COVID-19: Top science stories of the week, from testosterone to the latest on hydroxychloroquine

Since one of the first studies emerged in January from Wuhan, China, researchers have known that COVID-19 seems to affect men more than women. More recent studies from Italy and New York City confirm that male mortality exceeds that of women but no one knew exactly why. New evidence from different sources coming to light is pointing to androgens – male hormones such as testosterone – which seem to be helping the virus get inside cells and help to explain why males are worse affected.

Studies in Spain noted that a disproportionate number of men in hospital with COVID-19 also had male pattern baldness, which is linked to higher levels of androgens. Another study from Italy showed that men with prostate cancer who receive drugs that suppress androgens were much less likely to be infected with SARS-CoV-2. And one from the United States found a strong link between levels of androgen in the blood and the severity of COVID-19.

With no treatment yet available, researchers are now looking into testing already-approved drugs that block the effects of androgens to see if they are effective in slowing down the virus and giving the immune system time to fight back.

On Thursday, medical journal the Lancet retracted the study included in last week’s top science stories of the week that linked hydroxychloroquine to higher mortality and heart problems in COVID-19 patients. The study came under intense scrutiny when researchers and an investigation by the Guardian exposed discrepancies in the data and methods used by small US company Surgisphere to collect them. The paper’s lead author asked for the retraction after an independent audit of the data was unable to verify their accuracy.

After having temporarily paused clinical trials of the drug in response to the safety concerns the paper raised, the World Health Organization had already announced on Wednesday its data safety monitoring committee found there was no increased risk of death for COVID-19 patients taking it and that the trials would resume.

Meanwhile, another hydroxychloroquine study led by a team at the University of Minnesota, United States has found the drug does not protect people who have been exposed to the virus from becoming infected. The study was a randomised, controlled trial - the so-called “gold-standard” for measuring the effectiveness of a new medical treatment. It found that about 12% of people given hydroxychloroquine after exposure to SARS-CoV-2 developed COVID-19 within two weeks compared with about 14% of people given a placebo. This difference is not considered to be significant.

A potentially important caveat to the study noted by the authors is that COVID-19 tests were only available to trial participants who displayed symptoms - meaning that symptomless infections were not accounted for. More research is needed before a clear verdict on hydroxychloroquine's efficacy can be given.