Context: SARS-CoV-2 is a global public-health concern. Interventions to prevent infection are urgently needed. The anti-inflammatory and antiviral effects of neem make it a potential agent for COVID-19 prophylaxis.
Objective: The study intended to evaluate the prophylactic effects of neem capsules for persons at high risk of COVID-19 infection due to contact with COVID-19 positive patients.
Design: The research team designed a prospective, randomized, double-blind, placebo-controlled, parallel-design study.
Setting: The study was conducted at a single center in India.
Participants: Participants were 190 healthcare workers at the hospital or relatives of patients with COVID-19 infection.
Intervention: Of the 190 participants, 95 were in the intervention group and 95 in the control group. Participants received 50 mg of a proprietary, patent-pending, neem-leaf extract or a placebo orally in capsules, twice a day for 28 days.
Outcome measures: The number of individuals positive for COVID-19 between baseline and follow-up on day 56 was the primary outcome measure. Secondary measures included an evaluation of neem's safety and its effects on quality of life (QOL) and changes in biomarkers.
Results: The mean age of participants was 36.97 years, and 68.42% were male. Total 13 subjects tested positive during the study. All were asymptomatic. Of the 154 participants who completed the study per-protocol, 11 tested positive, 3 in the intervention group and 8 in the control group. The probability of COVID-19 infection in participants receiving the intervention was 0.45 times that of participants receiving the placebo, a relative risk of 0.45, with the effectiveness of the intervention being around 55%. Treatment-emergent adverse events (TEAEs) in both groups were minimal and were of grade 1 or 2 in severity. Biomarkers and QOL remained stable in both groups.
Conclusions: The study found a reduced risk of COVID-19 infection in participants receiving neem capsules, which demonstrates its potential as a prophylactic treatment for the prevention of COVID-19 infection. The findings warrant further investigation in clinical trials.