Global STI Estimates Methodology Update

Methods to generate the 2012 estimates were based on those used to generate the 2005 and 2008 estimates [6 ,7 ]. There were three major changes that were implemented that arose from external expert consultations held by WHO in November 2013 and August 2014. First, the way in which countries were grouped to generate regional estimates for chlamydia, gonorrhoea and trichomoniasis was changed. In 2005 and 2008 countries were grouped into WHO regions with two regions subdivided (Africa and the Western Pacific) [6 ]. For the 2012 estimates, we defined 10 regions based on those used by the Global Burden of Disease project 2010 [10 (link)] and on epidemiology, geography and data availability (S1 Map). Second, syphilis estimates were based on country level data from the GARPR system; third, we used a Bayesian meta-analytic approach to generate the estimates and uncertainty around them.