Background Ivermectin is one among several potential drugs explored for its therapeutic and preventive role in COVID-19 infection. The study was aimed to explore the association between ivermectin prophylaxis and development of COVID-19 infection among healthcare workers.
Methods A hospital-based matched case-control study was conducted among healthcare workers of AIIMS Bhubaneswar, India, from September to October 2020. Profession, gender, age and date of diagnosis were matched for 186 case-control pairs. Cases and controls were healthcare workers who tested positive and negative, respectively, for COVID-19 by RT-PCR. Exposure was defined as the intake of ivermectin and/or hydroxychloroquine and/or vitamin-C and/or other prophylaxis for COVID-19. Data collection and entry was done in Epicollect5, and analysis was performed using STATA version 13. Conditional logistic regression models were used to describe the associated factors for COVID-19 infection.
Results Ivermectin prophylaxis was taken by 77 controls and 38 cases. Two-dose ivermectin prophylaxis (0.27, 95% CI, 0.15-0.51) was associated with 73% reduction of COVID-19 infection among healthcare workers for the following one month, those who were involved in physical activity (3.06 95% CI, 1.18-7.93) for more than an hour/day were more likely to contract COVID-19 infection. Type of household, COVID duty, single-dose ivermectin prophylaxis, vitamin-C prophylaxis and hydroxychloroquine prophylaxis were not associated with COVID-19 infection.
Conclusion Two-dose ivermectin prophylaxis at a dose of 300 μg/kg with a gap of 72 hours was associated 73% reduction of COVID-19 infection among healthcare workers for the following one-month. Further research is required before its large scale use.