Post-menopausal women may be more likely to get severely ill with coronavirus, according to research.
Researchers from King’s College London say their findings suggest high levels of oestrogen protect against Covid-19.
They analysed data from almost 600,000 women in the UK who use the COVID Symptom Study app.
People who have the app report how they feel every day, including if they develop symptoms of the coronavirus or get a test result.
Results showed post-menopausal women were 22 per cent more likely to report symptoms of Covid-19 than women who still had periods.
They were also more likely to be hospitalised and need respiratory support — an indication of severe Covid-19.
The findings suggest HRT — drugs which contain artificial oestrogen to help relieve symptoms of the menopause, such as hot flushes — may boost the immune system.
Data showed HRT appeared to lessen the severity of Covid-19 in post-menopausal women because they were less likely to need hospital care.
Younger women on the combined contraceptive pill, which contains oestrogen, also had lower rates of Covid-19 symptoms than women who did not.
Post-menopausal women may be at a higher risk of getting coronavirus, according to a recent study (stock)
Oestrogen is a sex hormone that’s responsible for the development and regulation of the female reproductive system.
Levels of oestrogen plummet in post-menopausal women and can influence how the body functions — including the immune system.
The researchers, led by Dr Ricardo Costeira, suggested oestrogen could protect against Covid-19.
This could explain why the disease and MERS — another related type of coronavirus — pose more of a threat to men more than women.
The experts wrote: ‘It has been well-illustrated that females generally mount greater inflammatory, antiviral, and humoral immune responses than males.’
They added that this contributes to better clearance of viruses, including SARS-CoV-2 — which causes Covid-19.
The study looked at 44,000 post-menopausal women who stopped having periods within the last five years. They were 53.8 years old, on average.
The average age for a woman to reach menopause – when regular periods stop – is 51.
The data of the first group was compared against 108,000 pre-menopausal women who still regularly menstruated.
Results showed that post-menopausal women were 22 per cent more likely to report Covid-19 symptoms.
They reported typical tell-tale signs of a persistent cough and loss of taste and/or smell (anosmia).
But they reported a fever, hoarse voice, loss of appetite and muscle pains at far higher levels.
Often in studies that rely on self-reporting Covid-19 symptoms say the higher the number of symptoms, the more severe the disease.
This study measured severe Covid-19 based on if the patients were hospitalised or needed respiratory support.
Post menopausal women were four per cent more likely to be hospitalised and 60 per cent more likely to need respiratory support than those still menstruating.
But the experts admitted it was not a significant difference. The findings were not published in a medical journal.
Academics did not look at whether certain groups of women were likely to catch the virus in the first place.
Older people are more vulnerable to the coronavirus because their immune systems are weaker and they cannot clear the virus as quickly.
But the researchers adjusted the results for age, as well as body mass index (BMI) and smoking which are both suspected as risk factors for Covid-19.
The link was still apparent after accounting for these risk factors.
Upon closer inspection, post-menopausal women were found to be most at risk of Covid-19 if they were aged between 45 and 50 years old.
Dr Costeira told MailOnline: ‘Based on the data we have we were unable to tease why women 45-50 were the ones driving our results.’
The three main symptoms of Covid-19 – loss of taste and/or smell, a fever and persistent cough – were all reported in higher numbers.
And the need for hospitalisation and oxygen treatment were also significantly higher.
The researchers also looked at whether infected women on hormone replacement therapy were less likely to be hospitalised.
Academics analysed a separate group of almost 151,200 women who used the Covid symptom app aged between 50 and 65.
Almost 17,800 of them used HRT, which come in the form of pills, patches and skin gels, while the others did not use any form of HRT.
Women who used HRT were 32 per cent more likely to report Covid-19 symptoms.
This may indicate they are more likely to catch the coronavirus then their HRT-free counterparts.
Or it could be an indicator of disease severity, considering young and healthy people appear to have a milder form of Covid-19 with barely any symptoms.
However, HRT-users were less likely to hospitalised or need respiratory support than those who did not take HRT.
This suggests that HRT – which contains artificial oestrogen that helps to relieve menopause symptoms – may help to boost the immune response.
However, the researchers said that the HRT results should be taken with a pinch of salt because of a lack of data.
They cautioned they didn’t know the type of HRT each women took, the way it was administered or how long they’d received it for.
Researchers also wanted to know if the contraceptive combined pill offered and form of protection against Covid-19.
The pill contains synthetic forms of the hormones oestrogen and progesterone, unlike to mini pill which only contain progesterone.
The combined pill prevents ovulation by maintaining more consistent hormone levels. It stops oestrogen levels from surging and then falling again.
Dr Costeira and colleagues looked at just over 64,200 women who used the combined pill and compared them with just over 231,400 women of the same age who did not use the pill.
Women taking the pill were 13 per cent less likely to report Covid-19 and were 21 per cent less likely to be hospitalised.
Joint lead author Dr Ricardo Costeira, from King’s College London, said: ‘Thanks to women of the COVID Symptom Study app we were able to show, with relatively large numbers, the significance of studying the sex hormone oestrogen in relation to COVID-19.
‘We hope that results from our study can help inform ongoing biomedical research and clinical trials in the field.’
The study was published on medRxiv and has not yet been peer-reviewed by other experts who may dispute the findings or the way the study was carried out.
Commenting today, independent experts said the findings were not conclusive.
Dr Edward Morris, president of the Royal College of Obstetricians and Gynaecologists, said: ‘This epidemiological study alone does not provide enough information about the impact of hormones on Covid-19 severity.’
Mr Haitham Hamoda, consultant gynaecologist and chair of the British Menopause Society, said: ‘This pre-print does not provide conclusive evidence that hormone replacement therapy (HRT) and the combined oral contraceptive pill (COCP) impact Covid-19 severity.
‘As research is limited in this area we feel that for those women currently using these preparations the benefits of HRT and COCP outweigh any possible impact that they may have on Covid-19. Overall, this is an interesting concept which requires further research.’