Certain infectious diseases prevalent in low- and middle-income countries affect men in greater numbers than women. Such is the case with tuberculosis (TB), a public health concern in West Africa where incidence among men averages two to three times higher than among women. “The field of sex-based biology is rapidly expanding with strong evidence showing that men and women respond differently to microbial challenges, therapeutics and vaccines,” observed Dr. Djeneba Dabitao of the University of Sciences, Techniques and Technologies of Bamako. Dabitao’s Global Emerging Leader Award from Fogarty is enabling her to examine the sex differences of TB in Mali.
Dabitao hypothesizes that sex hormones influence immune responses to TB. “When you look at immune cells, most, if not all, have a receptor for hormones and we think that there is crosstalk between hormonal responses and immune responses.” Sex hormones can play a protective role in some contexts yet a pathogenic role in certain diseases. “Teasing out those different effects will provide new strategies to develop sex-specific therapies to treat or prevent infectious diseases. This means that doses of vaccines and drugs could become sex-specific in the near future,” said Dabitao.
In Mali, the rate of TB is 52 per 100,000 people, according to the WHO. Dabitao and her team have screened more than 300 people for TB and have enrolled 120 in the study. More than half have completed the protocol, which consists of a baseline visit, a check at two months after beginning treatment and a final examination at six months corresponding to the end of TB treatment. Dabitao also think that hormonal responses may not be the only explanation of the observed male bias in TB. “There could be a genetic component, too. Some immune genes located on the sex chromosomes have been involved in the pathogenesis of TB and we do not know whether they could be influencing disease outcomes in a sex-specific manner,” said Dabitao. She believes her study is proof of concept that can be used to examine pathogenesis of other major infectious diseases, such as HIV and COVID-19.
Across the globe in Vietnam, gender is a huge determining factor for tobacco consumption, behavior that poses health risks. About half of men in the country smoke, compared with only 2% of women. In the Red River Delta region, Dr. Rajani Sadasivam of the University of Massachusetts has conducted a randomized control trial of an mHealth intervention that provided smokers with counseling, Quitline phone support and nicotine replacement therapy (NRT). Imbalanced smoking rates rendered men’s participation essential to this research funded through Fogarty’s tobacco research program, with additional support from the NIH’s Office of the Director and the National Cancer Institute.
Enlisting men to participate in the study was easy, said Jessica Wijesundara, project director. “There was a lot of interest being able to access NRT.” Co-investigator Dr. Hoa Nguyen said volunteers believe their participation helps themselves and their community. Recruitment efforts relied on trusted community health workers. “They are also helpful in terms of follow-up, which reached 99%,” she said.
The intervention included six months of text messaging. “Texting is attractive to us because it’s low tech and most people can access it,” explained Sadasivam. Messages are written by both experts and peers. “Peers talk about their own experiences and are direct: ‘You will die from this.’ ‘You will get seriously ill.’ Experts cannot say things that way.”
To build capacity, the team developed a program for the Vietnamese Quitline counselors that included training with their U.S. counterparts. “We were lucky that Vietnam did a great job managing COVID-19 in their alpha period. Thus, we only had to pause for brief periods before we could resume our data collection.” said Sadasivam. Having completed data collection and qualitative interviews, the team is working on analysis and preparing results for publication. They’ve also begun another Vietnamese mHealth intervention for people living with HIV who smoke. “We will try to address not only smoking-cessation but also stigma related to HIV,” said Nguyen.