Oct. 8, 2019

Sumba Clinical Trial Results Dissemination: Spatial Repellent (SR) in Vector-Borne Diseases

JAKARTA, October 8, 2019 - The Eijkman Institute for Molecular Biology (EIMB) Jakarta, in collaboration with the University of Notre Dame, USA, has completed clinical trials in West Sumba and Southwest Sumba, East Nusa Tenggara. This study was aimed at measuring the reduced risk of malaria infection on a Spatial Repellent (SR) basis. SR clinical trials in Indonesia were also a continuation of previous study in 2014 to prove the concept on the use of SR.

According to WHO the malaria morbidity rate in 2017 was reported around 219 million cases and 435,000 people died. Malaria is transmitted by Anopheles mosquito bites. As for Dengue Hemorrhagic Fever (DHF) cases, transmission through Aedes aegypti mosquito bites is estimated at 390 million cases per year.

WHO’s latest report stated that preliminary results from the 5-year study to investigate the effects of spatial repellent on the prevention of vector-borne diseases encouraged further studies to prove the effects of spatial repellent in reducing vector-borne diseases including malaria, zika, and dengue.

The spatial repellent study

The study began when Eijkman Institute and the University of Notre Dame, USA, collaborated with the SC Johnson company to develop spatial repellent products or mosquito repellent product. Unlike topical repellent products that are applied directly to the skin, spatial repellent is designed to release active compounds into the air to repel mosquitoes so as to interrupt human-mosquito contact. Some new spatial repellent formulas (forms) which are expected to provide longer and more environmentally friendly protection are being tested at the laboratory of Malaria and Vector Resistance Unit at Eijkman Institute.

The site principal investigator in Indonesia, Prof. Syafruddin, suggested that the results of SR clinical trials in Indonesia had the potential to significantly increase the benefits of protection, especially where traditional methods of long lasting insecticidal net (LLIN) or indoor residual spraying (IRS) might be non-protective, unavailable, impractical and/or inappropriate. Overcoming/eliminating malaria in such a situation will require innovative approaches, such as SR, that provide a high protective effect against transmission and this makes SR particularly useful.

Lack of epidemiological evidence supporting WHO recommendations has been a problem in the effort to develop spatial repellent as a product that is acceptable to the public. This was revealed by Professor Nicole Achee. Findings of this study were the first step to support WHO in making appropriate recommendations for the management of a new vector control strategy.

Prof. Nicole Achee and Dr. Neil Lobo, co-principal investigators and associate professor at the University of Notre Dame, USA, also conducted research in Iquitos, Peru. The purpose of the study was to measure risk reduction from infection of Aedes-borne viruses, such as dengue and Zika, and evaluate spatial repellent product developed and manufactured by SC Johnson.

The joint research team from Eijkman Institute and the University of Notre Dame, USA, suggested that data from clinical trial results in Indonesia designed to examine the effects of spatial repellent in reducing malaria infection showed promising results. Findings of the study in the randomized village group with malaria endemicity from zero to moderate decreased in the first malaria infection by about 28%, while the randomized village group with low to moderate endemicity decreased to around 41%.

Study results dissemination

Results from the study was disseminated to public in a seminar series conducted in two locations. First seminar was held at Eijkman Institute in 8th of October 2019 and followed by a seminar held at Sinar Tambolaka Hotel, Southwest Sumba, in 11th of October 2019.

Pictures taken from the study results dissemination during a seminar at Eijkman Institute where the regent of Southwest Sumba was sharing the frame with the study investigators and SC Johnson representatives (left). The seminar was fully packed with participants from academician, government officials, and press (right).

The investigators conducting clinical trials presented the results summary to the seminar participants. The local government of Southwest Sumba, one of the locations where the study commenced, responded the results positively. The study was fully supported by Southwest Sumba local government where the regent of Kabupaten Sumba Barat Daya, dr. Kornelius Kodi Mete attended the seminar to personally witness the study results dissemination. In his remarks, he mentioned that the study results are in line with the local target of malaria elimination in Southwest Sumba in 2030.

Pictures taken during spatial repellent study results dissemination in Southwest Sumba where the clinical trial commenced.

Findings of this study were not only encouraging in terms of public health value of SR but also provided evidence to support further investments in similar studies in vector-borne diseases, such as malaria and dengue.

The complete results of this study coincided with the publication of a report from the Vector Control Advisory Group, WHO, examining the evidence of epidemiological efficacy of a new vector control device and therefore supported the development of WHO policy recommendations for the potential use of SR as a Vector Control Strategy.