Improving Access to Viral Load Monitoring in HIV-infected Patients on ART in Decentralised Area Using Dried Blood Spot : Evaluation of Hepatitis C Viral Load Quantification on DBS

The "Monitoring Of Viral load In Decentralised Area" (MOVIDA) project aims at giving access to viral load (VL) monitoring to the patients coming from remote areas using Dried Blood Spot as tool of sampling.

In resource-limited settings, many biological exams are not accessible to the entire population due to logistic and financial constraints. Regarding infection with hepatitis B and C viruses (HBV and HCV), serological screening tests are easy to perform and are available nationwide in either laboratory format or rapid diagnosis tests. However, hepatitis B DNA and C RNA assessment is not available in decentralised area as no laboratory is able to perform this complex biological measurement.

WHO, in their latest guidelines, recommends using dried blood spots (DBS) as an alternative to serum or plasma. Blood is easy to collect on DBS, either after veni- or capillary puncture. Capillary blood collection can be of great interest when venipuncture is complex, for example in injecting drug users (IDUs) in whom finding an accessible vein can be difficult. Then it is easily transferred, and at a low cost as it does not require a cold chain, to a laboratory able to perform the HCV VL quantification. As of today, little is known about the performance of standard commercial HCV diagnostic assays when using DBS and none of these studies were performed in routine setting in resource-limited setting.

In Vietnam, HCV seroprevalence in the general population is estimated between 0.4% and 5%, which is much higher than the prevalence in Europe or in the US. Genotype 1 is the more prevalent in Vietnam, genotype 6 that is only found in South East Asia is the second most frequent, but other genotypes are circulating . In Vietnam, HCV prevalence is much higher in the HIV-infected population and in injecting drug users (IDUs). Currently, anti-HCV antibodies detection is available around the country even if some difficulties remain. However, access to HCV HCV viral load measurement in routine remains scarce particularly in decentralized areas because the technique is complex, expensive and need well-trained personnel and high standard of equipment. Thus, HCV viral load measurement remains non accessible to the vast majority of patients diagnosed with HCV.

This study (MOVIDA Hep) aims at evaluating the quality of HCV VL monitoring when using DBS (collection of venous and capillary blood) as compared to plasma (gold standard), in routine condition and using the existing machines. This, to find out if DBS can be used for HCV viremia confirmation in Vietnam, in the virology laboratory of the National Institute of Hygiene and Epidemiology (NIHE) in Hanoi (Vietnam) where these measurements would be performed.