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Completed

NCT Number: NCT02556242

Targeted Indoor Residual Spraying Against Malaria

Since 2000, annual numbers of malaria cases in South Africa have sharply declined to about 5,000, with case numbers fairly stable since 2007. The principal malaria prevention strategy has consisted of generalised Indoor Residual Spraying (IRS) of all houses in malaria endemic districts. As recent case data indicate that the levels of transmission in many districts have been reduced to very low levels, the continuation of untargeted IRS in areas where there is little or no evidence of recent transmission may be unwarranted. Efforts to eliminate malaria will only be sustainable if mass prevention efforts can be scaled down in an evidence-based manner, whilst maintaining or enhancing high sensitivity of the surveillance system of the disease. This trial will provide scientific evidence for targeted malaria prevention responding to localised transmission in pre-elimination settings, compared to continuation of generalised IRS of all houses.

Two methods of IRS delivery for community malaria prevention will be compared through an open-label cluster-randomised trial consisting of two study arms with 30 clusters per arm of approximately 8,000 inhabitants per cluster.

Comparison is on the basis of non-inferiority by showing that malaria incidence in the targeted IRS arm is no higher than malaria incidence in the generalised IRS arm within a specified margin of difference, and on the basis of superiority showing that the proportion of houses targeted for spraying is higher in the intervention than the reference arm. Neighbourhood investigation in response to each locally acquired case in the intervention arm, and comparison neighbourhoods in the reference arm, will include testing for antibody sero-conversion to malarial antigens to assess whether cases arise in communities with long term exposure to malaria parasites.

The trial will be carried out in the South African provinces of Limpopo and Mpumalanga, in localities which have average reported incidence of malaria of <5 cases per 1000 per annum over the past five years.

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Key information

Conditions

Malaria Infections Mosquito-Borne Diseases Parasitic Diseases Protozoan Infections Vector Borne Diseases

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 4

Primary location

Provincial Malaria Control Programme, Tzaneen, Limpopo, South Africa

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About this study

Two methods of IRS delivery for malaria prevention, targeted spraying versus annual generalised spraying, will be compared through an open-label cluster randomised trial consisting of two trial arms with 30 clusters per arm. Clusters will be artificial constructs made up of groups of spray localities or complete wards to comprise populations of about 5,000 to 10,000 persons. The unit of randomisation will be the cluster.

The intervention arm of the trial will receive IRS delivery through targeted reactive spraying in the neighbourhood of recent local cases only; the reference (control) arm of the trial will receive IRS through generalised annual spraying of all structures as per standard current practice.

Comparison will be on the basis of non-inferiority by showing that malaria incidence in the targeted IRS arm is no higher than malaria incidence in the generalised IRS arm within a specified margin of difference, and on the basis of superiority showing that the proportion of houses sprayed, of those targeted for spraying, is higher in the intervention than the reference arm. Neighbourhood investigation in response to each locally acquired case in the intervention arm, and comparison neighbourhoods in the reference arm will include testing for antibody sero-conversion to malarial antigens to assess whether cases arise in communities with long term exposure to malarial parasites.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Entire communities of approximately 8000 persons
  • Residents in malaria endemic districts of Limpopo and Mpumalanga Province
  • Areas with local malaria incidence <5 cases per 1000 per year on average over 5 years

Treatment and study plan

Targeted indoor residual spraying

Other

IRS is carried out in neighbourhoods of cases

Generalised Indoor residual spraying

Other

IRS is carried out as normally practiced

Primary outcomes

  1. Malaria incidence, by routine passive case detection, of clinical malaria (fever ≥37.5°C, or history of fever (48 hours), in the presence of parasitaemia confirmed by RDT or microscopy).

    Time frame: Communities will be followed for up to 20 months

Secondary outcomes

  1. Intervention costs per 1,000 households and cost-effectiveness of reactive, targeted indoor residual spraying (TIRS) compared to generalised IRS (GIRS)

    Time frame: Up to 20 months

    Cost of spray operations will be determined in each study arm

  2. Proportion of structures targeted for IRS unsprayed

    Time frame: Up to 20 months whenever reactive spraying is triggered

  3. Household compliance (not painting, washing, re-plastering )

    Time frame: By cross sectional household survey after 18 months

    In a representative sample household survey in all clusters, a questionnaire will be used in which householders will be asked whether they painted, re-plastered or washed walls after spraying

  4. Householder acceptability of IRS

    Time frame: By cross sectional household survey after 18 months

    In a representative sample household survey in all clusters, a questionnaire will be used in which householders will be asked whether they want their house sprayed with insecticide in future

  5. If unsprayed, proportions due to refusals, spray teams not making contact and spray teams not calling back

    Time frame: By cross sectional household survey after 18 months

    In a representative sample household survey in all clusters, a questionnaire will be used in which householders whose houses remained unsprayed will be asked whether this was because they refused or because spray teams did not make contact or did not call back if they were away

  6. Sero-prevalence of antibodies to malaria antigens AMA-1 and MSP-1-19

    Time frame: By cross sectional household survey after 18 months

    In a representative sample household survey in all clusters, a filter paper dried blood spot a will be taken from a sample of individuals of all ages, subject to informed written consent

Sponsors and collaborators

Lead sponsor

London School of Hygiene and Tropical Medicine

Other

Collaborators

  • Medical Research Council
  • National Department of Health, South Africa
  • National Institute for Communicable Diseases, South Africa
  • University of Witwatersrand, South Africa

Registry information

Official study title

From Malaria Control to Sustainable Elimination: Cluster Randomised Trial Comparing Targeted Versus Generalised Vector Control in South Africa

Acronym: TIRS

Important dates

Study start
2015
Primary completion
2017
Study completion
2017
First posted
Sep 22, 2015
Registry last updated
Jul 23, 2020

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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