MSU researcher is studying, raising awareness about the role of sex in the efficacy of vaccines that make use of nanomedicine.
If there's one take-home message for the general public about the coronavirus vaccines approved in the U.S., it's that they are remarkably effective.
But Michigan State University's Morteza Mahmoudi is raising awareness about an important subtlety: The vaccines developed by Moderna and Pfizer-BioNTech appear to work slightly better for men than for women.
Both vaccines use tiny orbs, or nanoparticles, to deliver their active ingredients to cells in our immune systems. For years, Mahmoudi has been studying how and why nanomedicines - therapies that use nanoparticles - can affect patients differently based on their sex and he believes this could be a factor with the vaccines.
The Johnson & Johnson vaccine has also drawn attention to sex differences because its rare blood-clotting side effect has affected predominantly women. The J&J vaccine, however, uses modified adenoviruses rather than nanoparticles to help teach our immune systems to fight off the coronavirus. That said, Mahmoudi has shown in earlier work that viruses can transfect the cells of men and women differently.
Now, he's focusing on the nanomedicine component. He's published three peer-reviewed papers calling attention to the role of sex in nanomedicine studies, both in general and as they relate to coronavirus vaccines.
"We need to monitor these sex differences and report them to the scientific community and the public," said Mahmoudi, an assistant professor in the Department of Radiology and the Precision Health Program. "It can be very helpful in developing future strategies and as we prepare for future threats."
To develop those future strategies, researchers must better understand what causes patients of different sexes to respond differently to nanomedicines, Mahmoudi said. To that end, Mahmoudi is advocating for systemic changes in how nanoparticles are used and studied in medicine with an article published May 20 in the journal Nature Communications.
In the article, he outlines four large challenges in researching the role of sex in nanomedicine performance along with strategies to mitigate them moving forward.
For example, researchers may not have sufficient resources to perform their studies in cells or other samples taken from men and women. Yet these researchers and others may still interpret their results as being equally applicable to all sexes. To prevent this from happening, Mahmoudi is calling for researchers to be more transparent and share sex-specific limitations of studies and conclusions.
"We need to be more careful about the science that gets out," Mahmoudi said. "We've witnessed that there has not been a robust consideration of sex in nanomedicine, but we need to consider sex because it is important."
Before the coronavirus pandemic, most of the research interest and funding in nanomedicine had been focused on its use in treating cancer. But nanomedicine's performance in this realm has been lackluster. Less than 15% of nanomedicines that have entered clinical trials made it through the final phase and none have proven to be better than the standard of care, Mahmoudi said.
In addition, he said, when nanomedicines are robustly studied in women, it's often because the therapies are being studied in diseases that mainly affect women, such as breast and ovarian cancers.
"Our analysis of the 41 completed clinical trial studies of therapeutic nanomedicine products revealed that 21 studies were stratified by sex because they concerned pathologies primarily found in females," Mahmoudi said. "Of the remaining 20 studies involving 851 males and 430 females, none provided sex-stratified results or indications."
Mahmoudi's team detailed these findings and m...
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