Trial Outcomes & Findings for Quantifying the Epidemiological Impact of Targeted Indoor Residual Spraying on Aedes-borne Diseases (NCT NCT04343521)
NCT ID: NCT04343521
Last Updated: 2025-09-18
Results Overview
The number of symptomatic children with laboratory confirmed, by reverse transcription-polymerase chain reaction (RT-PCR) or immunoglobulin M/ immunoglobulin G (IgM/IgG) enzyme-linked immunosorbent assay (ELISA), Aedes-borne Viruses infections. The number of any Aedes-borne virus infection during three seasons of high transmission is described, as well as the number of Dengue virus (DENV), Chikungunya virus (CHIKV), Zika virus (ZIKV) and coinfections.
COMPLETED
NA
4461 participants
18 months of active surveillance during high transmission seasons (each 6 months in duration) during 3 years (July through December in 2021, 2022, and 2023)
2025-09-18
Participant Flow
Participants are children from households in the study clusters in Merida, Yucatan, Mexico. Participant enrollment began November 3, 2020 and all follow-up assessments were completed by April 28, 2024.
Unit of analysis: Households
Participant milestones
| Measure |
Targeted Indoor Residual Spraying (TIRS)
Children residing in households located in Targeted Indoor Residual Spraying (TIRS) clusters that were offered the intervention.
During Targeted Indoor Residual Spraying (TIRS), spraying of the insecticide Actellic 300CS began in May or June extending for 1 to 2 months. Residents were asked to temporarily leave the house during treatment and wait half an hour to one hour for the product to dry before re-entering the house. Insecticide application followed a strict protocol developed by the Centers for Disease Control and Prevention (CDC), Emory University, and the Universidad Autónoma de Yucatán.
|
Routine Aedes-borne Virus (ABV) Prevention and Control
Children residing in households located in routine Aedes-borne virus (ABV) prevention and control clusters, without Targeted Indoor Residual Spraying (TIRS).
|
|---|---|---|
|
Overall Study
STARTED
|
2239 13487
|
2222 13486
|
|
Overall Study
COMPLETED
|
1835 10472
|
1718 13486
|
|
Overall Study
NOT COMPLETED
|
404 3015
|
504 0
|
Reasons for withdrawal
| Measure |
Targeted Indoor Residual Spraying (TIRS)
Children residing in households located in Targeted Indoor Residual Spraying (TIRS) clusters that were offered the intervention.
During Targeted Indoor Residual Spraying (TIRS), spraying of the insecticide Actellic 300CS began in May or June extending for 1 to 2 months. Residents were asked to temporarily leave the house during treatment and wait half an hour to one hour for the product to dry before re-entering the house. Insecticide application followed a strict protocol developed by the Centers for Disease Control and Prevention (CDC), Emory University, and the Universidad Autónoma de Yucatán.
|
Routine Aedes-borne Virus (ABV) Prevention and Control
Children residing in households located in routine Aedes-borne virus (ABV) prevention and control clusters, without Targeted Indoor Residual Spraying (TIRS).
|
|---|---|---|
|
Overall Study
Adverse Event
|
0
|
2
|
|
Overall Study
Death
|
1
|
2
|
|
Overall Study
Lost to follow-up due to moving from the cluster
|
327
|
393
|
|
Overall Study
Withdrawal by Subject
|
70
|
95
|
|
Overall Study
Withdrawal by study team
|
6
|
12
|
Baseline Characteristics
Quantifying the Epidemiological Impact of Targeted Indoor Residual Spraying on Aedes-borne Diseases
Baseline characteristics by cohort
| Measure |
Targeted Indoor Residual Spraying (TIRS)
n=2239 Participants
Children residing in households located in Targeted Indoor Residual Spraying (TIRS) clusters that were offered the intervention.
|
Routine Aedes-borne Virus (ABV) Prevention and Control
n=2222 Participants
Children residing in households located in routine Aedes-borne virus (ABV) prevention and control clusters, without Targeted Indoor Residual Spraying (TIRS).
