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Infectious Disease Scientist Sabra Klein Studies How Viruses Impact Men and Women

Sabra Klein
Sabra Klein.

AAAS Member Sabra Klein is angry at the missed opportunities that have brought the world to this moment—when everything has been crippled by the novel coronavirus. “We should have stayed the course and developed a vaccine,” she says, her voice trailing off. “We didn’t. We shelved it.”

She believes scientists could have done more when severe acute respiratory syndrome (SARS) appeared in China in 2002 or been more responsive on the Middle East respiratory syndrome (MERS) that was first reported in Saudi Arabia in 2012 and later spread to the United States. If the scientific community had used the 2002 and 2012 coronaviruses as a test to develop a vaccine, we might not be where we are today.

Klein, a professor of molecular microbiology and immunology at the Johns Hopkins Bloomberg School of Public Health (JHBSPH), researches the differences between the male and female immune systems divorced from what she calls the ‘human condition’ or gender differences around the world that result in women not having equal access to health care and treatment. Her research in sex differences and infectious disease has implications for both men and women. For example, the interplay of a person’s hormones and how it affects the influenza virus (known as the flu), and more recently, why it appears men are more susceptible to Covid-19 infections than women.  

Klein became an infectious disease expert later in her academic life, transitioning from her background in neuroscience to microbiology and immunology. “I enjoyed neuroscience, but I found myself much more interested in the connections to the immune systems,” she says. “For my post-doctoral training, I wanted to start to work in infectious diseases so that is when I began this transition.”

Today, her research concerns infectious disease from Covid-19, to Zika infections, to HIV. Key findings in her studies indicate that females typically mount more robust immune responses than males, no matter the virus.

“If you take immune cells from HIV positive men and if you take cells from HIV positive women and you put them on a plate and you expose them to an HIV antigen,” she says, “immune cells from women are going to be much more reactive, they are going to generate a much more robust and viral response.”

Still, over a decade ago, Klein was derogatorily referred to as an ‘Immuno-Feminist,’ by alpha males in the blogsphere. She was accused of applying feminist ideas to biology by people who had disagreed with her findings that showed women had a more robust immune system than men. One of the things that surprised her most during her research, and her critics too, was that the X chromosome in women was encoded with so many genes that controlled immune functions. There were also biological differences between males and females that helped in the functioning of immune systems through a process called hormone signaling.

Estrogen, the hormone found in women, Klein argues, is responsible for altering the signaling inside of an immune cell. The hormone coaxes the cell to either start or halt making protein in an inflammatory response or when repairing body tissue.

“The benefit of women sometimes having an overactive immune response is that when it comes to things like an infection, we often fight it better,” she says.

“We know that the mortality rate in China (for Covid-19) is significantly greater for men than for women,” she says. “We really don’t know why nobody is studying how the virus replicates or the immunity that is induced but we know that more men are ending up in intensive care units.”

A growing number of papers coming out of China are now disaggregating and comparing data between men and women, a development that Klein has taken note of. “It has been very refreshing so far and it tells me that people are starting to believe that this is something that requires consideration.”

Klein is trying to get ahead of the curve by raising money to study the differences between the older men and women in Baltimore and how they will respond to the virus. “When the vaccine is available, we can study the vaccine induced immunity and compare it between men and women,” she says.

Klein thinks that the Covid-19 virus could have been avoided if there had been more surveillance of animal populations. “We have known for so long that so many emerging viruses come from bats.” But, she concedes that it is costly to monitor animals for emerging threats, pointing out that many governments do not have the appetite to keep spending money on things that do not have an immediate benefit for the people.

“You do not find anything and then you have to keep justifying spending money for which year after year you find nothing,” she notes of the difficulties.

The novel coronavirus that is currently responsible for thousands of deaths is very closely related to the one that was sequenced from bats in the mid 2000’s. Klein suggests that to halt future outbreaks, sufficient funds should be pumped into drug discoveries and vaccines now. There were some drugs that worked in the past; based on the same platform as the standard seasonal flu vaccine.

“They might not have worked great but there was some efficacy,” she says.

Klein calls out what she sees as a lack of concern for scientists that need to do their work, even during the coronavirus epidemic. She says she has had her work disrupted like so many other scientists by what she calls the “aggressive process” of shutting down operations including research facilities—something that she calls “historic for an institution like this.”

She is worried that scientists have been ordered not to start new research.

“It is stressful for all of us and you don’t know when we resume normal operations,” she says.

To learn more about Klein's thoughts on Covid-19 and its impact on men and women, check out her recent AAAS Community chat.


Owen Kibenge