By Lynn L. Bergeson and Carla N. Hutton

The U.S. Department of Agriculture (USDA) announced on April 11, 2023, that its Agricultural Research Service (ARS) recently developed sustainable, machine-washable antimicrobial wipes that can be used at least 30 times for cleaning hard and nonporous surfaces. According to USDA, ARS researchers developed the antimicrobial wipes “by using raw cotton fiber that naturally produced silver nanoparticles inside the fiber in the presence of a silver precursor.” USDA states that the embedded silver nanoparticles then release silver ions that act as antibacterial agents and kill harmful bacteria. USDA notes that in their research, scientists found that the wipes killed 99.9 percent of harmful bacteria S. aureus and P. aeruginosa on surfaces.

USDA states that the advantages to this technology include omitting the conventional pretreatments of raw cotton fibers (such as scouring and bleaching), which consume a large number of chemicals and energy, and not requiring any chemical agents except for a silver precursor. According to USDA, the technology “also transforms cotton fibers themselves into antimicrobial agents rather than serving as a carrier of antimicrobial agents, which is what makes them reusable.” USDA notes that the antimicrobial wipes are made from “natural cotton fibers, rather than conventional petroleum-based synthetic fibers.” The wipes can be reused by being washed in the laundry.

More information on the antimicrobial wipes is available in an article in Molecules entitled “Washable Antimicrobial Wipes Fabricated from a Blend of Nanocomposite Raw Cotton Fiber.”

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By Dana S. Lateulere and Barbara A. Christianson

On October 19, 2022, the U.S. Environmental Protection Agency (EPA) announced that it activated its emerging viral pathogen (EVP) guidance in support of the Centers for Disease Control and Prevention’s (CDC) response to the Ebola virus cases in western Uganda. With EPA’s EVP guidance, additional disinfectants, for which EVP claims have been approved, can be used against the Ebola virus.

According to EPA’s press release, EPA developed its EVP guidance to aid in the availability of EPA-registered disinfectants for use against EVPs. EPA states that it divides viruses into three tiers based on how difficult they are to kill. The Ebola virus falls into Tier 1, the category of viruses that are easiest to kill. EPA expects disinfectants qualified for use against any EVPs in Tiers 1, 2, and 3 to be effective against the Ebola virus when used according to the label use directions.  To find these products, EPA recommends searching its list of disinfectants and filter for products for use on Tier 1 viruses.

EPA states the use of products with EVP claims supplements but does not replace other infection control practices. Individuals should follow CDC, state, and local public health guidelines.

According to EPA, EPA’s website “provides the list of products registered for use against Ebola, and list of disinfectants for emerging viral pathogens.”

Additional information on EVP guidance is available on our blog.

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By Heather F. Collins, M.S.

The U.S. Environmental Protection Agency (EPA) announced on May 26, 2022, that on Monday, May 23, 2022, it has activated its Emerging Viral Pathogen (EVP) Guidance for Antimicrobial Pesticides (Guidance) in response to monkeypox, which had been considered to be a rare disease caused by infection with the monkeypox virus. According to the U.S. Centers for Disease Control and Prevention (CDC), monkeypox was first discovered in 1958 when two outbreaks of a pox-like disease occurred in colonies of monkeys kept for research, hence the name “monkeypox.” The first human case of monkeypox was recorded in 1970 in the Democratic Republic of Congo during a period of intensified effort to eliminate smallpox. CDC states that its scientists are tracking multiple cases of monkeypox that have been reported in several countries that do not normally report monkeypox, including the United States.

EPA developed its Guidance in 2016 to address emerging pathogens. Under this Guidance, EPA provides pesticide registrants with a voluntary “two-stage process to enable use of certain EPA-registered disinfectant products against emerging viral pathogens not identified on the product label.” These pathogens may not be identified on a label because the occurrence of EVPs is less common and predictable than that of established pathogens and because the pathogens are often unavailable commercially and standard methods for laboratory testing may not exist. EPA’s intent is for the Guidance to “expedite the process for registrants to provide useful information to the public” regarding products that may be effective against EVPs associated with certain human or animal disease outbreaks. Registrants with a pre-qualified EVP designation can include an efficacy statement in technical literature distributed to health care facilities, physicians, nurses, public health officials, non-label-related websites, consumer information services, and social media sites. Additional information on the EVP Guidance is available here and here.

The monkeypox virus belongs to the Orthopoxvirus genus in the family Poxviridae and is an enveloped virus, meaning it is one of the easiest to kill with the appropriate disinfectant product. EPA recently developed the new List Q: Disinfectants for Emerging Viral Pathogens (EVPs). Monkeypox virus is a Tier I (enveloped virus); thus, when disinfectants damage their lipid envelope, the virus is no longer infectious. EPA’s List Q currently has 422 disinfectant products for use on Tier 1 viruses.

