Summary Background Modified vaccinia virus Ankara (MVA) is a promising viral vector platform for the development of an H5N1 influenza vaccine. Preclinical assessment of MVA-based H5N1 vaccines showed ...their immunogenicity and safety in different animal models. We aimed to assess the safety and immunogenicity of the MVA-haemagglutinin-based H5N1 vaccine MVA-H5-sfMR in healthy individuals. Methods In a single-centre, double-blind phase 1/2a study, young volunteers (aged 18–28 years) were randomly assigned with a computer-generated list in equal numbers to one of eight groups and were given one injection or two injections intramuscularly at an interval of 4 weeks of a standard dose (108 plaque forming units pfu) or a ten times lower dose (107 pfu) of the MVA-H5-sfMR (vector encoding the haemagglutinin gene of influenza A/Vietnam/1194/2004 virus H5N1 subtype) or MVA-F6-sfMR (empty vector) vaccine. Volunteers and physicians who examined and administered the vaccine were masked to vaccine assignment. Individuals who received the MVA-H5-sfMR vaccine were eligible for a booster immunisation 1 year after the first immunisation. Primary endpoint was safety. Secondary outcome was immunogenicity. The trial is registered with the Dutch Trial Register, number NTR3401. Findings 79 of 80 individuals who were enrolled completed the study. No serious adverse events were identified. 11 individuals reported severe headache and lightheadedness, erythema nodosum, respiratory illness (accompanied by influenza-like symptoms), sore throat, or injection-site reaction. Most of the volunteers had one or more local (itch, pain, redness, and swelling) and systemic reactions (rise in body temperature, headache, myalgia, arthralgia, chills, malaise, and fatigue) after the first, second, and booster immunisations. Individuals who received the 107 dose had fewer systemic reactions. The MVA-H5-sfMR vaccine at 108 pfu induced significantly higher antibody responses after one and two immunisations than did 107 pfu when assessed with haemagglutination inhibition geometric mean titre at 8 weeks against H5N1 A/Vietnam/1194/2004 (30·2 SD 3·8 vs 9·2 2·3 and 108·1 2·4 vs 15·8 3·2). 27 of 39 eligible individuals were enrolled in the booster immunisation study. A single shot of MVA-H5-sfMR 108 pfu prime immunisation resulted in higher antibody responses after the booster immunisation than did two shots of MVA-H5-sfMR at the ten times lower dose. Interpretation The MVA-based H5N1 vaccine was well tolerated and immunogenic and therefore the vaccine candidates arising from the MVA platform hold great promise for rapid development in response to a future influenza pandemic threat. However, the immunogenicity of this vaccine needs to be compared with conventional H5N1 inactivated non-adjuvanted vaccine candidates in head-to-head clinical trials. Funding European Research Council.
Background. The role of environmental contamination in nosocomial cross-transmission of antibiotic-resistant bacteria has been unresolved. Using vancomycin-resistant enterococci (VRE) as a marker ...organism, we investigated the effects of improved environmental cleaning with and without promotion of hand hygiene adherence on the spread of VRE in a medical intensive care unit. Methods. The study comprised a baseline period (period 1), a period of educational intervention to improve environmental cleaning (period 2), a “washout” period without any specific intervention (period 3), and a period of multimodal hand hygiene intervention (period 4). We performed cultures for VRE of rectal swab samples obtained from patients at admission to the intensive care unit and daily thereafter, and we performed cultures of environmental samples and samples from the hands of health care workers twice weekly. We measured patient clinical and demographic variables and monitored intervention adherence frequently. Results. Our study included 748 admissions to the intensive care unit over a 9-month period. VRE acquisition rates were 33.47 cases per 1000 patient-days at risk for period 1 and 16.84, 12.09, and 10.40 cases per 1000 patient-days at risk for periods 2, 3, and 4, respectively. The mean (±SD) weekly rate of environmental sites cleaned increased from 0.48 ± 0.08 at baseline to 0.87 ± 0.08 in period 2; similarly high cleaning rates persisted in periods 3 and 4. Mean (±SD) weekly hand hygiene adherence rate was 0.40 ± 0.01 at baseline and increased to 0.57 ± 0.11 in period 2, without a specific intervention to improve adherence, but decreased to 0.29 ± 0.26 in period 3 and 0.43 ± 0.1 in period 4. Mean proportions of positive results of cultures of environmental and hand samples decreased in period 2 and remained low thereafter. In a Cox proportional hazards model, the hazard ratio for acquiring VRE during periods 2–4 was 0.36 (95% confidence interval, 0.19–0.68); the only determinant explaining the difference in VRE acquisition was admission to the intensive care unit during period 1. Conclusions. Decreasing environmental contamination may help to control the spread of some antibiotic-resistant bacteria in hospitals.
