Rapid, random-access, and quantification of hepatitis B virus using the Cepheid Xpert HBV viral load assay.

BACKGROUND: Monitoring viral load (VL) is an essential part of the management of patients chronically infected with hepatitis B virus (HBV). The commercial HBV VL assays currently available are generally performed on high-throughput platforms for batch wise testing of plasma samples, with relatively long turn-around-times. Rapid VL testing could provide immediate input to clinical decision making. METHODS: One hundred two stored plasma samples from 102 patients who were previously tested for HBV VL by the Cobas Ampliprep/Taqman or Cobas 4800 (Roche, Pleasanton, CA), were analyzed by the recently introduced Cepheid Xpert HBV Viral Load Assay. Thirty-one of the 102 samples were negative for HBV DNA and 71 out of 102 samples had a detectable VL. HBV DNA loads ranged from <20 to 5E8 IU/mL. HBV genotypes (A, B, C, D, E, and G) were known for 52 of the VL positive samples. Correlation of VL results between both assays was determined by the Pearson correlation coefficient (r2 ). The level of concordance was assessed using the Bland-Altman analysis. RESULTS: HBV VLs correlated well between both assays, across all genotypes (Pearson correlation coefficient r2 = 0.987). Six samples exceeded a 0.5 log difference between assays. Bland-Altman analysis demonstrated a mean of the difference of -0.107 log and a standard deviation of 0.271 log. CONCLUSION: High correlation was observed between the Roche Cobas HBV Viral Load tests and the Xpert HBV Viral Load Assay, thus enabling rapid, random access, and accurate HBV VL assessment.

REtrieval And cure of Chronic Hepatitis C (REACH): Results of micro-elimination in the Utrecht province.

BACKGROUND: The Netherlands is one of the six European countries considered on track to eliminate hepatitis C virus by 2030. To achieve this goal, continuous efforts have to be put into designing efficient case-finding strategies, including the retrieval of previously diagnosed hepatitis C virus-infected who are lost to follow-up. AIMS: To trace and treat all lost to follow-up hepatitis C virus patients in the Utrecht region and create an efficient retrieval strategy that can be used in future (national) retrieval initiatives. METHODS: Positive hepatitis C virus diagnostic tests (anti-hepatitis C virus IgG or hepatitis C virus-RNA) from the laboratory of all four hospitals and one central laboratory for primary care diagnostics in the province of Utrecht from 2001 to 2015 were linked to clinical records. Untreated patients with available contact information were deemed eligible for retrieval and invited for reevaluation with (virology) blood tests, fibroscan measurement and possible direct-acting antiviral therapy. MAIN RESULTS: After screening all hepatitis C virus diagnostics, 1913 chronic hepatitis C virus-infected were identified of which 14.1% (n = 269) were invited back into care. Overall, 17.4% was traced with the highest yield (28.3%) in those who lived in the Utrecht province. Through renewed patient assessments, 42 chronic hepatitis C virus infections were re-identified (76% with a history of intravenous drug use, 24% with Metavir F3-F4). Until now, 59% has either scheduled or initiated direct-acting antiviral therapy. CONCLUSION: The retrieval of previously diagnosed hepatitis C virus patients through screening of laboratory diagnostics from the past is feasible and should be pursued for further control and reduction of hepatitis C virus infection. Retrieval is most successful when performed regionally. LAY SUMMARY: To completely eliminate chronic hepatitis C virus (HCV) infection and prevent complications, undiagnosed and also previously diagnosed but lost to follow-up (LFU) HCV patients have to be brought (back) into care for therapy. Retrieval of LFU HCV patients through screening of laboratory diagnostics from the past is feasible and most successful when performed regionally.

Immune-escape mutations and stop-codons in HBsAg develop in a large proportion of patients with chronic HBV infection exposed to anti-HBV drugs in Europe.