The EVP Policy for the monkeypox virus expires in May 2023.

Information on the monkeypox virus is available on CDC’s website.

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By Barbara A. Christianson

On November 19, 2021, the U.S. Environmental Protection Agency (EPA) announced that it is extending COVID-19 activation of the emerging viral pathogens (EVP) guidance for antimicrobial pesticides indefinitely. EPA states that its EVP guidance for antimicrobial pesticides is a part of the federal government’s pandemic preparedness, allowing manufacturers to provide EPA with data, even in advance of an outbreak, demonstrating that their products are effective against hard-to-kill viruses.

EPA activated its EVP guidance for antimicrobial pesticides for the first time in January 2020 in response to the emergence of SARS-CoV-2. EPA has allowed for expedited review and approval of surface disinfectant products for use against SARS-CoV-2 for more than 12 months, including accelerated review for products seeking to add EVP claims to product labels. To date, EPA has added 591 products with emerging viral pathogens claims to its list of Disinfectants for Coronavirus (List N).

EPA states that registrants must remove EVP claims from consumer messaging no later than 24 months after the original notification of the outbreak, unless directed otherwise by EPA. With this extension, EPA will now provide a notification at least six months before inactivating the EVP guidance for SARS-CoV-2 to allow registrants time to adjust product marketing materials as required.

Additional information on the EVP guidance is available here.

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By Heather F. Collins, M.S. and Barbara A. Christianson

On October 15, 2021, the U.S. Environmental Protection Agency (EPA) announced that it has revised its guidance for evaluating the efficacy of antimicrobial pesticides against Candida auris (C. auris). EPA states that pesticide manufacturers seeking to register their products with a C. auris claim should use this updated guidance to test the effectiveness of the products against a drug-resistant strain of C. auris.

EPA states that C. auris is an emerging, multidrug-resistant yeast (a type of fungus). It can cause serious infections and spreads easily among hospitalized patients and nursing home residents. C. auris can spread in healthcare settings through contact with contaminated environmental surfaces or equipment, or from person to person. According to the Centers for Disease Control and Prevention (CDC), more than one in three patients with an invasive (e.g., affecting the blood, heart, or brain) C. auris infection die.

In 2017, in consultation with the CDC, EPA issued interim guidance for testing the effectiveness of hospital disinfectants against C. auris. Subsequently, based on input from the CDC on its tracking of clinical cases of multi-drug resistant C. auris isolates in the United States, the laboratory data were generated to ensure antimicrobial efficacy against a more relevant strain of the pathogen.

Working closely with experts from the CDC, EPA conducted a comparative evaluation of isolates and found that the drug-resistant isolates were more tolerant to some disinfectant treatments. Since a drug-resistant isolate (AR Bank #0385) is highly relevant to current outbreaks in the United States, it is considered a suitable test microbe for regulatory purposes.

The guidance provides recommendations for laboratory methodology on how to:

1. produce and store cultures of drug-resistant C. auris, and
2. evaluate the effectiveness of antimicrobial products intended to treat surfaces contaminated with drug-resistant C. auris.

Under the updated guidance, all new products seeking registration with claims against C. auris should test for efficacy using the more relevant strain (AR Bank #0385). Efficacy testing using AR Bank #0381 is acceptable in some cases where the study initiation date is between October 15, 2020, and October 15, 2021. For study initiation dates between October 15, 2020, and October 15, 2021, EPA will accept studies conducted with isolate AR Bank #0381 for products whose active ingredients are either sodium hypochlorite or hydrogen peroxide plus acetic acid. For products with other active ingredients, it will be necessary to retest using isolate AR Bank #0385.

Existing antimicrobial products with C. auris claims based on the previous strain (AR Bank #0381) will be allowed to retain their claim of effectiveness against C. auris. To claim effectiveness against drug-resistant C. auris, EPA requires retesting with the more relevant strain (AR Bank #0385) identified in the updated guidance and according to the revised test method.

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By Heather F. Collins, M.S. and Barbara A. Christianson

On September 15, 2021, the U.S. Environmental Protection Agency (EPA) announced that it is terminating the Temporary Amendment to Pesticide Registration (PR) Notice 98-10, effective September 15, 2022. EPA states that it is providing 12 months’ notice to registrants before the termination takes effect to give registrants time to adjust their contractual commitments. Registrants must ensure that by September 15, 2022, their product is produced using a source of active ingredient identified in the product’s EPA-approved Confidential Statement of Formula (CSF) or otherwise complies with the requirements of PR Notice 98-10. All notifications submitted to EPA under the temporary process are valid only for the time period of the temporary amendment. After September 15, 2022, registrants “will not be able to release for shipment formulations produced under the conditions of the temporary amendment without first complying with the registration requirements that were in place prior to the issuance of the temporary amendments.”

