Of the 7,345 cases of COVID-19, 3,034 occurred in non-users, 1,627 in sporadic
users, and 289 in strict users, while the remaining cases occurred in the intermediate levels
of ivermectin use. Strict users were older (p < 0.0001) and non-significant higher
prevalence of type 2 diabetes and hypertension. COVID-19 infection rate was 39% lower
among strict users [4.03% infection rate; risk ratio (RR), 0.61; 95% confidence interval
(n = 289 in each group for both comparisons; 95%CI), 0.53 – 0.70; p < 0.0001] than in
non-users (6.64% infection rate), and non-significant 11% reduction compared to
sporadic users (4.54% infection rate) (n = 1,627 in each group; RR, 0.89; 95%CI 0.76 –
1.03; p = 0.11). Hospitalization rate was reduced by 100% in strict users, compared to
non-users and to sporadic users, both before and after PSM (RR, 0.00; 95%CI, not
applicable; p < 0.0001). After PSM, hospitalization rate was 35% lower among sporadic
users than non-users (RR, 0.65; 95%CI, 0.44 – 0.70; p = 0.03). In propensity score
matched groups, multivariate-adjusted mortality rate was 90% lower in strict users
compared to non-users (RR, 0.10, 95%CI, 0.02 – 0.45; p = 0.003) and 79% lower than in
sporadic users (RR, 0.21; RR, 0.04 – 1.00; p = 0.05), while sporadic users had a 37%
reduction in mortality rate compared to non-users (RR, 0.63; 95%CI, 0.41 – 0.99; p =
0.043). Risk of dying from COVID-19 was 86% lower among strict users than non-users
(RR, 0.14; 95%CI, 0.03 – 0.57; p = 0.006) and marginally significant, 72% lower than
sporadic users (RR, 0.28; 95%CI, 0.07 – 1.18; p = 0.083), while sporadic users had a 51%
reduction compared to non-users (RR, 0.49; 95%CI, 0.32 – 0.76; p = 0.001).