Estimating the size of the population of persons who inject drugs in the island of Montréal, Canada, using a six-source capture-recapture model

The 2009-2010 estimate represents a two-third reduction compared to the one for 1996. The multisource capture-recapture method is useful to produce estimates of the size of the PWID population. It is of particular interest when conducted at regular intervals thus allowing for close monitoring of the injection phenomenon.