EPA states that this notice applies to products on EPA’s List N: Disinfectants for Use Against SARS-CoV-2 (the virus that causes COVID-19) or products that serve as the source of active ingredient for disinfectants on EPA’s List N. This notice also applies to food contact surface sanitizer products containing the active ingredient isopropyl alcohol that are used in the essential role of food manufacturer and preparation.

In 2020, EPA issued temporary amendments to PR Notice 98-10 to ensure that antimicrobial products remained available in response to the COVID-19 public health emergency. According to EPA, supply chains have stabilized and disinfectant products expected to kill SARS-CoV-2 have become consistently available to consumers, so it has determined that this flexibility is no longer needed. When the temporary amendment was issued, EPA stated it would assess the continued need for and scope of the temporary amendment to PR Notice 98-10 on a regular basis and would update it if EPA determined modifications were necessary. EPA stated it would post a notification at www.epa.gov/pesticides at least seven days prior to terminating the temporary amendment. EPA acknowledges in the termination memorandum that registrants require time to make the temporary changes permanent through CSF amendment or notification and therefore is providing 12 months, rather than the seven days guaranteed in the temporary amendment.

The memorandum addressing the termination is available here. Information on the temporary amendments to PR Notice 98-10 are available on our blog.

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By Lisa M. Campbell, Heather F. Collins, M.S., and Barbara A. Christianson

On December 10, 2020, the U.S. Environmental Protection Agency (EPA) announced a new policy that will allow registrants of antimicrobial pesticide products voluntarily to disclose all inert ingredients more efficiently in response to the request of retailers, states, and industry.

Registrants who wish to disclose all inert ingredient can choose to do so in three ways under the new policy:

• On the product label as part of the full ingredient statement or on the product’s back or side panel with a referral to the full ingredient statement;
• On a website referenced on the product label; or
• On a website that is not directly linked to the product label.

EPA states that it will allow registrants to use alternate nomenclature to disclose inert ingredients.  This policy is effective as of January 16, 2021. 

EPA states that there is no statutory or regulatory requirement to identify inert ingredients in the ingredient statement, except when EPA determines that such inert ingredients may pose a hazard to humans or the environment.  EPA states that if EPA determines an inert ingredient may pose a hazard, EPA may determine that the name of the inert ingredient must be listed in the ingredient statement on a case-by-case basis for either risk-based or hazard-based reasons.  Examples include the following ingredients:

• Petroleum distillates, xylene, or xylene range aromatic solvents > 10%;
• Sodium nitrate > 0.1%; or
• Inert ingredients of toxicological concern (formerly known as “List 1 Inerts”).

EPA’s long-standing policy, as stated in its Label Review Manual, has been that “if a registrant wants to list a particular inert ingredient in the ingredient statement, the registrant should list all inert ingredients directly below the ingredient statement in descending order by weight. A partial listing on the label could be misleading.”  EPA’s new policy applies to voluntary identification of inert ingredients using alternate nomenclature and not to cases where EPA directs registrants to list particular inert ingredients because of risk-based or hazard-based reasons.

EPA states that beginning December 15, 2020, the Office of Pesticide Programs (OPP) will review antimicrobial pesticide applications for voluntary inert ingredient disclosure.  Under this new process, EPA states that if a registrant chooses to utilize alternate chemical nomenclature on its product labeling, the registrant must resubmit the Confidential Statement of Formula (CSF) containing the inert ingredient as approved on the existing formulation as well as the alternate chemical nomenclature.  EPA requires that a “crosswalk” between the approved nomenclature of the CSF and the alternate nomenclature be provided with the registrants’ non-Pesticide Registration Improvement Extension Act (PRIA 4) application, which will fall under a 90-day review.

If registrants choose to use alternate nomenclature, EPA encourages using the following sources:

• EPA Inerts List;
• International Union of Pure and Applied Chemistry (IUPAC);
• Chemical Abstracts Service (CAS); or
• Consumer Product Ingredient Database Directory.

If a registrant chooses to disclose voluntarily inert ingredients on the label, the registrant should list all of the inert ingredients directly below the ingredient statement in descending order by weight, so that the list does not interfere with the required labeling information.  If space is limited, however, to avoid crowding of required labeling information, a referral statement may be used directing the reader to the back or side panel for the full list of inert ingredients in descending order by weight.  The referral statement should be placed directly below the ingredient statement with an asterisk or some other equivalent symbol connecting the “Inert Ingredients” or “Other Ingredients” heading in the ingredient statement with the full list of inert ingredients placed on the back or side panel of the label.  For example, an acceptable referral statement is “*See back panel for complete inert ingredient statement,” and acceptable corresponding text on the back panel is “*Inert Ingredients:  Inert A, Inert B., etc.”