|
Total
n=4461 Participants
Total of all reporting groups
|
|---|---|---|---|
|
Age, Categorical
<=18 years
|
2239 Participants
n=99 Participants
|
2222 Participants
n=107 Participants
|
4461 Participants
n=206 Participants
|
|
Age, Categorical
Between 18 and 65 years
|
0 Participants
n=99 Participants
|
0 Participants
n=107 Participants
|
0 Participants
n=206 Participants
|
|
Age, Categorical
>=65 years
|
0 Participants
n=99 Participants
|
0 Participants
n=107 Participants
|
0 Participants
n=206 Participants
|
|
Sex: Female, Male
Female
|
1108 Participants
n=99 Participants
|
1053 Participants
n=107 Participants
|
2161 Participants
n=206 Participants
|
|
Sex: Female, Male
Male
|
1131 Participants
n=99 Participants
|
1169 Participants
n=107 Participants
|
2300 Participants
n=206 Participants
|
|
Ethnicity (NIH/OMB)
Hispanic or Latino
|
2239 Participants
n=99 Participants
|
2222 Participants
n=107 Participants
|
4461 Participants
n=206 Participants
|
|
Ethnicity (NIH/OMB)
Not Hispanic or Latino
|
0 Participants
n=99 Participants
|
0 Participants
n=107 Participants
|
0 Participants
n=206 Participants
|
|
Ethnicity (NIH/OMB)
Unknown or Not Reported
|
0 Participants
n=99 Participants
|
0 Participants
n=107 Participants
|
0 Participants
n=206 Participants
|
|
Region of Enrollment
Mexico
|
2239 Participants
n=99 Participants
|
2222 Participants
n=107 Participants
|
4461 Participants
n=206 Participants
|
PRIMARY outcome
Timeframe: 18 months of active surveillance during high transmission seasons (each 6 months in duration) during 3 years (July through December in 2021, 2022, and 2023)Population: This analysis includes symptomatic children who were tested for Andes-borne viruses during high transmission seasons.
The number of symptomatic children with laboratory confirmed, by reverse transcription-polymerase chain reaction (RT-PCR) or immunoglobulin M/ immunoglobulin G (IgM/IgG) enzyme-linked immunosorbent assay (ELISA), Aedes-borne Viruses infections. The number of any Aedes-borne virus infection during three seasons of high transmission is described, as well as the number of Dengue virus (DENV), Chikungunya virus (CHIKV), Zika virus (ZIKV) and coinfections.
Outcome measures
| Measure |
Targeted Indoor Residual Spraying (TIRS)
n=402 Participants
Children residing in households located in Targeted Indoor Residual Spraying (TIRS) clusters that were offered the intervention.
|
Routine Aedes-borne Virus (ABV) Prevention and Control
n=423 Participants
Children residing in households located in routine Aedes-borne virus (ABV) prevention and control clusters, without Targeted Indoor Residual Spraying (TIRS).
|
|---|---|---|
|
Number of Symptomatic Participants Testing Positive for Aedes-borne Virus Infections That Are Laboratory Confirmed or Serologically
Number of Children Testing Positive for All Aedes-borne Viruses
|
213 Participants
|
209 Participants
|
|
Number of Symptomatic Participants Testing Positive for Aedes-borne Virus Infections That Are Laboratory Confirmed or Serologically
Number of Children Testing Positive for DENV
|
151 Participants
|
146 Participants
|
|
Number of Symptomatic Participants Testing Positive for Aedes-borne Virus Infections That Are Laboratory Confirmed or Serologically
Number of Children Testing Positive for CHIKV
|
1 Participants
|
0 Participants
|
|
Number of Symptomatic Participants Testing Positive for Aedes-borne Virus Infections That Are Laboratory Confirmed or Serologically
Number of Children Testing Positive for ZIKV
|
39 Participants
|
55 Participants
|
|
Number of Symptomatic Participants Testing Positive for Aedes-borne Virus Infections That Are Laboratory Confirmed or Serologically
Number of Children Testing Positive for Coinfection
|
22 Participants
|
8 Participants
|
SECONDARY outcome
Timeframe: Up to 36 months, during serosurvey seasons 2021-2022, 2022-2023, and 2023-2024Population: The population analyzed includes children living in study households where annual surveillance sampling for Aedes-borne viruses occurred.
