Assessing the sensitivity and representativeness of the Belgian Sentinel Network of Laboratories using test reimbursement data.

BACKGROUND: The Belgian Sentinel Network of Laboratories (SNL) was created in 1983 in order to monitor trends in infectious diseases. Given the evolution of the surveillance system, such as the waivers, fusions and adhesions of laboratories over time, it is important to evaluate whether the SNL is still fit for purpose. This study aims to evaluate aspects of the sensitivity and representativeness of the SNL by means of a test coverage analysis. METHODS: We estimated test coverage of the SNL using the ratio of reimbursed tests performed by participating laboratories to the total number of tests performed between 2007 and 2012, for 12 (groups of) pathogens. We further evaluated the geographical difference coverage of the SNL at regional and provincial levels. RESULTS: We found that test coverage of the SNL was stable over time and close to, or greater than, 50 % for the 12 (groups of) pathogens studied. These results hold for the three regions of Belgium but not for all provinces. We showed that some provinces had a low test coverage for some pathogens and that test coverage was more variable over time at provincial level. CONCLUSIONS: This sensitivity and representativeness study based on test coverage suggests that the SNL is capable to describe trend and to monitor changes in the 12 (groups of) pathogens studied both at national and regional levels. Therefore, the SNL is useful to contribute to estimate the burden of disease and to inform preventive measures. It should however be reinforced to allow to be used as an alert system at provincial level

Hepatitis C virus (HCV) prevalence estimation in the adult general population in Belgium : a meta-analysis.

Although multiple HCV prevalence studies were recently performed in the general population from Belgium, they suffer from a lack of geographical representativeness, an insufficient number of participants or a lack of inclusion of high prevalence groups. The aim of this study is to provide robust information on the HCV burden. Recently performed HCV prevalence studies in the general, adult population were included in this study, based on well-defined selection criteria. A meta-analysis was performed to estimate the seroprevalence, the prevalence of participants with viremia and the prevalence estimation for people with viremia which were unaware of their status. Eight studies fulfilled the criteria for inclusion of the quantitative prevalence estimation. Based on the meta-analysis on these 8 studies, we estimated an HCV seroprevalence of 1.01% [95% CI : 0.66-1.42%], representing a total of 90,722 adult, HCV seropositives of which 64,412 individuals (0.71%) were confirmed seropositive. Based on the RNA presence, an estimated viremic prevalence of 0.33% [95% CI : 0.21-0.47 %] was determined, corresponding with 29,642 individuals. This is 46,0% of the true HCV seropositive residents. Further, based on the availability of patient information in 5 out of the 8 studies, a prevalence of 0.18% [95% CI : 0.07-0.33] representing 16,168 individuals from the adult Belgian population are unaware of their HCV status. We believe that the quantitative measurement by the meta-analysis will be more reliable for their use in the design of a screening strategy or in the development of prevention campaigns as compared to the prevalence estimations performed at local level

Distribution of HCV genotypes in Belgium from 2008 to 2015

BACKGROUND: The knowledge of circulating HCV genotypes and subtypes in a country is crucial to guide antiviral therapy and to understand local epidemiology. Studies investigating circulating HCV genotypes and their trends have been conducted in Belgium. However they are outdated, lack nationwide representativeness or were not conducted in the general population. METHODS: In order to determine the distribution of different circulating HCV genotypes in Belgium, we conducted a multicentre study with all the 19 Belgian laboratories performing reimbursed HCV genotyping assays. Available genotype and subtype data were collected for the period from 2008 till 2015. Furthermore, a limited number of other variables were collected: some demographic characteristics from the patients and the laboratory technique used for the determination of the HCV genotype. RESULTS: For the study period, 11,033 unique records collected by the participating laboratories were used for further investigation. HCV genotype 1 was the most prevalent (53.6%) genotype in Belgium, with G1a and G1b representing 19.7% and 31.6%, respectively. Genotype 3 was the next most prevalent (22.0%). Further, genotype 4, 2, and 5 were responsible for respectively 16.1%, 6.2%, and 1.9% of HCV infections. Genotype 6 and 7 comprise the remaining <1%. Throughout the years, a stable distribution was observed for most genotypes. Only for genotype 5, a decrease as a function of the year of analysis was observed, with respectively 3.6% for 2008, 2.3% for 2009 and 1.6% for the remaining years. The overall M:F ratio was 1.59 and was mainly driven by the high M:F ratio of 3.03 for patients infected with genotype 3. Patients infected with genotype 3 are also younger (mean age 41.7 years) than patients infected with other genotypes (mean age above 50 years for all genotypes). The patients for whom a genotyping assay was performed in 2008 were younger than those from 2015. Geographical distribution demonstrates that an important number of genotyped HCV patients live outside the Belgian metropolitan cities. CONCLUSION: This national monitoring study allowed a clear and objective view of the circulating HCV genotypes in Belgium and will help health authorities in the establishment of cost effectiveness determinations before implementation of new treatment strategies. This baseline characterization of the circulating genotypes is indispensable for a continuous surveillance, especially for the investigation of the possible impact of migration from endemic regions and prior to the increasing use of highly potent direct-acting antiviral (DAA) agents.status: publishe