

• Clear visitor protocols and supervision

Bottom Line: Downtime alone does not meaningfully reduce disease risk.
Strong, consistent hygiene practices remain the most effective, and evidence‑based, tools for preventing indirect pathogen transmission.

If you’d like to read the article, you can find it here: Are Visitor and Personnel Downtime Restrictions an Effective Biosecurity Measure to Prevent the Indirect Transmission of Pathogens to Livestock?

For additional information on the rationale behind standdown periods, download the technical guide here.

Written by Hatch House Associate Veterinarian
Dr. Amira Mikhail BSc/DVM