Background Direct-acting antivirals (DAAa) cure hepatitis C virus (HCV) infections in 95% of infected patients. Modeling studies predict that universal HCV treatment will lead to a decrease in the ...incidence of new infections but real-life data are lacking. The incidence of HCV among Dutch human immunodeficiency virus (HIV)–positive men who have sex with men (MSM) has been high for >10 years. In 2015 DAAs became available to all Dutch HCV patients and resulted in a rapid treatment uptake in HIV-positive MSM. We assessed whether this uptake was followed by a decrease in the incidence of HCV infections. Methods Two prospective studies of treatment for acute HCV infection enrolled patients in 17 Dutch HIV centers, having 76% of the total HIV-positive MSM population in care in the Netherlands. Patients were recruited in 2014 and 2016, the years before and after unrestricted DAA availability. We compared the HCV incidence in both years. Results The incidence of acute HCV infection decreased from 93 infections during 8290 person-years of follow-up (PYFU) in 2014 (11.2/1000 PYFU; 95% confidence interval CI, 9.1–13.7) to 49 during 8961 PYFU in 2016 (5.5/1000 PYFU; 4.1–7.2). The incidence rate ratio of 2016 compared with 2014 was 0.49 (95% CI, .35–.69). Simultaneously, a significant increase in the percentage positive syphilis (+2.2%) and gonorrhea (+2.8%) tests in HIV-positive MSM was observed at sexual health clinics across the Netherlands and contradicts a decrease in risk behavior as an alternative explanation. Conclusions Unrestricted DAA availability in the Netherlands was followed by a 51% decrease in acute HCV infections among HIV-positive MSM.
Although preventable by vaccination for more than a century, rabies virus still causes numerous fatalities every year. To determine antibody levels in humans, blood collected with a finger prick and ...applied on dried blood spot (DBS) cards is an alternative for venipuncture. The use of DBS is specifically valuable in remote areas, as it is easy to perform, store and transport. Therefore, the technique is frequently used for epidemiological studies of tropical diseases. Up to present, determination of rabies virus antibody levels on human DBS has not been validated.
We evaluated the use of human DBS for rabies serology and analyzed 99 pre- or post-vaccination serum and DBS samples with a fluorescent antibody virus neutralization test (FAVNt), which is the gold standard to detect protective antibody levels, and a Bio-Rad Platelia Rabies II ELISA. Sensitivity and specificity of DBS eluates tested with the FAVNt were 97% and 92%, respectively and 87% and 96% when tested with the Platelia-II ELISA. Antibody levels measured in serum with the FAVNt, correlated best with antibody levels measured in DBS with the FAVNt (R = 0.88).
This is the first study that applies DBS for reliable detection of human antibodies against rabies virus. Both the FAVNt and Platelia-II ELISA demonstrate an acceptable performance on DBS, providing opportunities for rabies serology in remote areas. This technique could drastically ease studies evaluating (novel) rabies vaccination strategies and monitoring persisting immunity in humans at risk, living in rabies endemic regions.
