Preprint Open Access
Hydroxychloroquine (HCQ) has shown efficacy against COVID-19 in some but not all studies. We
hypothesized that systematic review would show HCQ to be: effective against COVID-19, more effective
when used earlier, not associated with worsening, and safe.
We searched PubMed, Cochrane, EmBase, Google Scholar, and Google for all reports on
hydroxychloroquine as a treatment for COVID-19 patients. This included pre-prints and preliminary
reports on larger COVID-19 studies. We examined the studies for efficacy, time of administration and
HCQ was found consistently effective against COVID-19 when used early, in the outpatient setting. It
was found overall effective also including inpatient studies. No unbiased study found worse outcomes
with HCQ use. No mortality or serious safety adverse event was found
HCQ is consistently effective against COVID-19 when used early in the outpatient setting, it is overall
effective against COVID-19, it has not produced worsening, it is safe.