Positive impact of oral hydroxychloroquine and povidone-iodine throat spray for COVID-19 prophylaxis: An open-label randomized trial

Int J Infect Dis. 2021 May:106:314-322. doi: 10.1016/j.ijid.2021.04.035. Epub 2021 Apr 20.

Abstract

Background: We examined whether existing licensed pharmacotherapies could reduce the spread of coronavirus disease 2019 (COVID-19).

Methods: An open-label parallel randomized controlled trial was performed among healthy migrant workers quarantined in a large multi-storey dormitory in Singapore. Forty clusters (each defined as individual floors of the dormitory) were randomly assigned to receive a 42-day prophylaxis regimen of either oral hydroxychloroquine (400 mg once, followed by 200 mg/day), oral ivermectin (12 mg once), povidone-iodine throat spray (3 times/day, 270 μg/day), oral zinc (80 mg/day)/vitamin C (500 mg/day) combination, or oral vitamin C, 500 mg/day. The primary outcome was laboratory evidence of SARS-CoV-2 infection as shown by either: (1) a positive serologic test for SARS-CoV-2 antibody on day 42, or (2) a positive PCR test for SARS-CoV-2 at any time between baseline and day 42.

Results: A total of 3037 asymptomatic participants (mean age, 33.0 years; all men) who were seronegative to SARS-CoV-2 at baseline were included in the primary analysis. Follow-up was nearly complete (99.6%). Compared with vitamin C, significant absolute risk reductions (%, 98.75% confidence interval) were observed for oral hydroxychloroquine (21%, 2-42%) and povidone-iodine throat spray (24%, 7-39%). No statistically significant differences were observed with oral zinc/vitamin C combination (23%, -5 to +41%) and ivermectin (5%, -10 to +22%). Interruptions due to side effects were highest among participants who received zinc/vitamin C combination (6.9%), followed by vitamin C (4.7%), povidone-iodine (2.0%), and hydroxychloroquine (0.7%).

Conclusions: Chemoprophylaxis with either oral hydroxychloroquine or povidone-iodine throat spray was superior to oral vitamin C in reducing SARS-CoV-2 infection in young and healthy men.

Keywords: Hydroxychloroquine; Ivermectin; Povidone-iodine; SARS-CoV-2; Vitamin C; Zinc.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • COVID-19 / prevention & control*
  • Humans
  • Hydroxychloroquine / pharmacology*
  • Male
  • Middle Aged
  • Pharynx*
  • Povidone-Iodine / pharmacology*
  • Time Factors
  • Treatment Outcome
  • Young Adult

Substances

  • Hydroxychloroquine
  • Povidone-Iodine