British researchers who studied over 5,400 women with COVID during the first half of 2020 found out that those who received supplemental estrogen were 78% less likely to pass away within six months of their COVID diagnosis.

Before being diagnosed with COVID, nearly 5% of the women in the study were on hormone replacement therapy (HRT). HRT is used to treat symptoms like hot flashes and insomnia caused by low estrogen and progesterone levels during menopause.

Study author Christopher Wilcox, a primary care and population health academic clinical fellow at the University of Southampton, said that "further research would be required before we could recommend estrogen-containing medications as treatment for COVID." 

He and his colleagues do, however, note that men with COVID are more likely than women to be hospitalized and admitted to an intensive care unit. According to recent data from 38 countries, men are 1.7 times more likely than women to die from COVID.

"Quite a number of studies have shown that higher estrogen levels seem to be associated with lower severity of infectious diseases, including COVID-19," Wilcox said.

"More recently," he stressed, "there have been studies suggesting that there may be a protective effect from estrogen-containing medications, including HRT and the combined oral contraceptive pill."

Nonetheless, he added, the evidence has not been consistent.

Wilcox and his colleagues examined primary care medical records from a large UK database to learn more. By the end of June 2020, 5,451 of the more than 1.8 million women in that database had been diagnosed with COVID.

Following their COVID diagnosis, none were given HRT as a treatment, and the majority had not previously been on hormone therapy.

However, 235 patients had been on an HRT regimen for the previous six months.

The risk of dying within six months of a COVID diagnosis was higher in women who were older, obese, or suffering from other illnesses. Women taking immunosuppressive drugs were also at a higher risk of death.

However, the team determined that those on HRT faced a significantly lower risk.