BALD men may be at higher risk of suffering from severe COVID-19 symptoms, emerging evidence suggests.

The link is so strong that some researchers are suggesting baldness should be considered a risk factor called the “Gabrin sign”, after the first US physician to die of COVID-19 in the United States, Dr Frank Gabrin, who was bald.

The lead author of the key study behind the association, Professor Carlos Wambier of Brown University, told the UK’s Telegraph: “We really think that baldness is a perfect predictor of severity.”

Data since the beginning of the outbreak in Wuhan, China, in January has shown that men are more likely to die after getting coronavirus. In the UK, a report this week from Public Health England found that working-age males were twice as likely as females to die after being diagnosed with COVID-19.

Until recently, scientists have been at a loss as to why this might be, pointing to factors such as lifestyle, smoking, and immune system differences between the sexes. But increasingly they believe it could be because androgens – male sex hormones like testosterone – may play a part not only in hair loss, but also in boosting the ability of coronavirus to attack cells.

This raises the possibility that treatments suppressing these hormones, such as those used for baldness as well as diseases like prostate cancer, could be used to slow the virus down, giving patients time to fight it off.

“We think androgens or male hormones are definitely the gateway for the virus to enter our cells,” said Professor Wambier.

As well as the trial being discussed using baldness drugs in the US, a separate trial has been launched by Matthew Rettig, an oncologist at UC Los Angeles, in 200 veterans in Los Angeles, Seattle, and New York, using prostate cancer drugs.

The trials follow two small studies in Spain led by Professor Wambier, which found that a disproportionately high number of men with male pattern baldness were admitted to hospital with COVID-19.

In one study, 79 per cent of the men suffering with COVID-19 in three Madrid hospitals were bald. The study of 122 patients, published in the Journal of the American Academy of Dermatology, followed an earlier piece of work among 41 patients in Spanish hospitals, which found 71 per cent were bald. The background rate of baldness in white men of a similar age to the patients studied is between 31-53 per cent. A similar correlation was found in the study among the smaller numbers of women with hair loss linked to androgens.

Other scientists said that more work needed to be done, but were excited by the potential link.

“Everybody is chasing a link between androgens …and the outcome of COVID-19,” Howard Soule, executive vice president at the Prostate Cancer Foundation, told Science Magazine.

Prostate cancer specialists are familiar with the role androgens can play in disease because in the prostate, the hormones stimulate an enzyme that boosts cancerous growth. In April, researchers published a paper in the journal Cell which showed that the enzyme TMPRSS2 is also involved in coronavirus infections.

To infect a cell, coronaviruses – including the novel SARS-CoV-2, which causes COVID-19 – use what is called a ‘spike’ protein that binds to the cell’s membrane, a process that is activated by an enzyme. In this case, it appears that TMPRSS2 may be that enzyme.

Scientists do not yet know if the enzyme responds in the same way to androgens in the lungs as it does in the prostate, but other evidence appears to support the potential link.

A study from Veneto, Italy, of 9,280 patients found that men with prostate cancer who were on androgen-deprivation therapy – drugs that cut testosterone levels – were only a quarter as likely to contract COVID-19 as men with the disease who were on other treatments.

Karen Stalbow, Head of Policy at Prostate Cancer UK, said: “There have been several recent pieces of research which indicate there may be a link between male hormones and increased risk of COVID-19. This has led some researchers to investigate whether hormone therapies commonly used to treat prostate cancer, such as enzalutamide, could reduce this risk.

“However, most of the research so far has been in the lab, and there is conflicting evidence over whether the hormone therapies have the same impact in the lungs as they would in prostate cells. There are now several clinical studies starting which hope to address these issues, but much more evidence is needed before we can know whether these hormone therapies would be an effective treatment for COVID-19.”