Key questions in COVID-19 are the duration and determinants of infectious virus shedding. Here, we report that infectious virus shedding is detected by virus cultures in 23 of the 129 patients ...(17.8%) hospitalized with COVID-19. The median duration of shedding infectious virus is 8 days post onset of symptoms (IQR 5-11) and drops below 5% after 15.2 days post onset of symptoms (95% confidence interval (CI) 13.4-17.2). Multivariate analyses identify viral loads above 7 log
RNA copies/mL (odds ratio OR of 14.7 (CI 3.57-58.1; p < 0.001) as independently associated with isolation of infectious SARS-CoV-2 from the respiratory tract. A serum neutralizing antibody titre of at least 1:20 (OR of 0.01 (CI 0.003-0.08; p < 0.001) is independently associated with non-infectious SARS-CoV-2. We conclude that quantitative viral RNA load assays and serological assays could be used in test-based strategies to discontinue or de-escalate infection prevention and control precautions.
HIV-1 drug resistance represents a major obstacle to infection and disease control. This retrospective study analyzes trends and determinants of resistance in antiretroviral treatment (ART)-exposed ...individuals across 7 countries in Europe. Of 20 323 cases, 80% carried at least one resistance mutation: these declined from 81% in 1997 to 71% in 2008. Predicted extensive 3-class resistance was rare (3.2% considering the cumulative genotype) and peaked at 4.5% in 2005, decreasing thereafter. The proportion of cases exhausting available drug options dropped from 32% in 2000 to 1% in 2008. Reduced risk of resistance over calendar years was confirmed by multivariable analysis.
Background: In the Netherlands, unrestricted access to direct-acting antivirals (DAAs) halved the incidence of acute hepatitis C virus (HCV) infections among HIV-infected men who have sex with men ...(MSM). To develop strategies that can further reduce the spread of HCV, it is important to understand the transmission dynamics of HCV. We used phylogenetic analysis of a dense sample of MSM to provide insight into the impact of unrestricted access to DAAs on HCV transmission in the Netherlands and in Belgium. Methods: We included 89 MSM that were recently infected with HCV genotype 1a in ten Dutch and one Belgian HIV treatment centers. Sequences were generated using next gene sequencing and Sanger sequencing. Maximum likelihood phylogenetic analysis (general time reversible model) was performed on concatenated NS5A and NS5B sequences and a reference set of 389 highly similar control sequences selected from GenBank. A cluster was based on a minimum bootstrap support of 90% and a 3% genetic distance threshold. Results: We found that 78 (88%) of individuals were part of seven major clusters. All clusters included individuals from across the study region, however, different cities were part of different clusters. In three clusters, HIV-negative MSM clustered with sequences from HIV-positive MSM. All clusters that were observed before the introduction of DAAs persisted after unrestricted access to DAAs became available. Conclusion: Recently acquired HCV infections among MSM in the Netherlands and Belgium are strongly clustered and therefore highly suitable for targeted prevention strategies, such as contact tracing and partner notification. Importantly, despite an HCV incidence reduction after high DAA uptake and continuously monitoring, HCV transmission persisted in the same clusters.
Treatment of hepatitis C virus infections (HCV) with direct acting antivirals (DAA) can prevent new infections since cured individuals cannot transmit HCV. However, as DAAs are expensive, many ...countries defer treatment to advances stages of fibrosis, which results in ongoing transmission. We assessed the epidemiological impact and cost-effectiveness of treatment initiation in different stages of infection in the Netherlands where the epidemic is mainly concentrated among HIV-infected MSMs.
We calibrated a deterministic mathematical model to the Dutch HCV epidemic among HIV-infected MSM to compare three different DAA treatment scenarios: 1) immediate treatment, 2) treatment delayed to chronic infection allowing spontaneous clearance to occur, 3) treatment delayed until F2 fibrosis stage. All scenarios are simulated from 2015 onwards. Total costs, quality adjusted life years (QALY), incremental cost-effectiveness ratios (ICERs), and epidemiological impact were calculated from a providers perspective over a lifetime horizon. We used a DAA price of €35,000 and 3% discounting rates for cost and QALYs.
