Healthcare workers (HCWs) are vulnerable to getting infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Preventing HCWs from getting infected is a priority to maintain healthcare services. The therapeutic and preventive role of ivermectin in coronavirus disease 2019 (COVID-19) is being investigated. Based on promising results of in vitro studies of oral ivermectin, this study was conducted with the aim to demonstrate the prophylactic role of oral ivermectin in preventing SARS-CoV-2 infection among HCWs at the All India Institute of Medical Sciences (AIIMS) Bhubaneswar.
A prospective cohort study was conducted at AIIMS Bhubaneswar, which has been providing both COVID and non-COVID care since March 2020. All employees and students of the institute who provided written informed consent participated in the study. The uptake of two doses of oral ivermectin (300 μg/kg/dose at a gap of 72 hours) was considered as exposure. The primary outcome of the study was COVID-19 infection in the following month of ivermectin consumption, diagnosed as per Government of India testing criteria (real-time reverse transcriptase polymerase chain reaction [RT-PCR]) guidelines. The log-binomial model was used to estimate adjusted relative risk (ARR), and the Kaplan-Meier failure plot was used to estimate the probability of COVID-19 infection with follow-up time.
Of 3892 employees, 3532 (90.8%) participated in the study. The ivermectin uptake was 62.5% and 5.3% for two doses and single dose, respectively. Participants who took ivermectin prophylaxis had a lower risk of getting symptoms suggestive of SARS-CoV-2 infection (6% vs 15%). HCWs who had taken two doses of oral ivermectin had a significantly lower risk of contracting COVID-19 infection during the following month (ARR 0.17; 95% CI, 0.12-0.23). Females had a lower risk of contracting COVID-19 than males (ARR 0.70; 95% CI, 0.52-0.93). The absolute risk reduction of SARS-CoV-2 infection was 9.7%. Only 1.8% of the participants reported adverse events, which were mild and self-limiting.
Two doses of oral ivermectin (300 μg/kg/dose given 72 hours apart) as chemoprophylaxis among HCWs reduced the risk of COVID-19 infection by 83% in the following month. Safe, effective, and low-cost chemoprophylaxis has relevance in the containment of pandemic alongside vaccine.