Instituto Valenciano de Microbiología
(IVAMI)

Masía El Romeral
Ctra. de Bétera a San Antonio Km. 0.3
46117 Bétera (Valencia)
Phone. 96 169 17 02
Fax 96 169 16 37
Email: 
www.ivami.com
CIF B-96337217

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Measurement of antiviral activity on plastics and other non-porous surfaces (ISO 21702: 2019).

Recently, porous and non-porous products treated with antivirals have also been commercialized. The determination of the antibacterial activity incorporated in non-porous products or in porous products (textiles) is carried out according to ISO 22196 and ISO 20743, respectively. For antiviral activity incorporated into textile products, there was the ISO 18184: 2014 standard, later replaced by the new version of the standard. The new ISO 21702 standard indicates the method of testing antiviral activity in non-porous products. As the standard itself indicates, the method described is based on the standards for products with antibacterial activity ISO 22196 and for products with antiviral activity ISO 18184. The standard ISO 21702 is intended for application to products such as plastics, coating materials, ceramics, natural and artificial leathers, stainless, rubber, etc., that is, plastics and other non-porous surfaces.

Due to the individual sensitivities of each virus to antivirals, the results obtained with a test virus cannot be applied to other viruses. The standard indicates the use of two viruses, one of them relatively susceptible, Influenza A (H3N2) virus (A/Hong Kong/8/68 H3N2) and another more resistant, Feline Calicivirus. However, the standard itself indicates that other viruses can be used as alternatives by indication of the manufacturers. In our laboratory we can use any of the viruses proposed by other ISO, EN or ASTM standards (see virus list included in this information), or other viruses when they can be obtained from culture collections.

In the tests, pieces of the material with antiviral activity and pieces without antiviral activity (negative controls) are used. These pieces are inoculated on their surface with the viral suspension, covered with a foil, and left to incubate at 25ºC and 90% relative humidity for 24 hours, or shorter up to 24 hours, if requested by the manufacturer. Three (3) pieces should be used in each of the test groups, although more pieces can be used if you want to reduce the variability in the results, especially with products that have little antiviral activity. Controls of both, pieces with antiviral and pieces without antiviral are used in the tests to demonstrate that they have no effect that can reduce the infectivity of the virus or the susceptibility of the cells to infectivity by the virus, and at the same time to immediately quantify the virus deposited as inoculum on them. After the contact time, the deposited viruses are collected and quantified, to determine, where appropriate, the reduction obtained in the pieces with antiviral activity, compared to the pieces without antiviral activity. The results are expressed in titer (quantity) of virus per cm2 of sample tested. The standard does not establish a criterion to consider the effectiveness of the product, which leaves to consensus criterion between the parties involved (manufacturers, users, ...).

The tests are carried out using square pieces of 50 ± 2 mm x 50 ± 2 mm and equal or less than 10 mm thick, both of material with antiviral activity and without antiviral activity (controls). Nine (9) pieces of material with antiviral activity and 12 pieces without antiviral activity (negative controls) are required for each virus chosen. For the main tests they will be carried out using at least three samples of each test material treated. At least twelve samples of the untreated material and nine samples of treated material are required.

Cost of tests with viruses recommended by this and other standard guidelines (ISO, EN, ASTM):

Cost of test with other viruses not recommended by EN standard guidelines