The 'myth of Hydroxychloroquine (HCQ) as post-exposure prophylaxis (PEP) for the prevention of COVID-19' is far from reality.

The efficacy of Hydroxychloroquine (HCQ) as post-exposure prophylaxis (PEP) for the prevention of COVID-19 was contentious. In this randomized control double-blind clinical trial, asymptomatic individuals with direct contact with laboratory-confirmed COVID-19 cases were randomized into PEP/HCQ (N = 574) and control/placebo (N = 594) group. The PEP/HCQ group received tablet HCQ 400 mg q 12 hourly on day one followed by 400 mg once weekly for 3 weeks, and the control/Placebo group received matching Placebo. The incidence of COVID-19 was similar (p = 0.761) in PEP [N = 24 out of 574, (4.2%)] and control [N = 27 out of 594, (4.5%)] groups. Total absolute risk reduction for the incidence of new-onset COVID-19 was -0.3% points with an overall relative risk of 0.91 (95% confidence interval, 0.52 to 1.60) and the number needed to treat (NNT) was 333 to prevent the incident of one case of COVID-19. The study found that, PEP with HCQ was not advantageous for the prevention of COVID-19 in asymptomatic individuals with high risk for SARS-CoV-2 infection. Though HCQ is a safer drug, the practice of irrational and indiscriminate use of HCQ for COVID-19 should be restrained with better pharmacovigilance.

SARS-CoV-2 infection, pulse oximetry, and interpretive caveats.

Hypoxaemia in COVID-19 does not necessarily imply COVID pneumonia or post-COVID lung fibrosis, and the caveats of finger pulse oximetry should be remembered. Drug-induced methaemoglobinemia should be considered in individuals with unexplained cyanosis, refractory hypoxaemia, or the presence of a saturation gap. Here, we share our recent encounter of 'spurious hypoxia' in a patient with COVID-19 and methaemoglobinemia.

Post-exposure prophylaxis with hydroxychloroquine for the prevention of COVID-19, a myth or a reality? The PEP-CQ Study.

Many drugs have been tried for the treatment/prevention of COVID-19 with limited success. Direct household contacts of COVID-19 patients are at highest risk for SARS-CoV-2 infection. Hydroxychloroquine (HCQ) has been tried against COVID-19 owing to its in vitro virucidal action against SARS-CoV-2, but the role of HCQ as post-exposure prophylaxis (PEP) remains inconclusive. In this open-label, controlled clinical trial, asymptomatic individuals who had direct contact with laboratory-confirmed COVID-19 cases or had undertaken international travel in the last 2 weeks were offered HCQ prophylaxis and assigned to PEP (n = 132) or control (n = 185) group. The PEP group received HCQ 800 mg on Day 1 followed by 400 mg once weekly for 3 weeks. Both groups undertook home quarantine for 2 weeks along with social distancing and personal hygiene. Over 4-week follow-up, 50/317 participants (15.8%) had new-onset COVID-19. The incidence of COVID-19 was significantly (P = 0.033) lower in the PEP (14/132; 10.6%) compared to the control (36/185; 19.5%) group (total absolute risk reduction, -8.9% points). The NNT to prevent the occurrence of 1 COVID-19 case was 12. Overall relative risk was 0.59 (95% CI 0.33-1.05). Compliance was good. The most common adverse event was epigastric discomfort with burning sensation (three participants), with no serious adverse events. PEP with HCQ has the potential for the prevention of COVID-19 in at-risk individuals. Until definitive therapy is available, continuing PEP with HCQ may be considered in suitable at-risk individuals. Further randomised clinical trials with larger samples are required for better evaluation of HCQ as PEP for COVID-19 prevention.