Propensity matched retrospective prophylaxis study of healthcare workers in the Dominican Republic showing significantly lower cases with treatment, and no hospitalization with treatment (versus 2 in the PSM matched control group). The cases with treatment were mostly in the first week, with only one case in the second and third weeks, and none in the fourth week. NCT04832945.
Morgenstern et al., 4/16/2021, retrospective, propensity score matching, Dominican Republic, Caribbean, preprint, 16 authors, dosage 200μg/kg weekly.
risk of hospitalization, 80.0% lower, RR 0.20, p = 0.50, treatment 0 of 271 (0.0%), control 2 of 271 (0.7%), continuity correction due to zero event (with reciprocal of the contrasting arm), PSM.
risk of COVID-19 case, 74.0% lower, RR 0.26, p = 0.008, treatment 5 of 271 (1.8%), control 18 of 271 (6.6%), adjusted per study, PSM, multivariate Cox regression.
Effect extraction follows pre-specified rules
prioritizing more serious outcomes. For an individual study the most serious
outcome may have a smaller number of events and lower statistical signficance,
however this provides the strongest evidence for the most serious outcomes
when combining the results of many trials.