Table 2.

Incidence of COVID-19 With Hydroxychloroquine as Pre-exposure Prophylaxis

Outcome	Placebo		Hydroxychloroquine Once Weekly			Hydroxychloroquine Twice Weekly
	No. of Infections (%)	Event Rate per Person-year (95% CI)	No. of Infections (%)	Event Rate per Person-year (95% CI)	Hazard Ratio (95% CI)	No. of Infections (%)	Event Rate per Person-year (95% CI)	Hazard Ratio (95% CI)
PCR positive or probable COVID-19	39 (7.9)	.38 (.26–.50)	29 (5.9)	.27 (.17–.37)	.72 (.44–1.16)	29 (5.9)	.28 (.18–.38)	.74 (.46–1.19)
PCR confirmed COVID-19	6 (1.2)	.06 (.01–.10)	4 (0.8)	.04 (.00–.07)	.65 (.18–2.32)	7 (1.4)	.07 (.02–.12)	1.18 (.40–3.51)
COVID-19 compatible with symptoms	38 (7.7)	.38 (.26–.49)	29 (5.9)	.28 (.18–.38)	.73 (.45–1.19)	28 (5.7)	.28 (.17–.38)	.74 (.45–1.20)

Abbreviations: CI, confidence interval; COVID-19, coronavirus disease 2019; PCR, polymerase chain reaction.