What high-risk sexual behavior is responsible for the majority of new HIV infections in developing countries?

The majority of new HIV infections in developing countries is often associated with vaginal intercourse. This mode of transmission is particularly significant due to the context in which many individuals engage in sex, such as limited access to healthcare, lack of awareness about HIV prevention, and socio-economic factors that increase vulnerability to infection.

In many developing regions, vaginal intercourse is frequently the primary sexual activity between heterosexual couples, which can contribute to high rates of infection, especially when barriers to safe sex practices, such as consistent condom use, are inadequate. Additionally, the biological susceptibility of women during vaginal intercourse, due to factors like the greater surface area exposed to potential infections and a higher likelihood of micro-tears during intercourse, further enhances the risk of HIV transmission.

While other behaviors such as anal intercourse and sharing needles are significant risk factors for HIV transmission, especially in specific populations, vaginal intercourse has emerged as the most common route of transmission in many developing regions where the epidemic is most pronounced. This understanding underscores the importance of targeted public health strategies aimed at this primary mode of transmission to effectively combat the spread of HIV.