Hydroxychloroquine Did Not Prevent Symptomatic COVID-19 in Exposed Adults
Hydroxychloroquine did not prevent symptomatic COVID-19 when given to adults after a moderate- to high-risk exposure, according to a randomized trial in the New England Journal of Medicine.
Over 800 asymptomatic North American adults (median age, 40) who reported a household or occupational exposure to a person with confirmed COVID-19 were randomized to receive hydroxychloroquine or placebo for 5 days, beginning within 4 days of exposure. Nearly 90% of the sample had high-risk exposures, defined as exposure within 6 feet for more than 10 minutes without a face mask or eye shield; the rest had moderate-risk exposures (wearing a mask but not a shield).
During 14 days’ follow-up, the incidence of illness compatible with COVID-19 (based on symptoms, confirmed by PCR testing only rarely) did not differ significantly between the hydroxychloroquine and placebo groups (12% and 14%, respectively). There was one hospitalization in each group. There were no deaths or arrhythmias.
An editorialist notes that “it is hard to be certain how many participants in the trial actually had COVID-19.” He adds, “The long delay between perceived exposure to SARS-CoV-2 and the initiation of hydroxychloroquine (≥3 days in most participants) suggests that what was being assessed was prevention of symptoms or progression of COVID-19, rather than prevention of SARS-CoV-2 infection.”