HIV can be transmitted in three main ways:

    * Sexual transmission
    * Transmission through blood
    * Mother-to-child transmission

Wherever there is HIV, all three routes of transmission will take place. However the number of infections resulting from each route will vary greatly between countries and population groups.

To be successful, an HIV prevention programme must make use of all approaches known to be effective.

For each route of transmission there are things that an individual can do to reduce or eliminate risk. There are also interventions that have been proven to work at the community, local and national level.

To be successful, an HIV prevention programme must make use of all approaches known to be effective, rather than just implementing one or a few select actions in isolation. The share of resources allocated to each area should reflect the nature of the local epidemic - for example, if most infections occur among men who have sex with men then this group should be a primary target for prevention efforts.