BACKGROUND: HBsAg immune-escape mutations can favor HBV-transmission also in vaccinated individuals, promote immunosuppression-driven HBV-reactivation, and increase fitness of drug-resistant strains. Stop-codons can enhance HBV oncogenic-properties. Furthermore, as a consequence of the overlapping structure of HBV genome, some immune-escape mutations or stop-codons in HBsAg can derive from drug-resistance mutations in RT. This study is aimed at gaining insight in prevalence and characteristics of immune-associated escape mutations, and stop-codons in HBsAg in chronically HBV-infected patients experiencing nucleos(t)ide analogues (NA) in Europe. METHODS: This study analyzed 828 chronically HBV-infected European patients exposed to ≥ 1 NA, with detectable HBV-DNA and with an available HBsAg-sequence. The immune-associated escape mutations and the NA-induced immune-escape mutations sI195M, sI196S, and sE164D (resulting from drug-resistance mutation rtM204 V, rtM204I, and rtV173L) were retrieved from literature and examined. Mutations were defined as an aminoacid substitution with respect to a genotype A or D reference sequence. RESULTS: At least one immune-associated escape mutation was detected in 22.1% of patients with rising temporal-trend. By multivariable-analysis, genotype-D correlated with higher selection of ≥ 1 immune-associated escape mutation (OR[95%CI]:2.20[1.32-3.67], P = 0.002). In genotype-D, the presence of ≥ 1 immune-associated escape mutations was significantly higher in drug-exposed patients with drug-resistant strains than with wild-type virus (29.5% vs 20.3% P = 0.012). Result confirmed by analysing drug-naïve patients (29.5% vs 21.2%, P = 0.032). Strong correlation was observed between sP120T and rtM204I/V (P < 0.001), and their co-presence determined an increased HBV-DNA. At least one NA-induced immune-escape mutation occurred in 28.6% of patients, and their selection correlated with genotype-A (OR[95%CI]:2.03[1.32-3.10],P = 0.001). Finally, stop-codons are present in 8.4% of patients also at HBsAg-positions 172 and 182, described to enhance viral oncogenic-properties. CONCLUSIONS: Immune-escape mutations and stop-codons develop in a large fraction of NA-exposed patients from Europe. This may represent a potential threat for horizontal and vertical HBV transmission also to vaccinated persons, and fuel drug-resistance emergence.

Combined Analysis of the Prevalence of Drug-Resistant Hepatitis B Virus in Antiviral Therapy-Experienced Patients in Europe (CAPRE).

BACKGROUND: European guidelines recommend treatment of chronic hepatitis B virus infection (CHB) with the nucleos(t)ide analogs (NAs) entecavir or tenofovir. However, many European CHB patients have been exposed to other NAs, which are associated with therapy failure and resistance. The CAPRE study was performed to gain insight in prevalence and characteristics of NA resistance in Europe. METHODS: A survey was performed on genotypic resistance testing results acquired during routine monitoring of CHB patients with detectable serum hepatitis B virus DNA in European tertiary referral centers. RESULTS: Data from 1568 patients were included. The majority (73.8%) were exposed to lamivudine monotherapy. Drug-resistant strains were detected in 52.7%. The most frequently encountered primary mutation was M204V/I (48.7%), followed by A181T/V (3.8%) and N236T (2.6%). In patients exposed to entecavir (n = 102), full resistance was present in 35.3%. Independent risk factors for resistance were age, viral load, and lamivudine exposure (P < .001). CONCLUSIONS: These findings support resistance testing in cases of apparent NA therapy failure. This survey highlights the impact of exposure to lamivudine and adefovir on development of drug resistance and cross-resistance. Continued use of these NAs needs to be reconsidered at a pan-European level.

Resistance-associated polymorphisms in Dutch hepatitis C genotype 1a patients with and without HIV infection.

UNLABELLED:  Background and aim. Resistance-associated variants (RAVs) on the NS3 region of the hepatitis C virus (HCV) may be relevant for antiviral therapy, but data in human immunodeficiency virus (HIV) coinfected patients are scarce. We assessed frequencies of NS3 RAVs in patients infected with HCV genotype 1a with or without HIV coinfection. MATERIAL AND METHODS: HCV NS3 amino acids 1-181 were sequenced by the Sanger method and analyzed for RAVs. RAVs and their distribution between HCV genotype 1a clade I and II viruses were compared between HIV-infected versus HIV-uninfected patients. RESULTS: 148 samples were available (n = 68 HIV and n = 80 non-HIV). Relative frequency of clade I and clade II was significantly different between HIV (85% and 15%) and non-HIV groups (49% and 51%). Overall, HIV infected patients exhibited significantly lower prevalence of RAVs than HIV-uninfected patients (62% vs. 79%, p = 0.03). However, Q80K prevalence was significantly higher in HIV-infected subjects (50% vs. 24%, p = 0.001), whereas prevalence of S122D/G/N/S (2% vs. 16%, p = 0.002) and N174G/N/S (10% vs. 55%, p < 0.0001) polymorphisms were significantly lower. Q80K was found exclusively in clade I viruses. S122 (3% vs. 22%, p=0.001) and N174 (13% vs. 75%, p<0.0001) polymorphisms had significantly lower prevalence in clade I than clade II viruses. CONCLUSIONS: In the Netherlands, prevalence of clade I viruses and Q80K was significantly higher in HCV genotype 1a infected patients with HIV coinfection than in those without HIV coinfection. Prevalence of N174 and S122 polymorphisms was significantly higher in clade II than clade I viruses.

