Unpacking sources of transmission in HIV prevention trials with deep-sequence pathogen data

Area of Science:

• Epidemiology
• Public Health
• Genomics

Background:

• Effective HIV prevention strategies are crucial for public health policy.
• Identifying sources of HIV infection in prevention studies is essential for policy development.
• Community-randomized trials are used to evaluate infectious disease prevention interventions.

Purpose of the Study:

• To develop a statistical approach for estimating infection sources in infectious disease prevention trials.
• To apply this approach to the Botswana Combination Prevention Project (BCPP) data.
• To assess the potential impact of national-level HIV prevention interventions.

Main Methods:

• Devised a statistical method using deep-sequenced pathogen data to estimate infection sources.
• Applied the statistical approach to data from the Botswana Combination Prevention Project (BCPP).
• Modeled the potential impact of a nationwide BCPP intervention.

Main Results:

• Estimated that 90% of new HIV infections in BCPP communities originated from outside the trial area.
• Projected a 59% reduction in transmissions if the BCPP intervention were implemented nationwide.
• Observed a 30% reduction when the intervention was limited to trial communities.

Conclusions:

• The impact of the BCPP intervention was limited by transmission sources outside the trial area.
• A nationwide implementation of the BCPP intervention could yield significantly greater reductions in HIV transmission.
• Future intervention designs should consider transmission sources beyond the intervention's immediate reach.