Friday 20 September 2019
The weaker sex
And it's not only viral infections that are higher in blokes: they are more likely to get TB, malaria, Schistosomiasis, Leishmania, Toxocara and other nematode infections. Presumably all stemming from their dozier immune response to these debilitating and potential fatal diseases.
Finally there is the evidence for vaccine response. Antibody response is greater in females for all the childhood andf teenage vaccines currently on the market except Tdap (tetanus, diphtheria, and pertussis). And in all cases where adverse reactions have been noted for a vaccine, these are more common in girls.
paper in Science [paywalled try SciHub] out of the Whitehead Institute at MIT and a 2016 paper Sex differences in immune responses in Nature Reviews Immunology. It made me look at the introductory slides of my Human Physiology course with fresh eyes. In the graphic [above] of the various biological systems I intend to cover this year the two sexes are only differentiated for Reproductive [it's the uterus, silly] and Endocrine [that pesky progesterone] systems. Osteoporosis is waaaay more common in women than men and those male cancers affect all the other systems; but not enough to upset the fundamental assumption portrayed in the diagram that men and women are essentially the same.
And the weaker sex? Surely men! We start off conceiving an substantial excess of male embryos [maybe 130 : 100] and this is whittled down to 105 : 100 at birth. The scything continues through childhood as boys succumb to fatal coughs and infections [and really dopey self-destructive risk-taking; especially when the adolescent brain cranks up between 15 and 25] to even out the ratio around the age of 30. Women out-number men in all subsequent cohorts. With women outnumbering men 5 to 1 among centenarians.