Geographical modelling and HIV transmission

Sexual interactions between people from different communities might explain why HIV prevention efforts targeting single communities weren’t as effective has expected. This is according to a study, published in eLife. 

We’ve known for some time that both early identification and early treatment of new HIV cases can prevent onwards transmission of HIV. But we’ve also seen that community based testing and treatment schemes haven’t always delivered the results expected. In order to slow the spread of HIV, and prevent new cases, we need to take into account the geographical patterns of HIV transmission.

“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.

Research

Magus and his colleagues based their research on HIV prevention schemes across 30 different African populations - including 5,114 people.

The team conducted genetic sequencing of all HIV samples available to them. By identifying HIV samples that were closely genetically related they were able to track how the virus spread within, and outside, of these communities.

Analysis showed that in most cases HIV transmission mostly occurred between people of the same age and people of the same, or neighbouring communities - rather than distant communities.

Conclusion

The authors suggest that genetic sequencing can be a valuable tool for determining geographic patterns of HIV transmission. They also suggest that HIV testing and treatment programmes cast their net wider to include communities that inter-mingle.