A genome-wide association study of hepatitis B vaccine response in an Indonesian population reveals multiple independent risk variants in the HLA region.

We performed a two-stage genome-wide association study (GWAS) of antibody titer in 3614 hepatitis B vaccine recipients from Indonesia's Riau Archipelago, leading to the identification of at least three independent signals within the human leukocyte antigen (HLA) complex. These appear to implicate HLA-DR [rs3135363; P= 6.53 × 10(-22); odds ratio (OR) = 1.53, 95% confidence interval (CI) = 1.35-1.74]; HLA-DP, previously associated with the risk of chronic hepatitis B infection (rs9277535; P= 2.91 × 10(-12); OR = 0.72, 95% CI = 0.63-0.81); and a gene rich HLA Class III interval (rs9267665; P = 1.24 × 10(-17); OR = 2.05, CI = 1.64-2.57). The substantial overlap of these variants and those identified by GWAS of chronic hepatitis B infection confirms vaccine response as a model for infection, while suggesting that the vaccine is least effective in those most at risk of lifelong infection, following exposure to the virus.

Measuring ribavirin concentrations during the earliest stages of antiviral therapy for hepatitis C: potential relevance for treatment outcome.

BACKGROUND: Correlations between ribavirin (RBV) concentrations and sustained virological response (SVR) to hepatitis C virus treatment have been demonstrated previously. As steady state is reached after several weeks of RBV treatment, dose modifications based on steady-state levels can only be applied relatively late in treatment, possibly too late to influence SVR rates. The authors aimed to determine whether measurement of early concentrations is useful to predict optimal steady-state RBV concentrations. METHODS: In 61 treatment-naive genotype 1/4 patients RBV concentrations were determined in samples collected after 1, 2, 4, 8, 12, and 24 weeks of therapy. RBV concentrations were compared between responders and nonresponders; Receiver Operating Characteristic analyses were conducted to find optimal cut-off values to predict week 8 concentrations from earlier measurements. RESULTS: Median week 8 RBV concentrations were significantly higher in patients with SVR compared with those without: 3.4 (interquartile range 2.4-3.9) versus 2.6 (interquartile range 2.0-3.5) mg/L (P < 0.05). RBV concentration at week 8 was an independent predictor of SVR [adjusted odds ratio 2.3 (95% confidence interval: 1.1-4.9; P = 0.03)]. The optimal cut-off value of week 8 RBV concentration to predict SVR was 2.20 mg/L [sensitivity 87%, specificity 40%, positive predictive value 64%, negative predictive value 71%]. Optimal cut-off values at weeks 1, 2, or 4 to predict an RBV concentration ≥2.20 mg/L at week 8 were 0.92, 1.29, and 1.67 mg/L, respectively, with positive predictive values and negative predictive values ranging from 88% to 91% and 71% to 86%, respectively. CONCLUSIONS: RBV concentrations in the earliest stages of antiviral therapy predict therapeutic steady-state concentrations, allowing timely dose adjustments with potential implications for treatment outcome.

Assessing and improving the quality of guideline-adherent hepatitis B virus care in people with HIV: A cross-sectional study.

