News Release

Intermingling between populations may contribute to HIV spread

Findings suggest community-based HIV prevention efforts may need to consider geographic transmission patterns if they are to effectively curb the spread of the disease

Peer-Reviewed Publication


Sexual partnerships between individuals from different communities may help explain why some community-based HIV prevention efforts were moderately effective, shows a study published in eLife.

The findings may help explain the results of some community-based prevention studies and help scientists develop better ways to track and prevent the spread of HIV.

Early identification and treatment of HIV can help prevent transmission of the virus. However, large studies of community-based universal HIV testing and treatment in sub-Saharan Africa have not been as effective as mathematical models predicted at curbing new infections.

“To stem the spread of new HIV infections, we need to better understand patterns of HIV transmission in the region,” says first author Lerato Magosi, a postdoctoral research fellow at the Center for Communicable Disease Dynamics at Harvard T. H. Chan School of Public Health, Boston, US.

Magosi and colleagues set out to learn more about HIV transmission patterns in Botswana, Africa. The team genetically sequenced HIV samples collected from 5,114 individuals in 30 communities who participated in an HIV prevention trial. This trial, called the Botswana Combination Prevention Project or Ya Tsie trial, compared HIV transmission in communities that were randomised to receive universal HIV testing and linkage to treatment with communities that did not receive such an intervention.

By identifying samples of HIV that were closely related genetically, the team was able to track how the virus spread within and between these communities. They found that most HIV transmission occurred between individuals who were about the same age and among individuals living in the same community or neighbouring communities, rather than distant communities. Viral spread from communities that did not receive the universal HIV testing and treatment intervention into communities that received the intervention was more likely to occur than vice versa.

“Our results suggest that community-based HIV testing and treatment initiatives are powerful tools to reduce HIV transmission, but will need to be supported by targeted studies aimed at closing age and sex gaps in uptake of testing and treatment,” Magosi explains.

The authors suggest that genetic sequencing may be a valuable tool to help identify geographic HIV transmission patterns. They also recommend widely distributing HIV testing and treatment interventions in communities that are likely to intermingle. “Population mobility patterns are central to understanding HIV transmission dynamics and should be considered when designing and testing HIV control strategies,” concludes senior author Marc Lipsitch, Professor of Epidemiology and Director of the Center for Communicable Disease Dynamics.


Media contact

Emily Packer, Media Relations Manager


+44 (0)1223 855373

About eLife

eLife is a non-profit organisation created by funders and led by researchers. Our mission is to accelerate discovery by operating a platform for research communication that encourages and recognises the most responsible behaviours. We review selected preprints in all areas of biology and medicine, including Genetics and Genomics, and Microbiology and Infectious Disease, while exploring creative new ways to improve how research is assessed and published. eLife receives financial support and strategic guidance from the Howard Hughes Medical Institute, the Knut and Alice Wallenberg Foundation, the Max Planck Society and Wellcome. Learn more at

To read the latest Genetics and Genomics research published in eLife, visit

And for the latest in Microbiology and Infectious Disease, see

About Harvard T.H. Chan School of Public Health

Harvard T.H. Chan School of Public Health brings together dedicated experts from many disciplines to educate new generations of global health leaders and produce powerful ideas that improve the lives and health of people everywhere. As a community of leading scientists, educators, and students, we work together to take innovative ideas from the laboratory to people’s lives – not only making scientific breakthroughs, but also working to change individual behaviours, public policies, and health care practices. Each year, more than 400 faculty members at Harvard Chan School teach 1,000-plus full-time students from around the world and train thousands more through online and executive education courses. Founded in 1913 as the Harvard-MIT School of Health Officers, the School is recognised as America’s oldest professional training program in public health.

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.