Antiviral disinfectants are critical tools in safeguarding public health, particularly in high-risk environments like hospitals, schools, food processing facilities etc. The ability of these products to inactivate viruses on surfaces significantly reduces the chance of a viral outbreak  but the effectiveness of these products must be rigorously tested and validated. We explore the key test methods for the antiviral disinfectant efficacy testing, as well as the relevant regulations.

Importance of Antiviral Disinfectants

The antiviral disinfectants inactivate the virus by breaking its structure thus making them non-infectious and consequently arresting the spread of diseases such as COVID-19, influenza, norovirus etc. They are very important in real-world conditions for the control of viral contamination of frequently touched surfaces and helping reduce the occurrence of viral diseases. However, if disinfectants are to perform their duties as claimed, they have to meet strict efficacy standards which must be tested before they are released to the market.

Role of Testing in Ensuring Efficacy

Testing protocols identify whether antiviral disinfectants work against viruses in an artificial environment. Testing confirms that a product will perform as expected under certain conditions. Manufacturers and end-users need to be very sure that a product will do exactly what it has been designed to do. 

Key Regulations Governing Antiviral Disinfectant Testing

International and National Standards

Several international and national standards govern antiviral disinfectant efficacy testing. The most prominent ones are the European Standards (EN), the protocols set by the U.S. Environmental Protection Agency (EPA), and ISO standards.

1.EN 14476 – This European Standard evaluates the virucidal activity of disinfectants tested against viruses such as Poliovirus, Adenovirus, norovirus and vaccinia virus. A disinfectant should lead to at least 4 log or 99.99% reduction in the virus titer to be considered effective.

• EN 13610 : 2002 – Determination of virucidal activity of disinfectant used in food, industrial, and domestic areas against bacteriophages.

• EN 17122 : 2019 – Evaluation of the virucidal activity of chemical disinfectants or antiseptics used in veterinary areas.

2.EPA Protocols – Disinfectant registration in the USA is regulated by the EPA under FIFRA. Disinfectants are required to pass very stringent testing to show efficacy against a particular virus, such as Influenza or Norovirus among others.

3.ISO Standards – ISO standards provide guidelines on the test methodology so that consistency is maintained at the international level.

• ISO 18184 : 2019 – Evaluation of Antiviral activity of textile products.

• ISO 21702 : 2019 – Determination of antiviral activity on plastics and other non-porous surfaces.

These standards help ensure that antiviral disinfectants are tested for high thresholds of efficacy and safety and that results are consistent across different markets.

Test Methodologies and Protocols

Several key test methodologies make up the foundation of antiviral disinfectant testing, simulating different environments and use cases. Suspension tests, surface tests, and carrier tests are all conducted to determine the antiviral disinfectant efficacy under various conditions.

Suspension Tests

Suspension tests measure the disinfectant’s ability to inactivate viruses in a liquid medium. The viruses are suspended in a solution and exposed to a disinfectant  for a definite contact time under controlled conditions. For antiviral disinfectant efficacy testing, products must show significant viral reduction as per the relevant standard.

According to the EN 14476 protocol for instance, disinfectants are required to show a minimum of 4 log reduction in viral activity. This is equivalent to inactivating at least 99.99% of a virus in suspension by a product.

Surface Tests

Surface tests involve the application of a disinfectant to surfaces, typically stainless steel or plastic, artificially contaminated with viruses. Such tests are very relevant in places like hospitals or public areas where there is always the chance of surface contamination. The disinfectant should be effective in reducing the viral population after a contact time. 

Carrier Tests

Carrier tests are used to determine the antiviral activity of a disinfectant applied to porous materials, such as textiles or wipes. This type of antiviral disinfectant efficacy testing is conducted to simulate how well a disinfectant will work after impregnation into a material and thus helps guarantee that a product—in this case, wipes or treated fabrics—really serves to lower viral contamination.

Factors Influencing Testing Outcomes

Different factors influence the actual test results associated with antiviral disinfectants. Awareness of such factors is necessary for a proper product appraisal to be carried out.

Contact Time

Another factor related to the efficiency of the product is the contact time. Most tests stipulate the contact time required by the disinfectant to remain on the surface to bring the level of inactivation to the desired level. This means that shorter contact times may show reduced efficacy, and longer times, quite often, give improved performance. These are some of the nuances that form a part of ensuring the outcome of antiviral disinfectant efficacy testing. 

Active Ingredient Concentration

Another critical factor is the active ingredient concentration in the disinfectant formulation. Although a higher concentration generally means improved efficacy, it may also be associated with safety risks or damaging the sensitive surfaces. Testing protocols are finalized to ensure that the product keeps a fine balance between efficacy and safety.

Environmental Conditions

Temperature, humidity, and pH levels are environmental factors that influence the efficacy of antiviral disinfectants. Disinfectant testing takes these factors into account to make sure the products are competitive under a range of conditions.

Challenges in Antiviral Disinfectant Testing

Despite the standardized testing protocols, several challenges persist in ensuring accurate and consistent results for antiviral disinfectants.

Virus Variability

Viruses differ significantly in their structure and resistance to disinfectants. For instance, enveloped viruses like Influenza are generally more susceptible to disinfectants compared to the non-enveloped ones like Norovirus. The protocols for antiviral disinfectant efficacy testing has to include representative strains of different viruses that vary significantly.

Real-World Application

While laboratory experiments are conducted within controlled environments, real-life conditions can always add more variables. For instance, available organic matter or dirt can hamper a disinfectant’s efficiency. More complex methods for testing to simulate the worst-case real-world condition are important to confirm the efficacy of the disinfectants.

Regulatory Differences

Regulations on antiviral disinfectants differ from one country to another and from one region to another. For manufacturers of disinfectants aiming to enter the global market, this necessitates adapting to diverse international standards and regulatory requirements for efficacy testing, thereby increasing both the cost and complexity of product validation. Consequently, antiviral disinfectant efficacy testing becomes a critical component for achieving successful compliance on a global scale.

Viral infection control is dependent on the efficacy of antiviral disinfectants. The disinfectants have to be subjected to some form of standardized testing protocol for effectiveness. A number of test methods are available, such as suspension, surface, and carrier tests which provide manufacturers with tools to test the efficacy of their products under different conditions.

International standards like EN standards, EPA protocols, and ISO standards offer benchmarks for antiviral disinfectant testing thus ensuring that products meet global efficacy and safety standards. Contact us for rigorous testing protocols from our laboratories Microbe Investigations Switzerland (MIS), we specialize in validating disinfectant efficacy for various applications.