Efficacy dossier

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).

Tests

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:

Instrument disinfection:	Germ carrier method. The bacteria are placed on a microscope slide, which is then disinfected in a solution of the test product.
Hand disinfection:	Hygienic treatment of the hands through rubbing. Three levels/types of effectiveness are recognised: Hygienic hand disinfection (EN1500). Clean hands. Hygienic hand washing (EN1499). Dirty hands. Surgical hand disinfection (EN12791). Clean hands.
Surface disinfection:	Treatment of the surface, drying, application of the disinfectant, which can dry during application. Different tests must be used for disinfection by wiping, spraying and fogging.

Instrument disinfection:

Germ carrier method. The bacteria are placed on a microscope slide, which is then disinfected in a solution of the test product.

Hand disinfection:

Hygienic treatment of the hands through rubbing. Three levels/types of effectiveness are recognised:

Hygienic hand disinfection (EN1500). Clean hands.
Hygienic hand washing (EN1499). Dirty hands.
Surgical hand disinfection (EN12791). Clean hands.

Surface disinfection:

Treatment of the surface, drying, application of the disinfectant, which can dry during application. Different tests must be used for disinfection by wiping, spraying and fogging.

These two mandatory phases provide detailed information on the efficacy of a disinfectant. They determine:

the different target organisms,
effect concentrations,
and the contact times required for the product to have a satisfactory effect.

As these tests are standardised, they allow a reliable comparison between the compositions of the various active substances.

Efficacy assessments must be conducted according to recognised standards at competent labs (bacteriology, virology, etc.) with an appropriate quality assurance system. Full copies of the reports must be submitted to us. Test reports must contain all the information necessary to interpret the results. All test and control data must be described and specified as required by the standards. We also require that the report contain clear details of the active substances of the formula tested, including the applicable concentrations. The expert opinions must be signed by the scientist responsible. In cases of doubt the office may require the raw data and a random sample for analysis.

Subsequent changes to an expert report are not permitted. Any corrections, amendments or deletions must be made as a supplement to the report in which the changes made and the date and reasons for these changes are specified.

Details of the standard tests to be submitted for each area of application are given on the files below:

(1) Guidance on the Biocidal Products Regulation, Volume II Efficacy - Assessment and Evaluation (Parts B+C) of Efficacy (Parts B+C)