When registrants choose to add a website address or quick response (QR) code to their labeling that leads to inert ingredient information, EPA asks that registrants, in a cover letter transmitting the labeling amendment application, self-certify that the inert ingredient information provided on the registrant’s website(s) and in other marketing materials is consistent with the information provided on the latest approved CSF.

EPA states that registrants do not need to amend its their master label or notify EPA before adding an inert ingredient statement to a website, provided that the site is not referenced on the product label.  In such cases, the application process outlined below does not apply.

EPA states that no other actions should be included with inert ingredient disclosure applications.  The following information is required to be included in the application:

• Applications to add alternate nomenclature to the label must:
  • Crosswalk link the current CSF nomenclature to any alternate nomenclature as confirmation that the current CSF nomenclature and alternate nomenclature are synonyms of each other (the exact same inert ingredient).  EPA provides a template spreadsheet for the alternate nomenclature crosswalk to link the current CSF nomenclature to any alternate inert ingredient nomenclature.
  • Identify in the cover letter the proposed changes to the alternate nomenclature on product labels and CSFs, the revised CSF (which includes the current and alternate nomenclature) and master label with changes highlighted.
  • For applications to add currently approved nomenclature to the label registrants should include with the application a cover letter identifying the proposed change(s) on product labels and master label with changes highlighted, including the following self-certification statement: “The inert ingredients voluntarily disclosed in the labeling for EPA Registration No. [add registration number], are accurate for the EPA-registered product listed above. No changes to the product formulation have been made. I certify that no other changes have been made to the labeling of this product. I understand that it is a violation of 18 U.S.C. 1001 to willfully make any false statement to EPA. I further understand that if the information I have provided is misbranded as defined in section 2(q) of FIFRA, 7 U.S.C. 136(q), this product may be in violation of FIFRA and EPA may pursue enforcement actions under sections 12 and 14 of FIFRA, 7 U.S.C. 136(j) and 136(l).”
• For applications to add or change a website or QR code to include inert information, applicants must include a cover letter that identifies the proposed change(s) on product labels and master label with changes highlighted, including the following self-certification statement: “The inert ingredients voluntarily disclosed in the labeling for EPA Registration No. [add registration number], are accurate for the EPA-registered product listed above. No changes to the product formulation have been made. I certify that no other changes have been made to the labeling of this product. I understand that it is a violation of 18 U.S.C. 1001 to willfully make any false statement to EPA. I further understand that if the information I have provided is misbranded as defined in section 2(q) of FIFRA, 7 U.S.C. 136(q), this product may be in violation of FIFRA and EPA may pursue enforcement actions under sections 12 and 14 of FIFRA, 7 U.S.C. 136(j) and 136(l).”

According to EPA, the scope of this policy is currently limited to antimicrobial pesticide products.  EPA states that it may consider expanding to conventional pesticide and biopesticide products in the future.

Additional information is available here.

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By Barbara A. Christianson

On October 26, 2020, the U.S. Environmental Protection Agency (EPA) announced that it is soliciting public comment on the interim guidance on registering products that claim to have “residual” or “long-lasting” effectiveness against viruses.  This announcement follows up on EPA’s October 14, 2020, announcement that it would begin expediting its review of products with residual efficacy intended for use against SARS-CoV-2, the coronavirus that causes COVID-19.  While traditional disinfectants only kill viruses and bacteria that are on the surface at the time they are used, surfaces treated with residual antimicrobial products kill pathogens that come into contact with the surface days, weeks, or years after the product is applied.

EPA announced in an October 26, 2020, memorandum that it is seeking feedback from the public on the expedited process, design elements for evaluating residual product claims, and the test methods associated with this initiative. 

All comments on the interim guidance must be submitted to Docket Number EPA-HQ-OPP-2020-0529 on or before January 4, 2021. 

The interim guidance documents -- Interim Method for Evaluating the Efficacy of Antimicrobial Surface Coatings, Interim Guidance - Expedited Review for Products Adding Residual Efficacy Claims, and Interim Method for the Evaluation of Bacterial Activity of Hard, Non-Porous Copper-Containing Surface Products -- are available in Docket Number EPA-HQ-OPP-2020-0529.  More information on the interim guidance is available on our blog.

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By Lisa M. Campbell, Heather F. Collins, M.S. and Barbara A. Christianson

On October 14, 2020, the U.S. Environmental Protection Agency (EPA) released a much-anticipated draft guidance that will allow companies to demonstrate that their products have “long-lasting” or “residual” effectiveness on surfaces against viruses like SARS-CoV-2, the coronavirus that causes COVID-19.  EPA’s guidance specifies scientific testing requirements for two different types of products:  (1) disinfectants that also provide residual efficacy, and (2) supplemental residual antimicrobial products (e.g., coatings, paints, solid surfaces) that do not meet EPA’s standards for disinfectants but are intended to be used as a supplement to standard List N disinfectants.

In addition to releasing the draft residual efficacy protocols, EPA has also released an updated draft testing protocol for evaluating a copper surface’s ability to kill bacteria and a draft protocol for evaluating the efficacy of antimicrobial surface coatings.  These laboratory testing methods act as a foundation for EPA’s interim guidance to registrants regarding residual effectiveness.

While EPA does not have an approved standard method to support virus claims for these types of products, EPA states that the following information is intended to provide interim guidance on the study design elements necessary to support these types of claims.  EPA states that it may consider other methods or studies to support residual efficacy claims, provided they are scientifically sound.  Applicants are highly encouraged to consult with EPA prior to submitting.  Of significant interest, EPA states that products may make both types of residual claims provided that they are supported by the appropriate data.

Due to lab capacity concerns, EPA plans to consider non-GLP (Good Laboratory Practice) data to support residual claims, provided that the study submission accurately represents how the study differs from the GLP standards in the 40 C.F.R. Section 160.12 statement of non-compliance.  Additional details provided in the EPA guidance on how to qualify products for residual disinfectants or supplemental residual antimicrobial products are briefly outlined below.

Residual Disinfectant Claims

Residual disinfectants must clear a higher standard of efficacy than supplemental residual antimicrobial products.  Residual disinfectant products must be effective within 10 minutes of a virus or bacteria contacting a treated surface and must remain effective for up to 24 hours.  Surfaces treated with residual disinfectants must not require additional cleaning or disinfection during this window.  EPA-approved residual disinfectant products are eligible to be added to List N.  In addition, long-lasting coating products must satisfy all requirements for standard disinfectant claims (non-residual) to be eligible for residual disinfectant claims and must have undergone testing to support standard disinfectant claims.

To support a claim as a residual bactericidal disinfectant, applicants should use EPA’s Residual Self-Sanitization Protocol with the following modifications:

• Base Bacteria -- Consistent with EPA Guideline 810.2200, Staphylococcus aureus (ATCC No. 6538) and Pseudomonas aeruginosa (ATCC No. 15442) should be used to support the case residual disinfectant claim.
• Conduct testing on three product lots at the lower certified limit (LCL) for each bacterium.  In accordance with the OCSPP 810.2000 Test Guideline, certificates of analysis should be submitted to substantiate the tested concentration.
• Residual testing to support additional vegetative bacteria is not needed.  Claims can be bridged from the standard disinfectant (non-residual data) for additional bacteria.  For example, if a product has data to support a base disinfectant claim (Staphylococcus aureus and Pseudomonas aeruginosa) and data to support disinfectant claims for additional vegetative bacteria (e.g., Escherichia coli or MRSA), residual data are only needed for the base bacteria, and not additional bacteria, to support residual claims for those vegetative bacteria for which base disinfectant claims are supported.
• According to the Residual Self-Sanitization Method, durability testing should include 12 wear cycles, consisting of abrasions (alternating wet and dry) and re-inoculations to support a 24-hour residual disinfectant claim.  Each wear cycle consists of four passes (two back and forth) of the abrasion material over the surface followed by re-inoculation.  Additional details can be found in the method.
• Products should achieve a ≥ 5-log reduction in ≤ 10 minutes ± 5 seconds for qualifying bacteria when compared to the parallel abrasion and re-inoculation controls to support residual disinfectant claims.
• According to the OCSPP 810.2200 Test Guideline, the performance standard and time to meet the performance standard are consistent with the standards for non-residual disinfectants.
• At this time, expedited review is limited to residual disinfection claims of 24 hours or less based on data generated in accordance with the re-inoculation and abrasion cycles specified in the referenced protocol.

1. Residual Virucidal Claims

EPA’s Residual Self-Sanitization Protocol with the modifications below should be used to support residual virucidal claims.  Virucidal efficacy should be assessed consistent with the principles of ASTM E1053 (e.g., recovery, cytotoxicity, neutralization, and calculations), the standard virucidal method detailed in OCSPP 810.2200 Product Performance Test Guideline.