Number of laboratory confirmed (IgG ELISA and neutralization testing) Aedes-borne Viruses (DENV, CHIKV and ZIKV) in annual surveillance samples.
Outcome measures
| Measure |
Targeted Indoor Residual Spraying (TIRS)
n=1933 Number of Tests
Children residing in households located in Targeted Indoor Residual Spraying (TIRS) clusters that were offered the intervention.
|
Routine Aedes-borne Virus (ABV) Prevention and Control
n=1932 Number of Tests
Children residing in households located in routine Aedes-borne virus (ABV) prevention and control clusters, without Targeted Indoor Residual Spraying (TIRS).
|
|---|---|---|
|
Number Positive Tests of Laboratory Confirmed Aedes-borne Viruses Infections By Season
Number of Positive Tests for all Aedes-borne Viruses During 2021-2022 Season
|
36 Number of Tests
|
39 Number of Tests
|
|
Number Positive Tests of Laboratory Confirmed Aedes-borne Viruses Infections By Season
Number of Positive Tests for all Aedes-borne Viruses During 2022-2023 Season
|
216 Number of Tests
|
166 Number of Tests
|
|
Number Positive Tests of Laboratory Confirmed Aedes-borne Viruses Infections By Season
Number of Positive Tests for all Aedes-borne Viruses During 2023-2024 Season
|
169 Number of Tests
|
204 Number of Tests
|
SECONDARY outcome
Timeframe: Up to 6 months (mosquito pools were collected during the 6 months post TIRS spraying samplings in 2021)Population: This analysis includes households where mosquito sampling occurred. Individual participants were not analyzed. Only households contributed data.
Ae. aegypti mosquito infection rate with Aedes-borne Viruses (DENV, CHIKV and ZIKV) assessed by the number of positive RT-PCR tests. Infection is mosquitoes is analyzed by collecting binary data (a mosquito pool is either infected or not) and transforming that into minimum infection rates (MIR) with the calculation: (1/number of mosquitoes in the pool) times 1000. Households were randomly selected for testing; houses were eligible for testing if they were located within the central blocks and had at least one child enrolled in the study.
Outcome measures
| Measure |
Targeted Indoor Residual Spraying (TIRS)
n=160 Households samples
Children residing in households located in Targeted Indoor Residual Spraying (TIRS) clusters that were offered the intervention.
|
Routine Aedes-borne Virus (ABV) Prevention and Control
n=160 Households samples
Children residing in households located in routine Aedes-borne virus (ABV) prevention and control clusters, without Targeted Indoor Residual Spraying (TIRS).
|
|---|---|---|
|
Ae. Aegypti Mosquito Infection Rate With Aedes-borne Viruses (DENV, CHIKV and ZIKV)
|
0 Households samples
|
0 Households samples
|
SECONDARY outcome
Timeframe: Up to 36 months starting at the first TIRS applicationThe Ae. aegypti indoor entomological index of adult mosquito presence/abundance is calculated as the number of adult mosquitoes per house. Higher values mean that more mosquitoes are found within houses.
