A Randomized Trial of Hydroxychloroquine as Postexposure Prophylaxis for Covid-19
|Date||June 3, 2020|
Randomized, double-blind, placebo-controlled trial in 821 asymptomatic participants with moderate to high-risk exposure to COVID-19 showed no significantly protective effect in preventing illness onset.
This study was one of the first randomized, placebo-controlled trials assessing post-exposure prophylaxis of hydroxychloroquine.
The results have been challenged due to few participants receiving laboratory-confirmed testing for COVID-19 as well as the online survey-based nature of participant evaluation and follow-up.
This study has been criticized on the basis of so few patients receiving laboratory-confirmed testing for COVID-19. Less than one-fourth of the patients who were identified as positive COVID-19 cases were determined by laboratory testing while the vast majority of the diagnoses were made based on symptoms. While symptoms and physical exam are not a suitable replacement for PCR testing, the study was further criticized for its survey-like approach to collecting data on symptoms. No patient was seen in a controlled way by a medical professional. Rather, patients submitted their symptoms and risk factor online, and were sent either Folic acid (placebo) or hydroxychloroquine. Follow-up was also self-reported, which consisted of the patient reporting symptoms and whether or not he/she was tested for COVID-19.
Folic acid has been reported to have some in vitro effects against SARS-CoV-2. Although the evidence is minimal, it may not have been the optimal choice for a placebo in a blinded trial.
The placebo and hydroxychloroquine tablets looked nothing alike. Considering that the study consisted of healthcare professionals, it is likely that the study was not truly blinded and subjects were aware which treatment they were given. This could impact the outcome given the publicity and controversy surrounding hydroxychloroquine.
This was one of the first randomized controlled trials evaluating hydroxychloroquine for postexposure prophylaxis against COVID-19. The study impact was diminished due to the survey-like approach of the study which is reported to have been operating with a small budget of about $100,000.
No revisions reported at this time.