Gabaldon 1959 VEN.
| Methods | Dates of study: 1956‐1957 Location of study: Venezuela Malaria endemicity (incidence): 0.4/1000 baseline monthly incidence Transmission season: May to November Malaria species: P. vivax Vector species: A. aquasalis, A. nuneztovari Study design: Uncontrolled before‐and‐after study Evaluation design: Active and passive surveillance |
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| Participants | Age groups included: Ages > 1 month Sample size Intervention group 1 (mean): 111,995 |
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| Interventions | Intervention group 1: Eastern Venezuela (174 localities, 3084 houses, 16,416 persons) and Western Venezuela (735 localities, 17,638 houses, 95,579 persons): MDA to all persons aged > 1 month with pyrimethamine 50 mg per week for 24 weeks from July 1957 to December 1957. Coverage not specified. Co‐intervention with IRS. | |
| Outcomes | Parasitaemia incidence No adverse event surveillance conducted No adverse events reported |
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| Notes | MDA added to IRS program | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | High risk | No comparison group |
| Allocation concealment (selection bias) | High risk | No comparison group |
| Baseline imbalance (selection bias) | High risk | No comparison group |
| Contamination protection | High risk | No comparison group |
| Blinding of participants and personnel (performance bias) All outcomes | High risk | No comparison group |
| Blinding of outcome assessment (detection bias) All outcomes | High risk | No comparison group |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | All houses numbered. Envelope system for drug dispensers and slide collectors. Cooperation of the people was excellent. Active search for all infections and passive search at all medical dispensaries in the area. |
| Selective reporting (reporting bias) | Low risk | Most persons received more than 19 treatments; however, the actual figures are not reported due to "lack of mechanical tabulation of the data". The number of persons with relapses who had less than 19 treatments demonstrated similar trends to those who received 19 or more treatments. |
| Other bias | Low risk | No other bias detected |