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

https://doi.org/10.1016/j.ijid.2021.04.035Get rights and content
Under a Creative Commons license
open access

Highlights

  • We studied chemoprophylaxis of agents that could reduce spread of SARS-CoV-2 infection.

  • Oral hydroxychloroquine and povidone-iodine throat spray reduced SARS-CoV-2 infection.

  • Oral hydroxychloroquine and povidone-iodine throat spray use were well-tolerated.

  • Infection rates did not significantly differ with oral ivermectin and zinc/vitamin C.

  • Two repurposed agents reduced spread of COVID-19 in high transmission settings.

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
Povidone-iodine
Zinc
Vitamin C
Ivermectin
SARS-CoV-2

Cited by (0)