Many diseases, including Covid-19, can attack men and women in different ways. Why this is depends on a complex mix of biology and behavior that can be difficult to untangle.
But we do know that these differences are more likely to be considered if medical research involves female scientists, which makes the current state of scientific endeavor on Covid-19, where women are more underrepresented as authors than ever, all the more worrying.
The numbers are clear: Some 1,370 papers have been published in medical journals about Covid-19 involving 6,722 authors but only 34% of these were female, according to research published last week by Ana-Catarina Pinho-Gomes, a researcher at The George Institute for Global Health at the University of Oxford.
It’s a problem that goes beyond gender equity and fairness. It could impact how we understand the coronavirus itself, said Pinho-Gomes.
“Women’s voices are being heard less in the scientific response to the pandemic,” she said.
“Under-representation of female researchers tends to create under-representation of issues that are relevant to women in research — in our current situation this may create important gaps in our understanding of Covid-19,” the paper said.
The numbers skew a playing field that wasn’t level before the pandemic. And it’s not just female scientists underrepresented — even the lab rats are likely to be male.
First and last
Pinho-Gomes’ research, which published in the BMJ Global Health journal, also looked at the percentage of women named as first and last authors. That may seem like an arcane distinction to people outside of academia, but it’s pivotal when it comes to career progression.
Many scientists are typically credited as authors in scientific studies, but the first author is usually responsible for the bulk of the work while the last author is typically a more senior figure who acts as supervisor.
They found 29% of first authors and 26% of last authors were female.
While the underrepresentation of female authors in research has long been a problem, these figures have suggested that things have gotten worse for female scientists during the pandemic.
They highlighted a 2017 study of 1.5 million research papers, in which women comprised 40% of first authors and 27% of last authors — a higher share than they found on Covid-related papers.
While this latest research didn’t examine exactly why female researchers were publishing less during the pandemic, they suggested additional caring, parenting and homeschooling responsibilities falling to women could be exacerbating an existing male bias.
Male-biased research and Covid-19
The repercussions of this gender bias are far greater than the career prospects of individual scientists.
Women’s participation in research is linked with a greater likelihood of reporting data broken down by gender and sex — something that can improve our understanding of diseases, particularly given that Covid-19 has affected men far more adversely than women.
Gender differences may mean that men have different attitudes or behaviors such as smoking and drinking more, washing their hands less frequently and a tendency to delay seeking medical attention that affects how a disease affects them.
And when it comes to biological sex differences in immunity, we still know very little, said Adam Moeser, an associate professor of large animal clinical sciences at Michigan State University. This goes back to basic lab research, usually on mice, where females are equally underrepresented.
Male mice have been favored, he said, because of an assumption that female animals produce more variable results, potentially due to changes in sex hormones. This means that drugs and compounds that eventually advance to clinical trials in humans are based on studies in male animals.
“It is known that there are significant differences in the biology of the sexes and thus responses to same investigative drugs could be very different between a male animal vs a female animal,” Moeser said via email.
“It is possible that compounds that failed to make it to the market due to failure of efficacy in the preclinical animals research stages, could have been effective therapies in women, or vice versa,” Moeser said.
This disparity in research has only recently begun to be addressed, with the National Institutes of Health in the United States, since 2015, requiring that sex difference data be collected to qualify for a new preclinical research grants. However, Moeser said many publications are still largely reporting results from one sex.