Immediate DAA treatment lowers the incidence from 1.2/100 person-years to 0.2/100 person-years (interquartile range 0.1-0.2) and the prevalence from 5.0/100 person-years to 0.5/100 person-years (0.4-0.6) after 20 years. Delayed treatment awaiting spontaneous clearance will result in a similar reduction. However, further delayed treatment to F2 will increases the incidence and prevalence. Earlier treatment will cost society €68.3 and €75.1 million over a lifetime for immediate and awaiting until the chronic stage, respectively. The cost will increase if treatment is further delayed until F2 to €98.4 million. Immediate treatment will prevent 7070 new infections and gains 3419 (3019-3854) QALYs compared to F2 treatment resulting in a cost saving ICER. Treatment in the chronic stage is however dominated.
Early DAA treatment for HIV-infected MSM is an excellent and sustainable tool to meet the WHO goal of eliminating HCV in 2030.
Randomized controlled trials reported that pre-exposure prophylaxis (PrEP) with tenofovir and emtricitabine rarely selects for drug resistance. However, drug resistance due to PrEP is not completely ...understood. In daily practice, PrEP will not be used under the well-controlled conditions available in the trials, suggesting that widespread use of PrEP can result in increased drug resistance.
We surveyed expert virologists with questions about biological assumptions regarding drug resistance due to PrEP use. The influence of these assumptions on the prevalence of drug resistance and the fraction of HIV transmitted resistance was studied with a mathematical model. For comparability, 50% PrEP-coverage of and 90% per-act efficacy of PrEP in preventing HIV acquisition are assumed in all simulations.
Virologists disagreed on the following: the time until resistance emergence (range: 20-180 days) in infected PrEP users with breakthrough HIV infections; the efficacy of PrEP against drug-resistant HIV (25%-90%); and the likelihood of resistance acquisition upon transmission (10%-75%). These differences translate into projections of 0.6%- 1% and 3.5%-6% infected individuals with detectable resistance 10 years after introducing PrEP, assuming 100% and 50% adherence, respectively. The rate of resistance emergence following breakthrough HIV infection and the rate of resistance reversion after PrEP use is discontinued, were the factors identified as most influential on the expected resistance associated with PrEP. Importantly, 17-23% infected individuals could virologically fail treatment as a result of past PrEP use or transmitted resistance to PrEP with moderate adherence.
There is no broad consensus on quantification of key biological processes that underpin the emergence of PrEP-associated drug resistance. Despite this, the contribution of PrEP use to the prevalence of the detectable drug resistance is expected to be small. However, individuals who become infected despite the use of PrEP should be closely monitored due to higher risk of virological failure when initiating antiretroviral treatment in the future.
A high genetic barrier to resistance to the integrase strand transfer inhibitor (INSTI) dolutegravir has been reported in vitro and in vivo. We describe the dynamics of INSTI resistance-associated ...mutations (INSTI-RAMs) and mutations in the 3'-polypurine tract (3'-PPT) in relation to virologic failure (VF) observed in the randomized Dolutegravir as Maintenance Monotherapy for HIV-1 study (DOMONO, NCT02401828).
From 10 patients with VF, plasma samples were collected before the start of cART and during VF, and were used to generate Sanger sequences of integrase, the 5' terminal bases of the 3' long terminal repeat (LTR), and the 3'-PPT.
Median human immunodeficiency virus RNA load at VF was 3490 copies/mL (interquartile range 1440-4990 copies/mL). INSTI-RAMs (S230R, R263K, N155H, and E92Q+N155H) were detected in 4 patients, no INSTI-RAMs were detected in 4 patients, and sequencing of the integrase gene was unsuccessful in 2 patients. The time to VF ranged from 4 weeks to 72 weeks. In 1 patient, mutations developed in the highly conserved 3'-PPT. No changes in the terminal bases of the 3'-LTR were observed.
The genetic barrier to resistance is too low to justify dolutegravir maintenance monotherapy because single INSTI-RAMs are sufficient to cause VF. The large variation in time to VF suggests that stochastic reactivation of a preexisting provirus containing a single INSTI-RAM is the mechanism for failure. Changes in the 3'-PPT point to a new dolutegravir resistance mechanism in vivo.
NCT02401828.
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