What you need to know about hormones and coronavirus

It’s estimated that around 3.1 million women take the contraceptive pill in England. While the drug has long been associated with negative side-effects, such as mood swings, weight gain and migraines, new research suggests that the hormones it contains may help in the fight against coronavirus.

In a study of over half a million women undertaken by King’s College London during May and June, scientists established that those taking the combined oral contraceptive, which contains both oestrogen and progesterone, were on average 13 per cent less likely to develop serious symptoms of coronavirus.

Experts believe oestrogen could play an active role, because it has been shown to bind to immune cells and activate disease-fighting molecules. Dr Ricardo Costeira, a joint author of the study from King’s College London, said that the research showed with “relatively large numbers” the “significance of studying the sex hormone oestrogen in relation to Covid-19.”

Oestrogen has form here. Studies undertaken on SARS, a disease closely related to Covid-19, in female mice showed that blocking or removing oestrogen increased the number of inflammatory cells in the animals’ lungs, making them more likely to suffer severe effects of the disease. Meanwhile, researchers in Wuhan found that women with lower oestrogen levels tended to have more severe symptoms of Covid-19 than women with higher levels of the hormone.

It could explain why men are more likely to suffer more severe symptoms of coronavirus. A Chinese study found that the number of men who died of coronavirus was 2.4 times that of women, despite both genders having the same susceptibility to the virus.

Earlier this year, menopause specialist Dr Louise Newson identified a pattern emerging among women who are taking HRT to boost their oestrogen levels and their experiences of Covid-19. “We’ve had several women who experienced less severe symptoms of Covid 19 than their male partners,” Dr Newson told the Telegraph. “I’m wondering if a woman’s immune system when she is taking HRT is so good that it just deals with this virus more effectively.”

Dr Amalia Annaradnam, of the London Hormone Clinic, says it’s impossible to know the role that oestrogen plays in fighting off severe coronavirus at such an early stage in the research. However, she maintains that oestrogen does help to protect us from other illnesses, so it’s entirely plausible it could have an impact on Covid, too.

"People with serious cardiovascular disease, obesity and diabetes have a worse outcome with Covid," says Dr Annaradnam. "We know that oestrogen protects us against heart disease, diabetes and strokes. That’s probably why women don’t have as many of these illnesses in the run up to menopause as men do. At the menopause oestradiol levels drop and hence increase our risks of cardiovascular disease, obesity and diabetes. Replacing oestrogen at menopause can prevent against these things and perhaps lead to a better Covid outcome."

Researchers in New York are already trialling oestrogen patches on men and women to see whether the hormone has an effect on their immune response. However, Dr Annaradman maintains that we “can’t say for sure that the pill, or HRT, is going to protect people from coronavirus.” Put bluntly, plenty of women may take the contraceptive pill and still get Covid.

“There’s lots of other confounding factors at play; women on the pill are generally going to be younger, but we know that these women do a better job of fighting coronavirus than older women,” she adds.

She also advises that medications such as the combined pill and HRT slightly increase your risk of deep vein thrombosis, or a stroke. This means it could be “detrimental” for people who have other risk factors to start taking them as a way to ward off Covid-19.

“Covid has been known to cause mini clots in the blood vessels, which can lead to severe outcomes,” she says. “If you’re on hormones that already slightly increase your thrombotic risk, such as the pill or HRT, that does need to be taken into account. However, there is no need to panic and stop these medications if they’re working for you. It’s all still speculation at this stage.”

And what about men? Does the King's College study lead to the conclusion that men should consider taking the contraceptive pill to boost their Covid-fighting chances?

In a word, no. The average levels of oestrogen found in an adult man are typically 10-60 pg/ml or 10-40pg/ml depending on which type is measured. If oestrogen levels go over this reading, it can slow down sperm production, cause erectile dysfunction, and even lead to gynecomastia, a condition which causes more breast tissue to develop than normal.

“We definitely do not recommend men boost their oestrogen levels under any circumstances based on our research," says Dr Karla Lee, a researcher at Kings College London who co-led the study. "This is very early work and while interesting and hypothesis-generating, a lot more research is needed on this topic before anyone should change their behaviours."

So that's oestrogen out of the equation for men – but men have their own hormone to worry about. Research suggests that testosterone levels could potentially play a part in the severity of Covid-19. Studies point to the fact that testosterone can act as an immunosuppressant, meaning it can boost the ability of a virus to attack cells. Men with higher levels of testosterone have been shown to produce the lowest antibody responses to annual flu vaccinations. 

(This could – could – indicate why bald men seem to face a significantly higher risk of contracting severe strains of coronavirus. However, the science around the link between testosterone levels and male pattern baldness is both complex and frequently unclear.)

If high levels of testosterone are linked to an increased risk of severe symptoms, then it follows that testosterone blocking drugs, such as the anti-androgens used to treat prostate cancer, could also help in the fight against Covid. But again, beware hasty conclusions. A German study undertaken in May found that men with low testosterone levels were more likely to die of coronavirus. “The research in this area is developing rapidly,” said Dr Clive Morrison, of the Centre for Men’s Health. “Low testosterone (testosterone deficiency) appears to allow the body’s immune system to go out of control, causing what is called a ‘cytokine storm’, inflaming the lungs and leading to acute respiratory distress and in many cases, death.”

Ultimately, experts are in agreement that having balanced hormones is an important way of boosting general immunity. As Dr Annaradnam puts it, echoing an eminently sensible message we've heard repeatedly through lockdown, the key is having a “healthy diet and exercising regularly to keep your weight down and your cardiovascular system strong."

Men worried about their testosterone levels can take the Centre for Men’s Health low testosterone symptom questionnaire