The intervention for Dengue Epidemiology in Malaysia (iDEM) project, is a cluster randomized controlled trial that aims to assess the effectiveness of Integrated Vector Management (IVM) on the incidence of dengue in urban Malaysia. A cluster is defined as one residential area composed of neighbouring buildings that share the same facilities such as parking lots, food court, groceries store, playground, and community halls.
The full trial protocol was published previously . In short, this IVM strategy combines (1) targeted outdoor residual spraying (TORS) with K-Othrine Polyzone, (2) deployment of In2Care Mosquito Traps as auto-dissemination devices (ADDs), and (3) active community engagement (CE) activities. The latter is carried out by community engagement officers specially trained for the purpose of the trial, each responsible for a defined number of clusters.
Community engagement activities are held in management offices and community halls during weekdays, weekends or evening. They consist of meetings with the community in the study areas to explain the purpose of the study. In parallel, volunteers are identified to inform the field health care workers about potential vandalism, and the need for replacement of ovitraps or ADDs. Communities are urged to cooperate during spraying and not interfere with ADD equipment installed in their environment. We expect these regular meetings to build public understanding and trust that would favour continued compliance of participating clusters and their collaboration with the field workers during the intervention cycles. During CE visits, banners, posters and brochures are distributed to explain the objectives of the study and the role of the community during and following the deployment of the intervention.
In total, 280 clusters located in the Federal Territory of Kuala Lumpur and Putrajaya were allocated at random to receive either the combination of proactive IVM and routine vector control activities, or only the routine vector control activities.
The trial was expected to run for two years and include six intervention cycles. TORS was planned to be conducted every four months in all clusters in intervention areas. ADDs were distributed in the ground floors, first floors, top floors and evenly among intermediate floors at the beginning of the intervention and had to be serviced every two months. ADD services consist of ensuring that there is still adequate amount of the active ingredients, adding water inside the container, and recording and then replacing the damaged ADDs. Intervention cycles were planned to be sequential over the study period (Figure 1). Community engagement events were planned as a continuous activity throughout the lifespan of the trial.
Our operational activities, including the implementation of TORS and ADDs, started on February 10, 2020, only a few weeks before the implementation of non-pharmaceutical interventions to contain the spread of COVID-19 in Malaysia. Due to the MCOs and the requirements to minimise face-to-face contacts with participants, the trial was completely stopped for a period of two weeks, from March 23 to April 5 2020, to prepare the documents required by the enforcement department (Malaysian Royal Police, Ministry of Health and Malaysia National Security Council). These documents were: a SOP for the community engagement steps during the pandemic; a SOP for operators and personnel to conduct TORS and quality control evaluations, and service the ADDs; and a SOP for personnel to collect the entomological data in the control and intervention clusters.
The pandemic forced the research and implementation team to think about how best to ensure the continuity of the trial and its procedures. The solutions had to be adaptable to different situations of the pandemic while preserving the safety of field workers, the continuity of vector control interventions and the CE activities.
Thanks to the strong support of the Institute for Medical Research (IMR), a division of the Malaysian Ministry of Health, an authorization letter was provided by the IMR director to the field operation team to declare the necessity of their work to continue the trial related vector control activities, i.e., ADD deployment and TORS.
Major challenges and solutions deployed
The first issue was the safety of field workers when conducting their work during the pandemic, and this was ensured by equipping them with complete personal protective equipment (PPE) and by following the 3Ws and 3Cs rules. A formal training session was conducted in small groups on how to use and dispose of the PPE properly. Furthermore, field workers were tested for COVID-19 as soon as symptoms appeared or high-risk contacts were detected. Also, they benefited from vaccination once it was available in the country. All field workers, 9 research assistants, and 22 supervisors and operators have completed the two doses of COVID-19 vaccine.
The second most important issue was to adapt the implementation plan for vector control activities, i.e., to maintain the scheduled turnover for 6 cycles of TORS application every four months, and ADD services every two months . Due to the pandemic and budget shortage, we had to consider the option of stopping the intervention after only 4 cycles. The trial protocol was written according to the SPIRIT statement, and no interim analysis or early stopping of the trial were anticipated. Also, publication and dissemination of the results based on only four cycles, instead of the six cycles initially planned, could have affected the power of the study and the credibility of the results. The maintenance of a two-year intervention trial was also critical in handling the high temporal variability of dengue. Thanks to operational changes adopted, we were able to maintain the original six cycles, as it is shown in the lower panel of Figure 1.
During the MCO, vector control activities were carried out with a restricted number of field workers in each cluster. The field team had to be divided into small teams, each with 6 to 8 operators, rather than the original plan with up to 18-24 operators in a given cluster. The RMCO started on June 7 2020, allowing the field operation team to continue in a larger group but still comply with the aforementioned SOPs.
From January 2021 to May 2021, Malaysia experienced an increasing wave of COVID-19 cases throughout the country. As a response to the increasing cases, the government implemented another MCO following the same rules as the MCO 1.0. In three iDEM intervention clusters with a high number of COVID-19 cases, or under the instruction for Enhanced Movement Control Order (EMCO), ADDs services and entomological data collection activities were postponed for a period of four to six weeks until clearance was obtained from the Malaysia National Security Council. The obtention of the clearance was based on the number of positive COVID‑19 cases in the area.