The increasing use of non-tenofovir containing antiretroviral regimens calls for renewed attention to the prevention and management of hepatitis B virus (HBV) in people with HIV (PWH). We retrospectively assessed adherence to HBV guidelines, including complete HBV screening in PWH. In people with HIV/HBV co-infection, this included HBV therapy, screening for hepatitis delta virus (HDV) and on-therapy virologic response monitoring. HIV/HBV co-infection in PWH was defined as the presence of hepatitis B surface antigen (HBsAg) at the last measurement before study entry or detectable HBV-DNA for ≥6 months. After assessment, missing laboratory tests were performed to optimize HBV monitoring and screening for co-infections. Of all PWH under follow-up, 1484/1633 (90.9%) were adequately screened for HBV. After performing missing screening tests, 466 of 1618 PWH with complete screening results (28.8%) were non-immune for HBV infection. Fifty-one (3.2%) with HIV/HBV co-infection were identified. HBV treatment was adequate in 51/51 (100%). Screening for hepatitis A, C and delta virus antibodies and fibrosis was performed in 51/51 (100%), 49/51 (96.1%), 17/51 (35.3%) and 38/51 (74.5%). Annual HBV-DNA or HBsAg monitoring was done in 18/51 (35.3%) and hepatocellular carcinoma (HCC) surveillance in 2/9 (22.2%) of those indicated. Additional testing in those with missing data identified 4/34 (11.8%) persons with HDV antibodies and 3/30 (10%) with HBsAg seroclearance. Our study demonstrates the feasibility and added value of evaluating HBV care components and performing missing laboratory tests, identifying a large number of HBV vaccination candidates and HDV antibody screening, HBsAg monitoring and HCC surveillance as key areas for improvement.

Evaluation of a personalized, dose-sparing revaccination strategy in hepatitis B vaccine non-responders.

OBJECTIVES: The detection of low levels of antibodies against HBsAg (anti-HBs) below 10 IU/L in non-responders after a primary hepatitis B vaccination, is associated with seroconversion after revaccination. We compared the diagnostic performance of four anti-HBs assays in non-responders in their ability to differentiate between absence or presence of low levels of anti-HBs and propose a revaccination strategy guided by anti-HBs titres. METHODS: Non-responders were revaccinated with Fendrix 20 µg at 0, 1 and 2 months. Anti-HBs titres were determined by Abbott Architect, Diasorin Liaison, Roche Cobas and Siemens ADVIA Centaur. Inter-assay agreement was evaluated with Cohen's Kappa (k) in baseline samples between zero-responders without detectable antibodies and poor-responders with detectable antibodies < 10 IU/L. Seroconversion rates and geometric mean titres were analysed at 0, 1 and 3 months. A titre-based strategy (one revaccination dose and anti-HBs measurement followed by two more revaccination doses if required) was compared with the standard revaccination series of 3 doses. RESULTS: 57 participants were included in the analysis. k was ≥ 0.65 for all assays except ADVIA (k ≤ 0.41). After one revaccination dose all assays detected a mean seroconversion rate in zero-responders of 42.9%, compared to 85.1% in poor-responders. The difference between zero- and poor-responders in seroconversion rate per assay was significant (p < 0.05). After three revaccination doses the mean seroconversion rate was 88.2% in zero-responders and 98.5% in poor-responders (p > 0.286 per assay). A titre-based strategy reduced the amount of revaccinations by 17% compared with the standard. CONCLUSIONS: All assays demonstrated a comparable difference in seroconversion rate between zero- and poor-responders after one revaccination dose. The revaccination strategy could be optimised by differentiation between zero- and poor-responders followed by a titre-guided schedule.

The Netherlands Is on Track to Meet the World Health Organization Hepatitis C Elimination Targets by 2030.

BACKGROUND: The Netherlands strives for hepatitis C virus (HCV) elimination, in accordance with the World Health Organization targets. An accurate estimate when HCV elimination will be reached is elusive. We have embarked on a nationwide HCV elimination project (CELINE) that allowed us to harvest detailed data on the Dutch HCV epidemic. This study aims to provide a well-supported timeline towards HCV elimination in The Netherlands. METHODS: A previously published Markov model was used, adopting published data and unpublished CELINE project data. Two main scenarios were devised. In the Status Quo scenario, 2020 diagnosis and treatment levels remained constant in subsequent years. In the Gradual Decline scenario, an annual decrease of 10% in both diagnoses and treatments was implemented, starting in 2020. WHO incidence target was disregarded, due to low HCV incidence in The Netherlands (≤5 per 100,000). RESULTS: Following the Status Quo and Gradual Decline scenarios, The Netherlands would meet WHO's elimination targets by 2027 and 2032, respectively. From 2015 to 2030, liver-related mortality would be reduced by 97% in the Status Quo and 93% in the Gradual Decline scenario. Compared to the Status Quo scenario, the Gradual Decline scenario would result in 12 excess cases of decompensated cirrhosis, 18 excess cases of hepatocellular carcinoma, and 20 excess cases of liver-related death from 2020-2030. CONCLUSIONS: The Netherlands is on track to reach HCV elimination by 2030. However, it is vital that HCV elimination remains high on the agenda to ensure adequate numbers of patients are being diagnosed and treated.

