BACKGROUND

Global surveillance of human immunodeficiency virus (HIV) and sexually transmitted infections (STI) is a joint effort of the World Health Organization (WHO) and the Joint United Nations Programme on HIV/ AIDS (UNAIDS). The UNAIDS/WHO Working Group on Global HIV/AIDS and STI Surveillance, initiated in November 1996, is the main coordination and implementation mechanism for UNAIDS and WHO to compile the best information available and to improve the quality of data needed for informed decision-making and planning at the national, regional and global levels.

INTRODUCTION

First generation surveillance relied solely on data on AIDS cases and some sentinel studies on HIV prevalence. In 2000, a new strategy named second generation surveillance (SGS) was promoted to tailor surveillance systems to the epidemic state of a country. More specifically, the strategy proposed the following: to concentrate strategic information resources where they would yield information that is useful in reducing the spread of HIV and in providing care for those affected; to concentrate data collection in key populations at higher risk of HIV exposure, such as populations with high levels of risk behaviour that places them at increased risk or young people at the start of their sexual lives; to compare information on HIV prevalence and on the behaviours that spread the infection to build up an informative picture of changes in the epidemic over time; to make the best use of other sources of information, such as communicable disease surveillance and reproductive health surveys, to increase understanding of the HIV epidemic and the behaviours that spread it.