• To support residual virucidal claims, acceptable non-residual virucidal efficacy (3-log reduction) should be demonstrated for the product at ≤ 10-minute contact time consistent with the OCSPP 810.2200 Product Performance Test Guideline.
• Residual virucidal data should be generated for the most difficult to kill virus that that the product claims to kill.  Claims for residual effect against the other viruses can be bridged from the non-residual virucidal data supporting the product.  For additional information on selecting the most difficult to kill virus, see EPA’s Emerging Viral Pathogens Guidance.
  • To be considered for List N, virus testing should include a non-enveloped virus or a human coronavirus (SARS-CoV-2 or human coronavirus 229E).
• Testing on two product lots should be conducted at the LCL.
• According to the Residual Self-Sanitization Method, durability testing should include 12 wear cycles consisting of abrasions (alternating wet and dry) and re-inoculations to support a 24-hour residual disinfectant claim.  Each wear cycle consists of four passes of the abrasion material over the surface followed by re-inoculation.  Additional details can be found in the method.
• Products should achieve ≥ 3-log reduction in ≤ 10 minutes ± 5 seconds for the hardest to kill virus when compared to the parallel abrasion and re-inoculation controls to support residual virucidal claims.
  • The performance standard and contact times are consistent with the standard non-residual disinfectants.
• At this time, expedited review is limited to residual disinfection claims of 24 hours or less based on data generated in accordance with the re-inoculation and abrasion cycles specified in the referenced protocol.

2. Labeling and additional information (both bactericidal and virucidal)

• Products are eligible for inclusion on List N following adherence to the Emerging Viral Pathogens guidance or appropriate testing for a qualifying virus (e.g., SARS-CoV-2 or human coronavirus 229E).
• These products may be used as stand-alone disinfectants and do not need a label disclaimer that they are a “supplement to standard disinfection” since they meet the general criteria for disinfectants (effective in ≤ 10 minutes with appropriate log reductions for bacteria and virus).

Supplemental Residual Antimicrobial Products

Supplemental residual antimicrobial products work within two hours of a virus or bacteria coming into contact with a surface and can remain effective for weeks to years.  These products can supplement, but not replace, routine cleaning and disinfection using products from EPA’s List N:  Disinfectants for Use Against SARS-CoV-2 (COVID-19).  Approved supplemental residual antimicrobial products are not eligible for inclusion on List N, but will be added to a separate List N appendix.

Qualifying antimicrobial surface coatings, films, fixed/solid, and paint products should demonstrate efficacy against vegetative bacteria first before virus claims can be supported.  These products are not required to meet the efficacy standards for disinfectants and can only be approved for use as supplements to standard disinfection. The duration of residual effectiveness claims that EPA will consider for expedited review depends on the type of product, as outlined below.

1. Antimicrobial Surface Coatings and Films

For these products, EPA states that EPA’s draft Performance of Antimicrobial Surface Coatings on Hard Non-porous Surfaces for qualifying bacteria should be used.  EPA provides the following additional information for products on which virus claims would be added:

• Test Organisms
  • Bacteria -- Staphylococcus aureus (ATCC No. 6538) and Pseudomonas aeruginosa (ATCC No. 15442) are the qualifying bacteria required to support supplemental residual antimicrobial surface claims for the proposed claim duration (e.g., one week, two weeks).
    • Testing should be conducted on three product lots per bacterium at the LCL.
  • To support claims for additional bacteria, testing should be conducted according to the method but with a reduced number of product lots.
    • Two lots of product for each bacterium at the nominal concentration.
  • Viruses -- All viruses for which claims are desired should be tested.  The most difficult to kill virus should be subjected to the durability assessment using coating carriers followed by the efficacy assessment to support the proposed duration (e.g., one week, two weeks).  All other viruses should be tested using coated carriers that were not subjected to the durability procedure.
    • Assessment of virucidal efficacy on the coated carriers should be conducted consistent with ASTM E1053, the standard method specified in EPA’s 810.2200 Efficacy Test Guideline.
    • Two lots of product at the LCL should be tested for the most difficult to kill virus.  Two lots of product at the nominal concentration should be tested for additional viruses.
      • To be considered as a supplement to List N, virus testing should include a non-enveloped virus or a human coronavirus (SARS-CoV-2 or human coronavirus 229E).
• Stainless steel carriers will be used to support claims for coatings on hard, nonporous surfaces.  Use sites should be limited to hard, non-porous surfaces.  Additional material types (e.g., porous materials or textiles) may be proposed by the registrant upon consultation with EPA prior to submission.
• The recommended number of abrasions (touches) and cycles of exposure to cleaning or disinfecting chemicals are provided in the method to substantiate durability claims.  The method also specifies the chemical disinfecting solutions to simulate cycles of in-service disinfection and cleaning.  Additional details can be found in the method.
  • Ten cycles of abrasion and/or chemical exposure is equivalent to one week of durability.  The number of cycles can be increased in one-week increments to support claims up to four weeks.
  • If a product is incompatible with one or more of the test chemistries, this should be discussed with EPA in advance and may limit use sites and surfaces depending on the nature of the incompatibility.  EPA does not have a standard method for determining incompatibility.  This may be based on research and development data or known incompatibilities with the coating material, for example.
• This protocol may be modified for films upon consultation with EPA in advance of submission.
• If an applicant intends to claim supplemental residual effects longer than four weeks, it should consult with EPA in advance of submission.  EPA states that because the ongoing antimicrobial integrity of coatings and films will not be readily visible, it is important that end users have a reasonable expectation of durability.
• Products should achieve a 99.9% reduction (3-log) for both bacteria and viruses in comparison to untreated controls within a maximum of two hours but not less than one hour, as EPA is concerned that observations taken before the inoculum has dried (e.g., less than one hour) on the surface may not provide an accurate assessment of the product.
  • The time to achieve performance begins at the time of inoculation.