Outcome measures
| Measure |
Targeted Indoor Residual Spraying (TIRS)
n=13487 Households
Children residing in households located in Targeted Indoor Residual Spraying (TIRS) clusters that were offered the intervention.
|
Routine Aedes-borne Virus (ABV) Prevention and Control
n=13486 Households
Children residing in households located in routine Aedes-borne virus (ABV) prevention and control clusters, without Targeted Indoor Residual Spraying (TIRS).
|
|---|---|---|
|
Ae. Aegypti Indoor Entomological Index of Adult Mosquito Abundance
|
0.61 mosquitoes/house
Standard Deviation 1.1
|
1.39 mosquitoes/house
Standard Deviation 2.1
|
SECONDARY outcome
Timeframe: Up to 36 months starting at first TIRS applicationThe Ae. aegypti indoor entomological index of female mosquito presence/abundance is calculated as the number of female mosquitoes per house. Higher values mean that more mosquitoes are found within houses.
Outcome measures
| Measure |
Targeted Indoor Residual Spraying (TIRS)
n=13487 Households
Children residing in households located in Targeted Indoor Residual Spraying (TIRS) clusters that were offered the intervention.
|
Routine Aedes-borne Virus (ABV) Prevention and Control
n=13486 Households
Children residing in households located in routine Aedes-borne virus (ABV) prevention and control clusters, without Targeted Indoor Residual Spraying (TIRS).
|
|---|---|---|
|
Ae. Aegypti Indoor Entomological Index of Female Mosquito Abundance
|
0.29 mosquitoes/house
Standard Deviation 0.9
|
0.65 mosquitoes/house
Standard Deviation 1.9
|
SECONDARY outcome
Timeframe: Up to 36 months starting at first TIRS applicationThe Ae. aegypti indoor entomological index of bloodfed female mosquito presence/abundance is calculated as the number of bloodfed female mosquitoes per house. Higher values mean that more mosquitoes are found within houses.
Outcome measures
| Measure |
Targeted Indoor Residual Spraying (TIRS)
n=13487 Households
Children residing in households located in Targeted Indoor Residual Spraying (TIRS) clusters that were offered the intervention.
|
Routine Aedes-borne Virus (ABV) Prevention and Control
n=13486 Households
Children residing in households located in routine Aedes-borne virus (ABV) prevention and control clusters, without Targeted Indoor Residual Spraying (TIRS).
|
|---|---|---|
|
Ae. Aegypti Indoor Entomological Index of Bloodfed Female Mosquito Abundance
|
0.25 mosquitoes/house
Standard Deviation 0.92
|
0.53 mosquitoes/house
Standard Deviation 0.94
|
SECONDARY outcome
Timeframe: Post-intervention (up to 41 months and 26 days after the start of the intervention)Population: This analysis includes households in TIRS clusters where the head of the household completed the household survey.
Acceptability of the intervention is determined through household surveys, for households that received the intervention. Acceptability is assessed as the number of households where the head of that household would recommend the intervention to others.
Outcome measures
| Measure |
Targeted Indoor Residual Spraying (TIRS)
n=2250 Households
Children residing in households located in Targeted Indoor Residual Spraying (TIRS) clusters that were offered the intervention.
|
Routine Aedes-borne Virus (ABV) Prevention and Control
Children residing in households located in routine Aedes-borne virus (ABV) prevention and control clusters, without Targeted Indoor Residual Spraying (TIRS).
|
|---|---|---|
|
Number of Households Where the Head of Household Would Recommend the Intervention
|
2160 Households
|
—
|
SECONDARY outcome
Timeframe: Post-intervention (up to 41 months and 26 days after the start of the intervention)Population: This analysis includes households in TIRS clusters where the head of the household completed the household survey.
Safety of the intervention is assessed as the number of households receiving the TIRS intervention that had evidence of a household resident having a reaction possibly related to the insecticide, which was assessed and confirmed by study doctors.