Occupational blood exposure accidents in the Netherlands.

BACKGROUND: To make proper evaluation of prevention policies possible, data on the incidence and associated medical costs of occupational blood exposure accidents in the Netherlands are needed. METHODS: Descriptive analysis of blood exposure accidents and risk estimates for occupational groups. Costs of handling accidents were calculated. RESULTS: Each year, an estimated 13,000-15,000 blood exposure accidents are reported in the Netherlands, 95% in occupational settings. Hepatitis B (HBV) vaccination is offered free of charge only to people in risk groups, the seroprevalence of HBV, hepatitis C (HCV) and human immunodeficiency virus (HIV) is low and few infections are related to blood exposure accidents. High-risk accidents occur mainly in hospitals. In nursing homes and home care settings, the majority of the accidents are low-risk. Limited data are available about occurrence of accidents in other occupational groups. Associated medical costs from occupational blood exposure accidents are mainly determined by the initial risk management. CONCLUSIONS: Accidents must be managed effectively to prevent infection and reduce anxiety in injured employees. While strategies to reduce HCV and HIV infection should be primarily aimed at reducing the occurrence of high-risk accidents, vaccination can prevent HBV infection and cut the costs of handling low-risk accidents. The implementation of vaccination strategies, safe working policies and the proper use of safe equipment should be monitored better.

Immunity against measles, mumps, rubella, varicella, diphtheria, tetanus, polio, hepatitis A and hepatitis B among adult asylum seekers in the Netherlands, 2016.

Asylum seekers are a vulnerable population for contracting infectious diseases. Outbreaks occur among children and adults. In the Netherlands, asylum seeker children are offered vaccination according to the National Immunization Program. Little is known about protection against vaccine-preventable diseases (VPD) in adult asylum seekers. In this 2016 study, we assessed the immunity of adult asylum seekers against nine VPD to identify groups that might benefit from additional vaccinations. We invited asylum seekers from Syria, Iran, Iraq, Afghanistan, Eritrea and Ethiopia to participate in a serosurvey. Participants provided informed consent and a blood sample, and completed a questionnaire. We measured prevalence of protective antibodies to measles, mumps, rubella, varicella, diphtheria, tetanus, polio type 1-3 and hepatitis A and B, stratified them by country of origin and age groups. The median age of the 622 participants was 28 years (interquartile range: 23-35), 81% were male and 48% originated from Syria. Overall, seroprotection was 88% for measles (range between countries: 83-93%), 91% for mumps (81-95%), 94% for rubella (84-98%), 96% for varicella (92-98%), 82% for diphtheria (65-88%), 98% for tetanus (86-100%), 91% (88-94%) for polio type 1, 95% (90-98%) for polio type 2, 82% (76-86%) for polio type 3, 84% (54-100%) for hepatitis A and 27% for hepatitis B (anti-HBs; 8-42%). Our results indicate insufficient protection against certain VPD in some subgroups. For all countries except Eritrea, measles seroprotection was below the 95% threshold required for elimination. Measles seroprevalence was lowest among adults younger than 25 years. In comparison, seroprevalence in the Dutch general population was 96% in 2006/07. The results of this study can help prioritizing vaccination of susceptible subgroups of adult asylum seekers, in general and in outbreak situations.

Kinetics of Meningococcal Serogroup C-Specific Functional Antibody Levels Up to 15 Years after a Single Immunization with a Meningococcal Serogroup C Conjugate Vaccine during Adolescence.

