Studies debate over effectiveness of hydroxychloroquine

New Delhi, Jan 18 Once touted as a cure for Covid, hydroxychloroquine (HCQ), the anti-malaria drug, is renewing interest as a potential treatment for the infectious disease and particularly the new fast spreading Omicron variant.

Two recent studies, not peer reviewed yet, have debated over whether HCQ is effective against Covid and Omicron. While one claims to be effective against Omicron, the other recommends against its use in Covid patients.

The first study, led by researchers from the University of Glasgow, looks at how antibodies from vaccines block Omicron from entering cells.

The researchers claim that Omicron may have changed the way it enters cells: from cell surface to via endosomes.

Since HCQ is a drug that accumulates in endosomes and makes it less acidic, it cuts Covid virus' ability to enter cells. Thus HCQ could act as an antiviral, the researchers claimed.

However, the new study did not test HCQ's effect on Omicron.

In the second study, a team of researchers Johns Hopkins Bloomberg School of Public Health, and Universities of Utah, Colorado, and Vanderbilt, among others, conducted a meta-analysis of US-based randomised clinical trials (RCTs).

The researchers analysed eight RCTs in 770 hospitalised Covid patients and compared HCQ or chloroquine (CQ) and control treatment.

The results did not show evidence of a benefit of HCQ/CQ.

"This study supports the consensus that hydroxychloroquine/chloroquine should not be used to treat hospitalised patients with Covid-19," the researchers wrote in the study.

HCQ is an anti-malaria medication more commonly used to manage the symptoms of rheumatoid arthritis and autoimmune conditions such as lupus.

In the beginning of the pandemic, the US Food and Drug Administration (FDA) had provided emergency use authorisation (EUA) for the use of HCQ and CQ in the treatment of hospitalised Covid patients.

However, most retrospective-observational studies of HCQ/CQ in hospitalised Covid patients provide no evidence supporting the efficacy of this treatment.