# Enhancing the validity of virucidal activity testing of chemical disinfectants by establishing new reference substances according to EN 14476:2019

## TL;DR

This paper introduces new reference substances for testing the effectiveness of chemical disinfectants against viruses, replacing formaldehyde due to safety concerns.

## Contribution

The study identifies glutaraldehyde and peracetic acid as suitable replacements for formaldehyde in virucidal activity testing standards.

## Key findings

- Glutaraldehyde and peracetic acid showed suitable performance as new reference substances for virucidal testing.
- The study evaluated six test viruses for stability against the new reference substances.
- Findings will be incorporated into revised European standards for virucidal efficacy testing.

## Abstract

Reference tests are crucial for ensuring the comparability and quality assurance of test results in the field of chemical disinfectant testing. For testing virucidal activity, EN 14476:2019 specifies formaldehyde as reference substance. However, due to toxicological and technical concerns, formaldehyde needs to be replaced with new and more suitable reference substances.

In order to find the replacement, in 2023-24 an international ring trial was conducted by the European Standardization Committee TC 216 WG 1 (chemical disinfectants and antiseptics, working group human medicine) with 17 participating laboratories. The goal was to evaluate the suitability of these substances for optimization of existing standards.

The study assessed the stability of the test viruses used in the disinfection test – specifically, Modified vaccinia virus Ankara, Adenovirus type 5, Murine Norovirus S99, Minute Virus of Mice, Poliovirus type 1 strain LSc-2ab and Bovine Enterovirus type 1 – to two newly selected reference substances: glutaraldehyde and peracetic acid.

The study tested reproducibility and repeatability based on a predefined test protocol.

The results of the two tested reference substances – glutaraldehyde and peracetic acid – provide new reference substance ranges for relevant test viruses. The findings are incorporated into the revision of the European standards, ensuring the quality assurance of efficacy testing in virucidal testing.