Adolescent vaccination is now considered the key factor for offering direct protection against meningococcal disease but also for reducing carriage and transmission and, in this way, establishing herd protection. This study estimated age-dependent patterns in functional meningococcal serogroup C (MenC) antibody kinetics after primary MenC conjugate (MenCC) vaccination in adolescents. Serum samples (n = 1,676) were drawn from 2006 to 2011 from individuals aged 9 to 18 years at the time of primary MenCC vaccination in 2002. Functional antibody levels were measured with a serum bactericidal antibody assay (SBA) using rabbit complement. SBA titers gradually declined with time. Up to 9 years after primary vaccination, SBA titers were estimated to be higher in individuals who were aged 13 to 18 years at priming than in those who were aged 9 to 10 years at priming. Based on a linear mixed model, the higher functional antibody levels with age seem to be due to the achievement of higher peak levels upon vaccination rather than to lower rates of decline. It is estimated that 35 to 50% of individuals who received a single primary MenCC vaccination at an age of 9 to 18 years in 2002 will still have sufficient protective antibody levels 15 years later. Using a linear mixed model based on cohort data for a single dated serum sample per person, we were able to estimate the level of protection against MenC up to 15 years after a single vaccination. The current study shows that analysis of antibody kinetics can be done using cross-sectional serology data and is therefore relevant for future serosurveillance studies.

The hepatitis C virus nonstructural protein 3 Q80K polymorphism is frequently detected and transmitted among HIV-infected MSM in the Netherlands.

OBJECTIVES: The Q80K polymorphism is a naturally occurring resistance-associated variant in the hepatitis C virus (HCV) nonstructural protein 3 (NS3) region and is likely transmissible between hosts. This study describes the Q80K origin and prevalence among HCV risk groups in the Netherlands and examines whether Q80K is linked to specific transmission networks. DESIGN AND METHODS: Stored blood samples from HCV genotype 1a-infected patients were used for PCR and sequencing to reconstruct the NS3 maximum likelihood phylogeny. The most recent common ancestor was estimated with a coalescent-based model within a Bayesian statistical framework. RESULTS: Study participants (n = 150) were either MSM (39%), people who inject drugs (17%), or patients with other (15%) or unknown/unreported (29%) risk behavior. Overall 45% was coinfected with HIV. Q80K was present in 36% (95% confidence interval 28-44%) of patients throughout the sample collection period (2000-2015) and was most prevalent in MSM (52%, 95% confidence interval 38-65%). Five MSM-specific transmission clusters were identified, of which three exclusively contained sequences with Q80K. The HCV-1a most recent common ancestor in the Netherlands was estimated in 1914 (95% higher posterior density 1879-1944) and Q80K originated in 1957 (95% higher posterior density 1942-1970) within HCV-1a clade I. All Q80K lineages could be traced back to this single origin. CONCLUSION: Q80K is a highly stable and transmissible resistance-associated variant and was present in a large part of Dutch HIV-coinfected MSM. The introduction and expansion of Q80K variants in this key population suggest a founder effect, potentially jeopardizing future treatment with simeprevir.

Mumps-specific cross-neutralization by MMR vaccine-induced antibodies predicts protection against mumps virus infection.

BACKGROUND: Similar to other recent mumps genotype G outbreaks worldwide, most mumps patients during the recent mumps genotype G outbreaks in the Netherlands had received 2 doses of measles, mumps and rubella (MMR) vaccine during childhood. Here, we investigate the capacity of vaccine-induced antibodies to neutralize wild type mumps virus strains, including mumps virus genotype G. METHODS: In this study, we tested 105 pre-outbreak serum samples from students who had received 2 MMR vaccine doses and who had no mumps virus infection (n=76), symptomatic mumps virus infection (n=10) or asymptomatic mumps virus infection (n=19) during the mumps outbreaks. In all samples, mumps-specific IgG concentrations were measured by multiplex immunoassay and neutralization titers were measured against the Jeryl Lynn vaccine strain and against wild type genotype G and genotype D mumps virus strains. RESULTS: The correlation between mumps-specific IgG concentrations and neutralization titers against Jeryl Lynn was poor, which suggests that IgG concentrations do not adequately represent immunological protection against mumps virus infection by antibody neutralization. Pre-outbreak neutralization titers in infected persons were significantly lower against genotype G than against the vaccine strain. Furthermore, antibody neutralization of wild type mumps virus genotype G and genotype D was significantly reduced in pre-outbreak samples from infected persons as compared with non-infected persons. No statistically significant difference was found for the vaccine strain. The sensitivity/specificity ratio was largest for neutralization of the genotype G strain as compared with the genotype D strain and the vaccine strain. CONCLUSIONS: The reduced neutralization of wild type mumps virus strains in MMR vaccinated persons prior to infection indicates that pre-outbreak mumps virus neutralization is partly strain-specific and that neutralization differs between infected and non-infected persons. Therefore, we recommend the use of wild type mumps virus neutralization assays as preferred tool for surveillance of protection against mumps virus infection.

