Textiles - Determination of antiviral activity of textile products (ISO 18184: 2019).

The global improvement in the standard of living makes consumers look for health protective products. The increase in people´s interest in protection against epidemic diseases, which protect them in crowded places with other people, such as occurs in public transport, hospitals, nursing homes, etc., along with advances in textile product processing technology, they have allowed the development of products with protective effects for health and hygiene. The textile product with antiviral properties is the result of the development of textile technology and biotechnology. Being relatively new products, the test methods developed to evaluate their properties were developed by the manufacturers themselves, so there was no unified test method, making it difficult for consumers and manufacturers to evaluate. Antiviral textile products are textiles capable of reducing the number of infectious virus particles that come in contact with the surface of the textile.

This has led to the need to establish an international standard to satisfy the need raised by consumers and manufacturers that could be applied to woven fabrics, fibers, yarns, braids, etc. The ISO 18184: 2019 standard specifies test methods for determining the antiviral activity of textile products against specific viruses. Due to the individual characteristics of each of the viruses, in terms of how they are affected by products incorporated into textile products, the results of a test virus cannot be extrapolated to other viruses.

The standard lists two viruses as an example, Influenza A H3N2 virus (A/Hong Kong/8/68/H3N2) and Feline Calicivirus, the first of them of considerable susceptibility, and the second of greater resistance, but it is indicated that other viruses can be used at the request of manufacturers. In IVAMI, the viruses chosen by the clients will be used, which in turn must be selected based on the antiviral activity expected by the manufacturer, taking into account that the most resistant viruses are those without envelopes (Poliovirus, Adenovirus, Norovirus), whereas enveloped viruses are more susceptible. As an example, we indicate that the EN 14476 standard, to consider a product as general virucidal, must show activity against Poliovirus, Adenovirus and Norovirus; that if the product shows activity only against Adenovirus and Norovirus, it is considered as virucidal with limited activity (with activity against Adenovirus, Norovirus, Rotavirus and enveloped viruses); and that if the product shows activity against Vaccinia virus, it is considered active only against enveloped viruses.

The standard gives two alternative methods to quantify the number of infectious viruses, which are the plaque formation method and the TCID50 method (Infectious Units for cell culture 50%). The standard leaves up to the laboratory to decide whether to use one or the other. At IVAMI, due to experience with tests carried out according to other internationally accepted standards (EN, ASTM, ISO), the quantification of viable viruses is used using the TCID50 procedure.

In the test, tissue pieces are used, both control (without incorporated antiviral) and the product under assay with incorporated antiviral, which are sterilized in an autoclave, or otherwise by the procedure indicated by the manufacturer, which are inoculated at various points with the chosen virus suspensión/s with a known TCID50 number (>107) and are maintained for a contact time of 2 hours (or up to a maximum of 24 hours) with the tissue pieces. After the contact period, the deposited viruses are eluted and the quantity of virus present is quantified. The standard does not establish a criterion for reducing the amount of virus to confirm that the product has antiviral activity, but only allows assigning a reduction value when compared to control tissues without incorporated antiviral. For this reason, all the appropriate controls must be available in the test, to confirm that the tissue does not contain elements that prevent the quantification of the virus in the inoculated cell cultures, by releasing substances that decrease the susceptibility of the cell cultures to infection by the virus. On the other hand, controls should be included to know the number of viruses deposited immediately after placing them on the tissues, and controls on both the tissue without antiviral, or with antiviral without inoculating with the virus suspensión/s.

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

  • Basic price with the two viruses indicated by the ISO 18184 standard (Influenza A H3N2 virus -A/Hong Kong/8/68 H3N2-) and Feline Calicivirus: consult to ivami@ivami.com.
  • Basic price with only one of the viruses indicated by the ISO 18184 standard (Influenza A H3N2 virus -A/Hong Kong/8/68 H3N2- or Feline Calicivirus: consult to ivami@ivami.com.
  • Basic Price with the three viruses obligates by the EN 14476 standard for general virucidal activity (Poliovirus type 1, Adenovirus type 5 and Murine Norovirus): consult to ivami@ivami.com.
  • Basic price with only two viruses (any of the three indicated as obligates by the EN 14476 standard for general virucidal activity): consult to ivami@ivami.com.
  • Basic price with only two viruses (Adenovirus type 5 and Murine Norovirus) for Limited virucidal activity according to EN 14476 standard (Activity against Adenovirus, Norovirus , Rotavirus and enveloped viruses): consult to ivami@ivami.com.
  • Basic price with one virus (any of the three indicated as obligate by the EN 14476 for general virucidal activity): consult to ivami@ivami.com.
  • Basic price with Vaccinia virus for limited activity against enveloped viruses: consult to ivami@ivami.com.

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

  • Basic price with Adenovirus type 2: consult to ivami@ivami.com.
  • Basic price with Canine Distemper virus, family Paramyxoviridae, Genus Morbillivirus) using the surrogate measles virus (family Paramyxoviridae, Genus Morbillivirus): consult to ivami@ivami.com.
  • Basic price with Enterovirus 71: consult to ivami@ivami.com.
  • Basic price with Hepatitis A virus, HM-175 strain: consult to ivami@ivami.com.
  • Basic price with Hepatitis B virus (HBV) with the Pseudorabies virus –PRV- as surrogate of HBV: consult to ivami@ivami.com.
  • Basic Price for Hepatitis C virus (HCV) with the surrogate Bovine Viral Diarrheal virus -BVDV-: consult to ivami@ivami.com.
  • Basic price with Herpes simplex virus (HSV): consult to ivami@ivami.com.
  • Basic price with Human Coronavirus humano 229E: consult to ivami@ivami.com.
  • Basic price with Human Immunodeficiency virus –HIV-, strain RF: consult to ivami@ivami.com.
  • Basic price with Influenza A H1N1 virus (or other available strain: H1N1pdm; H3N2; H5N1): consult to ivami@ivami.com.
  • Basic price with Influenza B virus: consult to ivami@ivami.com.
  • Basic price with Measles virus: consult to ivami@ivami.com.
  • Basic price with Mumps virus: consult to ivami@ivami.com.
  • Basic Price with Papillomavirus (VPH) using the surrogate BK virus (Polyomavirus): consult to ivami@ivami.com.
  • Basic Price with Papovavirus SV40using the surrogate BK virus (Polyomavirus): consult to ivami@ivami.com.
  • Basic price with Porcine Infuenza virus (Swine Influenza virus): consult to ivami@ivami.com.
  • Basic price with Respiratory Syncytial Virus (RSV): consult to ivami@ivami.com.
  • Basic price with Rotavirus: consult to ivami@ivami.com.