Evolution of the residual risk of HBV, HCV and HIV transmission through blood transfusion in the Region of Valencia, Spain, during a 15-year period (2003-2017)

Abstract

Background. Towards the end of the 20^th century, transfusion-transmitted viral infections (TTVI) represented a huge problem for public health. From the beginning of the screening of blood donations, this risk has decreased to the point that it is no longer possible to measure it directly and it is necessary to use mathematical models. Using one of these models, the aim of this study was to analyse the evolution of the residual risk of hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV) transmission through blood transfusion from 2003 to 2017 in the Region of Valencia, Spain.
Materials and methods. Using data from the Blood Transfusion Centre of the Valencian Community, the incidence rate in donors and the residual risk were calculated for each agent and year by applying the most updated version of the incidence/window period model. For the set of the three viruses, these magnitudes were calculated as the algebraic sum of the specifics ones for each of them. The evolution of both magnitudes was analysed by the Mann-Kendall trend test and the Sen estimation of trend slope.
Results. The residual risks obtained vary depending on the agent and the year. Considering the three viruses jointly, they range from 1 per 360,380 to 1 per 44,715 donations. During the study period, there was a statistically significant downward trend in the incidence rate of HBV (p<0.05, trend slope −0.88), the residual risk of HBV (p<0.0005, slope −0.98), and the joint residual risk for the three viruses (p<0.0001, slope −0.99).
Discussion. The current risk of TTVI is very low in the Region of Valencia. In the last 15 years, there has been a reduction in the donor incidence rate and in the residual risk for the case of HBV; such a reduction cannot be confirmed for HCV and HIV. Consideration of the three viruses jointly confirms a reduction in the residual risk; we are unable to establish whether the evolution of the joint incidence rate has contributed to this reduction or whether it is due only to the shortening of window periods.