UVB exposure impairs immune responses after hepatitis B vaccination in two different mouse strains.

Ultraviolet light exposure can impair immune responses that are not restricted to the exposed skin but is also found at other sites, i.e. systemic immunosuppression. Therefore, we investigated the UV-induced modulating effects on vaccination against hepatitis B in a mouse model. Two different mouse strains, BALB/c and C57B1/ 6, were vaccinated intramuscularly against hepatitis B. Mice were exposed to different doses of ultraviolet B (UVB) for five consecutive days on shaved back skin before the vaccination. Vaccination against hepatitis B induced cellular (delayed-type hypersensitivity [DTH] and lymphocyte stimulation test) as well as humoral immune responses in both mouse strains. The DTH responses in C57BB1/6 mice were statistically significantly higher compared with BALB/c mice. UVB exposure induced a dose-dependent suppression of cellular immunity in both strains of mice. C57B1/6 mice seemed to be more susceptible to this suppression. Anti-hepatitis B surface antibodies (total-Ig) were only marginally suppressed after UVB exposure. IgG2a and interferon-gamma levels, both indicators for Th1 immune response, were suppressed in both mouse strains after UVB exposure. In summary, UVB exposure induced a dose-dependent suppression of both cellular and humoral immune responses after hepatitis B vaccination, although the suppressive effects on humoral immunity were limited to IgG2a production. Susceptibility to UVB-induced immunomodulation depended on the strain of mice and their predilection for developing different T cell responses.

Epidermal cis-urocanic acid levels correlate with lower specific cellular immune responses after hepatitis B vaccination of ultraviolet B-exposed humans.

Urocanic acid (UCA) is a major UV-absorbing chromophore in the epidermis and has been suggested to act as one of the initiators of UV-induced immunosuppression. cis-UCA, the isomer from UCA that is formed upon UV exposure, has been shown to impair some cellular immune responses. cis-UCA levels were determined in a study in which the influence of ultraviolet B (UVB) exposure on immune responses after hepatitis B vaccination in human volunteers was established. A significant increase in cis-UCA levels was found in the skin of UVB-exposed volunteers compared with controls. cis-UCA levels, calculated as the percentage of the total UCA amount, in UVB-exposed volunteers correlated significantly with the cumulative UVB dose received in 5 consecutive days, i.e. the higher the UVB dose (J/m2), the higher the cis-UCA levels (until a cis-UCA plateau was reached in the so-called photostationary state). Correlations between skin cis-UCA levels and immune responses were determined, and they revealed no statistically significant correlations among lymphocyte proliferation responses after either mitogenic stimulation or stimulation with recall antigens. No correlation was found between cis-UCA levels and hepatitis B-specific antibody titers. However, we found a statistically significant negative correlation between cis-UCA levels and hepatitis B-specific lymphocyte proliferation responses when volunteers were irradiated with UVB before hepatitis B vaccination. In other words, volunteers with high cis-UCA levels caused by UVB exposure showed lower cellular immune responses against hepatitis B antigen after hepatitis B vaccination.

Long-term persistence of T cell memory to HBsAg after hepatitis B vaccination.

