Efficacy assessments in efficacy dossiers
Microorganisms multiply at a very high rate but are not visible to the naked eye. Because users can’t check the efficacy of a product by eye, they have to rely on the products they use being reputable.
Disinfectants only provide effective protection from infection if they substantially reduce the number of germs. It is up to applicants to demonstrate the efficacy of products they intend to market. The range of effects and limits to efficacy must be specified in the product documentation (label, directions and advertising).
There have been standardised tests in various countries for more than 30 years. To normalise test methods and the evaluations conducted by examination authorities, the European Committee for Standardization (CEN) has created a technical committee for disinfectants. Standard EN 14885, Chemical disinfectants and antiseptics – application of European Standards for chemical disinfectants and antiseptics, provides an overview of the available tests and the areas for which they ae designed. It also contains overview tables with tests for the different application methods. The EU’s document on the efficacy of disinfectants (1) likewise serves as a basis for determining what tests are used.
The test section consists of three levels. Each phase and level produces differentiated results on the basis of which the strengths and weaknesses of a product can be determined.
- Phase 1 consists of a suspension test. This phase will not be accepted for the dossier as it does not produce sufficiently meaningful results.
- Level 1 of Phase 2 consists of a quantitative suspension test. In addition to being diluted with water, the product is diluted with a solution of impurities to simulate organic contamination. This type of contamination is frequently encountered in practice because surfaces, instruments and hands may be dirty. This phase is important, because certain active substances react with proteins, which inhibits them and cause the product to lose its effect. This test is quantitative because it is used to determine the number of eliminated target organisms expressed as a log10 reduction factor.
- Level 2 of Phase 2 is also crucial, as the conditions of the test are comparable with the real-life conditions when a product is used in practice. In other words, these tests are designed to simulate real-life conditions. Unlike the tests in the two previous levels, which are the same for all types of application, the tests in this final phase vary according to what the disinfectant is used for. In Level 2 of Phase 2 the following tests must be conducted depending on what the disinfectant is used for: