03/15/2024: Lab Advisory: Guidance for Specimens and Clinical Waste Suspected to Contain Clade I Monkeypox Virus

CDC's Laboratory Outreach Communication System (LOCS)

Audience: Clinical Laboratory Professionals

Level: Laboratory Advisory

While the risk for Clade I mpox cases in the U.S. remains low and there are currently no cases in the U.S., several federal agencies are working to improve readiness in the event of a Clade I mpox outbreak.

The U.S. Department of Transportation (DOT) has released a Safety Advisory Notice regarding the classification of monkeypox virus (MPXV) specimens and waste, which addresses the transportation and disposal of material suspected or confirmed to contain MPXV. This notice clarifies that samples and clinical waste from both Clade I and II MPXV are designated as Category B infectious substances. Only Clade I viral cultures — i.e., materials containing or contaminated with intentionally propagated virus — of Clade I MPXV should be designated as Category A infectious substances. Clinical laboratories should not culture samples suspected of Clade I MPXV. If a laboratory inadvertently cultures Clade I MPXV, see select agent information below including destruction of material.

Waste can be packed, transported, treated/inactivated, and disposed as United Nations (UN) 3291, Regulated Medical Waste (RMW) under the Hazardous Material Regulations (HMR) and any applicable state, tribal, local, or territorial regulations — the same way other waste from healthcare facilities is routinely managed.

Laboratory specimens (excluding cultured Clade I MPXV) can be packed and shipped as Category B infectious substances (UN 3373, Biological Substance, Category B). Specimens suspected to contain only Clade II MPXV do not require a DOT Special Permit.

Categorization of MPXV under the HMR is different from select agent status under federal select agent regulations. MPXV (where the clade is undetermined) and MPXV Clade I remain on the U.S. Department of Health and Human Services (HHS) select agent list and are subject to applicable HHS/Centers for Disease Control and Prevention (CDC) requirements at 42 CFR 73. Clade II MPXV is excluded from the federal select agent regulations under 42 CFR 73.3(d)(12).

A select agent or toxin that is contained in a diagnostic or verification specimen or sample is exempt from the requirements of the select agent regulations for that specific select agent or toxin if you do the following:

  • Unless directed otherwise by the Federal Select Agent Program (FSAP), within seven (7) calendar days after identification of the select agent or toxin, either transfer the select agent or toxin in accordance with Section 16 of the select agent regulations (requires prior approval by FSAP) or destroy the select agent or toxin on-site by a recognized sterilization or inactivation process.
  • Secure the select agent or toxin to prevent theft, loss, or release before transfer or destruction.
  • Report the identification of the select agent or toxin.
  • Maintain copies of all APHIS/CDC Form 4A reports for a period of (3) three years.

Refer to CDC’s Division of Select Agents and Toxins (DSAT) Select Agent (SA) Gram (12/21/2023) for reporting requirements for the identification of Clade I MPXV.

If MPXV (where the clade is undetermined using a generic MPXV assay) or MPXV Clade I is identified in a sample, transfer of those samples must be preauthorized by FSAP using the APHIS/CDC Form 2 (APHIS/CDC Form 2: Request to Transfer Select Agents and Toxins). This includes samples containing MPXV (either the clade is undetermined using a generic MPXV assay or are Clade I) but have not been cultured. The preauthorization requirement is not impacted by the allowance by DOT to ship non-cultured clinical samples as Category B infectious substances.

Destruction of select agent material may be done on-site by a recognized sterilization or inactivation process. For information on inactivation for nonregistered laboratories that identify a select agent, including Clade I MPXV, refer to https://selectagents.gov/compliance/faq/inactivation.htm.

Chemical disinfection procedures are available using an EPA-registered hospital-grade disinfectant with an emerging viral pathogen claim. Products with Emerging Viral Pathogens claims may be found on EPA’s List Q. Follow the manufacturer’s directions for concentration, contact time, and care and handling for inactivating virus.

Sterilization procedures can be used to inactivate virus if using an autoclave operating within permitted parameters as outlined by the manufacturer and validated by the operator.

We encourage you to share this message widely with your network(s).

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The Laboratory Outreach Communication System

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Center for Laboratory Systems and Response (CLSR)

Centers for Disease Control and Prevention (CDC)