Women are definitely not the weaker sex when it comes to influenza (flu). A new study shows that the female sex hormone oestrogen has anti-viral properties that can do away with the influenza pathogen. The paper is published in American Journal of Physiology – Lung Cellular and Molecular Physiology.
The female hormone oestrogen was found to decrease the replication of Influenza A virus – this effect might explain why men are apparently more susceptible to flu.
The process of replication is essential for a virus to survive and propagate within and beyond its host. Its mode of infection relies on it making copies of itself inside the host’s cells so that it can get out and infect other cells, and eventually to be spread from one person to another. As pointed out by the lead author of the paper, Sabra Klein from Johns Hopkins University, the degree of replication of the virus will determine the severity of the disease, implying that if the virus replicates less, the infected person might feel less sick, and he could also be less likely to spread the virus to another person.
Oestrogen was found to affect the replicative ability of the flu virus after Klein’s team analysed its action on the latter; nasal cells, the primary target of the viral infection, were sampled from male and female participants and exposed to the virus, oestrogen, and compounds that behave like oestrogen like the environmental oestrogen bisphenol A, and selective estrogen receptor modulators (SERM).
The results showed that oestrogen, SERM compound raloxifene and bisphenol A lowered the replication of the flu virus in nasal cells taken from women. Those from the men did not exhibit this effect.
The researchers also identified the receptor protein involved in the mechanism: oestrogen provided for the anti-viral effects through oestrogen receptor beta.
These findings add to previous evidence that also suggests oestrogen has a protective effect against flu.
Klein adds that the fluctuations of the hormone throughout the menstrual cycle might make it hard to truly appraise its protective effect. Conversely, premenopausal women who are on birth control or post-menopausal women on hormone replacement might have better protection during influenza epidemics.
The researchers also believe that the application of therapeutic oestrogen currently used to treat infertility might be extended to flu treatment.