2. Antimicrobial Surface Coatings and Films -- Labeling and Additional Information

EPA states that this new category of antimicrobial products should be labeled as supplemental residual antimicrobial surfaces.  EPA provides the following additional information:

• As these products do not meet the criteria for a disinfectant due to the longer contact time and lower performance standard, claims for residual disinfectant are not acceptable.  As above, contact times for disinfectants are ≤ 10 minutes and with a higher performance standard for bacteria.
• Products should carry the following prominent label qualifier that they are a supplement to standard disinfection and cleaning:
  • “Although this product DOES NOT meet EPA’s standards for disinfectants, EPA has determined that, when used with an EPA-registered disinfectant, this product can provide some additional protection against [microorganism(s)] for up to X days. This product DOES NOT achieve the same level of efficacy as an EPA-registered disinfectant; it is only intended to provide supplemental protection between routine applications of EPA-registered disinfectants.”
• For products eligible only for supplemental residual antimicrobial claims, EPA intends to require as a term of registration that the label and labeling state, “This product does not meet EPA’s efficacy standards to qualify as a stand-alone disinfectant.”
• Although these products will not be eligible for List N, they will be eligible as a supplement to List N (N.1) to reflect that they are supplemental treatments (i.e., not stand-alone disinfectants) and intended for use in combination with List N disinfectants.
• The following are example acceptable product label claims:
  • “Kills 99.9% of [insert microorganism/s] within two hours of exposure when used as part of a comprehensive infection control program/protocol for up to X days.”
  • “Continuously reduces [insert microorganism/s] within two hours of exposure when used as part of a comprehensive infection control program for up to X days.”

3. Fixed/Solid Surfaces Including Solid Copper and Other Metals and Solid Impregnated Materials and Paints -- Method Recommendation

EPA states that these products should use EPA’s Draft Copper Surface Protocol for qualifying bacteria.  EPA provides the following additional information for products that wish to have virus claims added.

• Test Organisms
  • Bacteria -- Staphylococcus aureus (ATCC No. 6538) and Pseudomonas aeruginosa (ATCC No. 15442) are the qualifying bacteria used to support supplemental residual surface claims.
    • Testing should be conducted on three product lots per bacterium at the LCL.
  • To support claims for additional bacteria, testing should be conducted according to the method but with a reduced number of product lots.
    • Two lots of product for each bacterium at the nominal concentration.
  • Viruses -- All viruses for which claims are desired should be tested.  The most difficult to kill virus should be subjected to the durability assessment in the copper method, followed by the efficacy assessment.  All other viruses should be tested using test carriers that were not subjected to the durability procedure.
    • Assessment of virucidal efficacy on the coated carriers should be conducted consistent with ASTM E1053, the standard method specified in EPA’s 810.2200 Efficacy Test Guideline.
    • Two lots of product at the LCL should be tested for the most difficult to kill virus.  Two lots of product at the nominal concentration should be tested for additional viruses.
• The recommended number of abrasions (touches) and cycles of exposure to cleaning or disinfecting chemicals are provided in the method in order to substantiate durability claims.  The method also specifies the chemical solutions to simulate cycles of disinfection and cleaning.
  • As the durability of these types of products can be readily observed, duration claims are not necessary.  This is consistent with currently registered copper-containing surface products and paints.
  • If a product is incompatible with one or more of the test chemistries, this should be discussed with EPA in advance and may limit use sites and surfaces, depending on the nature of the incompatibility.  EPA states that it does not have a standard method for determining incompatibility.  This may be based on research and development data or known incompatibilities with the coating material, for example.
• This protocol can be modified for other metals or solid impregnated surfaces or paints upon consultation with EPA.
• Products should achieve a 99.9% reduction (3-log) for both bacteria and viruses in comparison to untreated controls within two hours.
  • The time to achieve performance begins at the time of inoculation.