AIM: To determine if the T cell memory to HBsAg can persist for a long time after hepatitis B (HB) vaccination. METHODS: Thirty one vaccine recipients who were healthcare workers (18 females and 13 males aged 34-58 years) from Utrecht University Hospital, Netherlands, and had previously received a standard course of vaccination for hepatitis B were investigated and another 9 unvaccinated healthy volunteers from the same hospital were used as the control. Blood samples were taken just before the experiment to test serum anti-HBs levels and the subjects were classified into different groups according to their serum titers of anti-HBs and vaccination history. Their peripheral blood mononuclear cells (PBMC) were isolated from freshly heparinized venous blood and the proliferative response of T lymphocytes to the recombinant hepatitis B surface antigen (HBsAg) was investigated. RESULTS: Positive serum anti-HBs was found in 61.3% (19/31) vaccine recipients and a significant in vitro lymphocyte proliferative response to recombinant HBsAg was observed in all the vaccinees with positive anti-HBs. Serum anti-HBs level < or =10 IU/L was found in 38.7% (12/31) subjects. In this study, we specially focused on lymphocyte proliferative response to recombinant HBsAg in those vaccine recipients with serum anti-HBsAg less than 10 IU/L. Most of them had received a standard course of vaccination about 10 years before. T lymphocyte proliferative response was found positive in 7 of the 12 vaccine recipients. These results confirmed that HBsAg-specific memory T cells remained detectable in the circulation for a long time after vaccination, even when serum anti-HBs level had been undetectable. CONCLUSION: The T cell memory to HBsAg can persist for at least 10 years after HB vaccination. Further booster injection is not necessary in healthy responders to HB vaccine.

Is a low dose of hepatitis B vaccine enough for a rapid vaccination scheme?

AIM: To determine whether or not a low dose of HB vaccine can be effectively used in the rapid vaccination. METHODS: Rapid vaccination (0, 1, 2 months) with low dose (5 microg) or routine dose (10 microg) HB vaccine was studied in 250 subjects (130 school children and 120 university students). Serum from all the participants was tested for HBsAg, anti-HBs and anti-HBc at 1, 3 and 7 months after the first dose of vaccination and all subjects were serum HBV marks negative before the vaccination. Non-responders to a complete initial vaccination from university students were given an additional vaccination with 10 microg of HB vaccine and their serum anti-HBs was tested again one month later. RESULTS: One month after the third dose of vaccination (third month) sero-conversion rates and geometric mean titer (GMTs) were significantly (P<0.01) higher in the routine dose (resp. 89% and 106.8) than in the low dose group (resp. 72% and 59.5). Sero-conversion rates and GMTs were maintained stable for another 4 months in both groups. After an additional vaccination to non-responders with 10 microg HB vaccine, 17/23 subjects (13/15 from those vaccinated with 5 microg vaccine and 4/8 from those vaccinated with 10 microg vaccine) became anti-HBs positive, yielding similar sero-conversion rates for both dose groups. CONCLUSION: Higher sero-conversion rates and GMTs were reached in those vaccinated with 10 microg HB vaccine than in those vaccinated with 5 microg HB vaccine after a complete vaccination with a 0, 1, 2 month scheme. But the subjects vaccinated with 5 microg vaccine can also reach the similar sero-conversion rate after an additional vaccination.

Transmission profile of hepatitis B virus infection in the Batam region, Indonesia. Evidence for a predominantly horizontal transmission profile.

The aim of this study was to describe the distribution of hepatitis B virus markers among the autochthonous and immigrant multicultural populations of Riau province, Indonesia, in order to define the groups at risk and their infrastructure. This investigation was part of a large hepatitis B vaccination study. A total of 9701 healthy individuals, aged 5 years or older and living in the urbanised area of Batam, near Singapore, and on the surrounding islands were included. Socio-epidemiological data were collected, blood was drawn, and sera were tested for antibodies to hepatitis B core (anti-HBc) and surface antigen (anti-HBs). Anti-HBc-positive sera were tested against hepatitis B surface antigen (HBsAg). All tests comprised immunoassays from Roche (Germany) using Elecsys 2010. Complete data were available from 9314 subjects. The results showed relatively low prevalences of anti-HBc (a marker of a previous hepatitis B infection) and HBsAg in the 5-year-old chiLdren (5.8 and 1.9%, respectively) that increased continuously with increasing age. High anti-HBs levels (>1000 IU/L) were found in all age cohorts, indicating a lifelong threat of active hepatitis B infection. In conclusion, the transmission profile of hepatitis B appeared to be mainly horizontal (person-to-person) in the highly endemic region studied. Vertical transmission was less than 5%. The horizontal transmission routes included non-sexual activities of life since children <10 years of age also showed considerable infection rates. The results underline the need for catch-up hepatitis B vaccination programs for children and adults.