Quantifying HIV-1 transmission due to contaminated injections

Abstract

Assessments of the importance of different routes of HIV-1 (HIV)transmission are vital for prioritization of control efforts. Lack of consistent direct data and large uncertainty in the risk of HIV transmission from HIV-contaminated injections has made quantifying the proportion of transmission caused by contaminated injections in sub-Saharan Africa difficult and unavoidably subjective. Depending on the risk assumed, estimates have ranged from 2.5% to 30% or more. We present a method based on an agestructured transmission model that allows the relative contribution of HIV-contaminated injections, and other routes of HIV transmission, to be robustly estimated, both fully quantifying and substantially reducing the associated uncertainty. To do this, we adopt a Bayesian perspective, and show how prior beliefs regarding the safety of injections and the proportion of HIV incidence due to contaminated injections should, in many cases, be substantially modified in light of age-stratified incidence and injection data, resulting in improved (posterior) estimates. Applying the method to data from rural southwest Uganda, we show that the highest estimates of the proportion of incidence due to injections are reduced from 15.5% (95% credible interval) (0.7%, 44.9%) to 5.2% (0.5%, 17.0%) if random mixing is assumed, and from 14.6% (0.7%, 42.5%) to 11.8% (1.2%, 32.5%) under assortative mixing. Lower, and more widely accepted, estimates remain largely unchanged, between 1% and 3% (0.1-6.3%). Although important uncertainty remains, our analysis shows that in rural Uganda, contaminated injections are unlikely to account for a large proportion of HIV incidence. This result is likely to be generalizable to many other populations in sub-Saharan Africa.

Needle stick injury and HIV risk among health care workers in North India

“…[6,7] In USA, 600,000-1,000,000 receive NSIs from conventional needles and sharps every year, while in UK it is 100,000 HCWs per year. [4] In India, authentic data on NSIs are scarce. It is known that around 3-6 billion injections are given per year, of which two-third injections are unsafe (62.9%) and the use of glass syringe is constantly associated with higher degree of risk.…”

“…[2] Recent studies in sub-Saharan Africa and Thailand suggest that unsafe injections are responsible for between less than 1% and 3% of all HIV infections. [3,4] An estimated 327,000 HCWs throughout the world are percutaneously exposed to HIV annually. The highest numbers of workers exposed are reported in sub-Saharan Africa and Southeast Asia.…”

Curable Sexually Transmitted Infection Treatment Interventions to Prevent HIV Transmission in Sub-Saharan Africa

“…This was recently challenged by a group of researchers who hypothesised a larger role (40% or more) for parenteral transmission [5]. However the hypothesis has since been found to be unlikely, both intellectually [6,7] and empirically, when tested in increasing numbers of studies across sub-Saharan Africa [8][9][10][11]. As there will not be a cure or vaccine against HIV for trichomoniasis alone was 12%, and that there were 69 million new cases of these STIs annually [19].…”

Patients-to-healthcare workers HIV transmission risk from sharp injuries, Southern Ethiopia

“…In sub-Saharan Africa, lack of consistent direct data and large uncertainty in the risk of HIV transmission from HIV-contaminated injections have made the quantification of the proportion of transmission caused by contaminated injections difficult and unavoidably subjective (White, Cooper Ben, Kedhar, Orroth, Biraro, Baggaley, et al 2007).…”

“…As a consequence, the risks of acquisition of HIV by percutaneous and mucocutaneous routes are estimated to be 0.32% and 0.03%, respectively. Depending on the risk assumed, the estimated proportion of transmission caused by contaminated injections in sub-Saharan Africa ranged from 2.5% to 30% or more (White, Cooper Ben, Kedhar, Orroth, Biraro, Baggaley, et al 2007). …”