4. Fixed/Solid Surfaces Including Solid Copper and Other Metals and Solid Impregnated Materials and Paints -- Labeling and Additional Information

EPA states that these products should be labeled as supplemental residual antimicrobial surfaces.  EPA states the following with regard to these products:

• As these products do not meet the criteria for a disinfectant due to the longer contact time and lower performance standard, claims for residual disinfectant are not acceptable.
• Products should carry the following prominent label qualifier that they are a supplement to standard disinfection and cleaning:
  • “Although this product DOES NOT meet EPA’s standards for disinfectants, EPA has determined that, when used with an EPA-registered disinfectant, this product can provide some additional protection against [microorganism(s)] for up to X days. This product DOES NOT achieve the same level of efficacy as an EPA-registered disinfectant; it is only intended to provide supplemental protection between routine applications of EPA-registered disinfectants.”
• For products eligible only for supplemental residual antimicrobial claims, EPA intends to require as a term of registration that the label and labeling should state, “This product does not meet EPA’s efficacy standards to qualify as a stand-alone disinfectant.”
• Although these products will not be eligible for List N, they will be eligible as a supplement to List N (N.1) to reflect that they are supplemental treatments (i.e., not stand-alone disinfectants) and intended for use in combination with List N disinfectants.  The following are example acceptable product label claims:
  • “Kills 99.9% of [insert microorganism/s] within two hours of exposure when used as part of a comprehensive infection control program/protocol.”
  • “Continuously reduces [insert microorganism/s] within two hours of exposure when used as part of a comprehensive infection control program.”

5. Supplemental Residual Antimicrobial Products -- Stewardship Program

EPA intends to require, as a term of registration, that registrants of all supplemental residual antimicrobial products prepare and implement a written stewardship plan designed to support the responsible use of supplemental residual coatings and antimicrobial surface products.  Unlike conventional antimicrobial products, EPA believes that these products represent unique challenges that require timely feedback to ensure proper use and compatibility in combination with current infection control practices.  EPA expects that plans would be submitted for EPA review and approval during the registration process, or shortly thereafter (e.g., within two months after the registration date).  An approvable plan would address the proper sale (including advertising and promotional materials), distribution, and responsible use of the supplemental residual coatings and antimicrobial surface products.  EPA states that plans should include, at a minimum, the following elements:

• Advertising and promotional materials that clearly and consistently include a disclaimer that the product does not meet EPA’s standards for disinfectants and is intended to supplement the use of EPA-registered disinfectants.
• Outreach to the infection control community;
• Customer feedback consisting of product issues/concerns, adverse events, compliance challenges/observations, and contraindications/adverse events gathered through quarterly registrant-initiated surveys, customer complaints, and suggestion boards; and
• Development of a stewardship website.

EPA states further that “if EPA determines at any time following registration that the Plan is not being adequately or timely implemented or does not effectively ensure the product’s safe and effective use, the registration may be cancelled by the Agency.”  It is not clear from the statement whether EPA intends such a cancellation to be a term of the registration or whether it would be undertaken pursuant to the standard FIFRA cancellation procedures.

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By Lynn L. Bergeson, Lisa M. Campbell, and Carla N. Hutton

On October 14, 2020, the U.S. Environmental Protection Agency (EPA) released much-anticipated draft guidance that will allow companies to demonstrate that their products have “long-lasting” or “residual” effectiveness on surfaces against viruses like SARS-CoV-2, the coronavirus that causes COVID-19.  As most know, EPA has not before now provided guidance on how stakeholders can demonstrate to EPA’s satisfaction that their product remains efficacious for periods of time, given the broad diversity of contact opportunities and scenarios.  Importantly, EPA states that pursuant to Title VII of the Coronavirus Aid, Relief, and Economic Security (CARES) Act, it is providing notice of its intention to expedite reviews for addition of residual (i.e., extended or long-lasting) efficacy claims for currently registered or new product registrations that are on EPA’s Disinfectant List N, that would qualify for List N, or products that can be used as a residual supplement to disinfectants on List N.  The guidance specifies scientific testing requirements for two different types of products, supplemental residual antimicrobial products and residual disinfectants.  According to EPA, supplemental residual antimicrobial products work within two hours of a virus or bacteria coming into contact with a surface and can remain effective for weeks to years.  EPA notes that these products can supplement, but do not replace, routine cleaning and disinfection using products from EPA’s List N:  Disinfectants for Use Against SARS-CoV-2 (COVID-19).  Approved supplemental residual antimicrobial products are not eligible for inclusion on List N, but EPA will add them to a separate List N appendix.

In addition to releasing the draft residual efficacy protocols, EPA has also released an updated draft testing protocol for evaluating a copper surface’s ability to kill bacteria and a draft protocol for evaluating the efficacy of antimicrobial surface coatings.  According to EPA, “[t]hese laboratory testing methods act as a foundation for EPA’s interim guidance to registrants regarding residual effectiveness.”

More information will be available in a forthcoming memorandum that will be available on our website.

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