[Evolution of the need and coverage of syringe exchange programs in Spanish prisons, 1992-2009: A revised estimation].

INTRODUCTION The objective of this paper is to amend the bias included in our previous work, presenting a corrected estimation of the need and coverage of syringes/needles in Spanish prisons between 1992 and 2009. METHODS Data on the provision of the needles exchange programs (NEPs) in prison is taken from official publications. The need was calculated by applying multiplicative methods to secondary data from several sources. Coverage was estimated as the quotient between provision and need and the difference between these magnitudes. The detected need estimate bias has been corrected. RESULTS NEP's in prisons started in 1997. Their maximum coverage reached 36% in 2005, which is much higher than the initially estimated value. However, it decreased by half in the next four years, reaching 17.4% in 2009. CONCLUSION The remarkable coverage reached by these programmes must be valued, but more recent evolution leads us to emphasize the need to be imaginative so that new epidemiological and economic circumstances do not lead to their disappearance.