Public health pesticide registration process

The general registration process described in this Toolkit is applicable both to public health pesticides and to agricultural pesticides. There are no fundamental differences in the steps that should be followed from the initial application for a registration of a public health pesticide to the final registration decision. View the Registration Process Module for more information about these registration steps.

Evaluation procedures for public health pesticides

Public health pesticides may have very different use patterns from agricultural pesticides. They can be used indoors or outdoors close to habitations, while agricultural pesticides are often used in crop fields. Public health pesticides may need to be applied intentionally to ponds and streams for disease vector control, while this is rarely the case in agriculture. Furthermore, public health pesticide formulations and their application methods can be very specific, such as insecticide treated nets, application of residual spraying on house walls, aerosols, mosquito coils or rodenticide baits. As a result, the evaluation of efficacy and of risks of public health pesticides tends to be different from agricultural pesticides. On the other hand, the evaluation of product chemistry will be very similar.

The WHO Vector Ecology and Management Unit provides different types of guidance for efficacy testing and risk assessment.

Efficacy testing of public health pesticides

Unlike for agricultural pesticides, the procedures for evaluating the efficacy of many types of public health pesticides have been established globally. In WHO, it is done through the WHO Prequalification programme and focuses on pesticides used in vector control.

In addition to publishing efficacy testing protocols, WHO evaluates individual public health pesticides for various uses, in particular those used in mosquito control. Efficacy evaluation is done based on a global data set of studies, conducted with the same protocols and adhering to the same quality control. The WHO Prequalification Team (PQT) evaluates these studies and makes recommendations on insecticides and dose rates that have been found to be effective against public health pests.

The WHO efficacy evaluation process is further explained here.

Risk assessment of public health pesticides

Human health and environmental risks of public health pesticides may be quite different from agricultural pesticides. Public health pesticides are often used indoor (e.g. mosquito coils, cockroach pastes, indoor residual spraying, insecticide treated bed nets) or close to habitations (e.g. space spraying against mosquitos, larviciding in water reservoirs in towns). Human exposure to the pesticide may be unavoidable and in some cases follows pathways not encountered in agriculture.

Environmental risks of public health pesticides are in many cases lower than in agriculture (e.g. for indoor pesticide use, insecticide treated bed nets), but in some instances environmental exposure may be considerable (e.g. aerial mosquito control, larviciding in natural ponds, blackfly control in rivers or streams).

Specific human health and environmental risk assessment procedures for public health pesticides have been developed by WHO. These at present refer to mosquito control, and are further explained here. Additional risk assessment methods are available from other regulators.

Appropriate efficacy and risk assessment methods of public health pesticides can be accessed through the Assessment Methods module of the Toolkit.

Inclusion of WHO evaluations in the national/regional registration process

WHO evaluates vector control pesticides, using data on efficacy and risks submitted by applicants (generally pesticide companies). When a vector control product has been assessed by WHO and found to be acceptable for its intended use, it is included in the so-called “prequalified list”. This prequalification procedure is explained elsewhere.

Pesticide registration authorities can make use of these international evaluations in various ways, for instance:

1. If a vector control product has been listed by WHO on its Prequalified List, no additional local efficacy trials or risk assessment is required. This is justified by the fact that to be listed by WHO, the product has been tested under a range of conditions, in different countries, and found to show robust efficacy. Its risks have also been evaluated using generic models and found to be acceptable under realistic worst case conditions.
    
2. If a vector control product has been listed by WHO on its Prequalified List, only limited additional local data or assessments are required. This may be one or more local efficacy trials, since it is expected that conditions of use in the local situation will be considerably different from the conditions tested under the WHO scheme. Or more locally specific risk assessments are required, to cover specific use situations in the country.
    
3. If a vector control product has not (yet) been listed by WHO, a full data package needs to be submitted by the applicant and a locally relevant efficacy and risk assessment will be conducted by the registration authority.

Pesticide registration authorities can thus optimize their – often limited – human resources by making use of evaluations conducted by WHO. This will generally also reduce the costs for applicants.