Outcome measures
| Measure |
Targeted Indoor Residual Spraying (TIRS)
n=2250 Households
Children residing in households located in Targeted Indoor Residual Spraying (TIRS) clusters that were offered the intervention.
|
Routine Aedes-borne Virus (ABV) Prevention and Control
Children residing in households located in routine Aedes-borne virus (ABV) prevention and control clusters, without Targeted Indoor Residual Spraying (TIRS).
|
|---|---|---|
|
Number of Households With a Resident That Had a Reaction to the Insecticide
|
2 Households
|
—
|
Adverse Events
Targeted Indoor Residual Spraying (TIRS)
Routine Aedes-borne Virus (ABV) Prevention and Control
Serious adverse events
| Measure |
Targeted Indoor Residual Spraying (TIRS)
n=2239 participants at risk
Children residing in households located in Targeted Indoor Residual Spraying (TIRS) clusters that were offered the intervention.
|
Routine Aedes-borne Virus (ABV) Prevention and Control
n=2222 participants at risk
Children residing in households located in routine Aedes-borne virus (ABV) prevention and control clusters, without Targeted Indoor Residual Spraying (TIRS).
|
|---|---|---|
|
Neoplasms benign, malignant and unspecified (incl cysts and polyps)
Leukemia
|
0.00%
0/2239 • Information on adverse events was collected beginning at the time when individuals gave consent to participate in the study and continued through the final assessment (up to 41 months and 26 days).
|
0.05%
1/2222 • Information on adverse events was collected beginning at the time when individuals gave consent to participate in the study and continued through the final assessment (up to 41 months and 26 days).
|
|
Blood and lymphatic system disorders
Aplastic anemia secondary to parvovirus and rickettsiosis infection
|
0.00%
0/2239 • Information on adverse events was collected beginning at the time when individuals gave consent to participate in the study and continued through the final assessment (up to 41 months and 26 days).
|
0.05%
1/2222 • Information on adverse events was collected beginning at the time when individuals gave consent to participate in the study and continued through the final assessment (up to 41 months and 26 days).
|
Other adverse events
| Measure |
Targeted Indoor Residual Spraying (TIRS)
n=2239 participants at risk
Children residing in households located in Targeted Indoor Residual Spraying (TIRS) clusters that were offered the intervention.
|
Routine Aedes-borne Virus (ABV) Prevention and Control
n=2222 participants at risk
Children residing in households located in routine Aedes-borne virus (ABV) prevention and control clusters, without Targeted Indoor Residual Spraying (TIRS).
|
|---|---|---|
|
Infections and infestations
Admission to emergency room due to dengue with warning signs
|
0.13%
3/2239 • Information on adverse events was collected beginning at the time when individuals gave consent to participate in the study and continued through the final assessment (up to 41 months and 26 days).
|
0.09%
2/2222 • Information on adverse events was collected beginning at the time when individuals gave consent to participate in the study and continued through the final assessment (up to 41 months and 26 days).
|
|
Infections and infestations
Admission to emergency room due to suspected dengue with warning signs
|
0.04%
1/2239 • Information on adverse events was collected beginning at the time when individuals gave consent to participate in the study and continued through the final assessment (up to 41 months and 26 days).
|
0.09%
2/2222 • Information on adverse events was collected beginning at the time when individuals gave consent to participate in the study and continued through the final assessment (up to 41 months and 26 days).
|
|
General disorders
Mild allergic reaction
|
0.04%
1/2239 • Information on adverse events was collected beginning at the time when individuals gave consent to participate in the study and continued through the final assessment (up to 41 months and 26 days).
|
0.00%
0/2222 • Information on adverse events was collected beginning at the time when individuals gave consent to participate in the study and continued through the final assessment (up to 41 months and 26 days).
|
|
Gastrointestinal disorders
Gastroenteritis
|
0.04%
1/2239 • Information on adverse events was collected beginning at the time when individuals gave consent to participate in the study and continued through the final assessment (up to 41 months and 26 days).
|
0.00%
0/2222 • Information on adverse events was collected beginning at the time when individuals gave consent to participate in the study and continued through the final assessment (up to 41 months and 26 days).
|
Additional Information
Results disclosure agreements
- Principal investigator is a sponsor employee
- Publication restrictions are in place