Prophylaxis RCT in Singapore with 3,037 low risk patients, showing lower serious cases, lower symptomatic cases, and lower confirmed cases of COVID-19 with all treatments (ivermectin, HCQ, PVP-I, and Zinc + vitamin C) compared to vitamin C.
Meta-analysis of vitamin C in 6 previous trials shows a benefit of 16%, so the actual benefit of ivermectin, HCQ, and PVP-I may be higher. Cluster RCT with 40 clusters.
There were no hospitalizations and no deaths. NCT04446104
Seet et al., 4/14/2021, Cluster Randomized Controlled Trial, Singapore, Asia, peer-reviewed, 15 authors, this trial compares with another treatment - results may be better when compared to placebo.
risk of COVID-19 severe case, 49.7% lower, RR 0.50, p = 0.03, treatment 33 of 634 (5.2%), control 64 of 619 (10.3%).
risk of COVID-19 case, 26.9% lower, RR 0.73, p = 0.03, treatment 300 of 634 (47.3%), control 433 of 619 (70.0%), adjusted per study, odds ratio converted to relative risk, model 6.
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.