Epidemiological characterization of SARS-CoV-2 variants in children over the four COVID-19 waves and correlation with clinical presentation.

Since the start of SARS-CoV-2 pandemic, children aged ≤ 12 years have always been defined as underrepresented in terms of SARS-CoV-2 infections' frequency and severity. By correlating SARS-CoV-2 transmission dynamics with clinical and virological features in 612 SARS-CoV-2 positive patients aged ≤ 12 years, we demonstrated a sizeable circulation of different SARS-CoV-2 lineages over the four pandemic waves in paediatric population, sustained by local transmission chains. Age < 5 years, highest viral load, gamma and delta clades positively influence this local transmission. No correlations between COVID-19 manifestations and lineages or transmission chains are seen, except for a negative correlation between B.1.1.7 and hospitalization.

Resistance analysis and treatment outcomes in hepatitis C virus genotype 3-infected patients within the Italian network VIRONET-C.

AIM: This study aimed to investigate the role of resistance-associated substitutions (RASs) to direct-acting-antivirals (DAAs) in HCV genotype 3 (GT3). METHODS: Within the Italian VIRONET-C network, a total of 539 GT3-infected patients (417 DAA-naïve and 135 DAA-failures, of them, 13 at both baseline and failure) were analysed. Sanger sequencing of NS3/NS5A/NS5B was performed following home-made protocols. RESULTS: The majority of patients were male (79.4%), 91.4% were injection drug users, 49.3% were cirrhotic and 13.9% were HIV co-infected. Phylogenetic analysis classified sequences as GT3a-b-g-h (98%-0.4%-0.2%-1.2%) respectively. Overall, 135 patients failed a DAA regimen: sofosbuvir (SOF)/daclatasvir (DCV) or velpatasvir (VEL)±ribavirin (RBV) (N = 91/15) and glecaprevir (G)/pibrentasvir (P) (N = 9). Moreover, 14.8% of patients were treated with suboptimal regimens for GT3: 3D ± RBV (Paritaprevir/r + Ombitasvir+Dasabuvir, N = 15), SOF + Simeprevir (SIM) (N = 1) or SOF/Ledipasvir (LDV) ± RBV (N = 4). RAS prevalence was 15.8% in DAA-naïve patients. At failure, 81.5% patients showed at least one RAS: 11/25 (44.0%) in NS3, 109/135 (80.7%) in NS5A, 7/111 (6.3%) in NS5B SOF-failures. In NS5A-failures, Y93H RAS was the most prevalent (68.5% vs 5.1% DAA-naïve, P < .001) followed by A30K (12.7% vs 2.8% in DAA-naïve, P < .001). Analysing baseline samples, a higher prevalence of NS5A-RASs was observed before treatment in DAA-failures (5/13, 38.5%) vs DAA-naïves (61/393, 15.5%, P = .04). Regarding 228 DAA-naïve patients with an available outcome, 93.9% achieved a SVR. Interestingly, patients with baseline Y93H and/or A30K had SVR rate of 72.2% vs 95.7% for patients without NS5A-RASs (P = .002). CONCLUSIONS: In this real-life GT3 cohort, the majority of failures harboured resistant variants carrying NS5A-RASs, the most frequent being Y93H. The presence of natural NS5A-RASs before treatment was associated with failure. Further analyses are needed to confirm this observation, particularly for the new current regimens.

Cryptic HBV Replicative Activity Is Frequently Revealed in Anti-HBc-Positive/HBsAg-Negative Patients with HIV Infection by Highly Sensitive Molecular Assays, and Can Be Predicted by Integrating Classical and Novel Serological HBV Markers.

The anti-HBc-positive/HBsAg-negative status is frequent in HIV-infection and correlates with poor survival. Here, by highly-sensitive assays, we evaluate cryptic HBV replication and factors correlated with its detection in 81 anti-HBc-positive/HBsAg-negative HIV-infected patients. Patients were treated for >12 months with HBV-active modern combined antiretroviral-therapy (cART) and had serum HBV-DNA < 20 IU/mL by commercial Real-Time PCR. Serum HBV-DNA was quantified by droplet digital PCR, serum HBV-RNA by an Abbott research assay, and anti-HBc titer (proposed to infer intrahepatic cccDNA) by Lumipulse/Fujirebio. Cryptic serum HBV-DNA was detected in 29.6% of patients (median (IQR): 4(1-15) IU/mL) and serum HBV-RNA in 3.7% of patients despite HBsAg-negativity and HBV-active cART. Notably, cryptic serum HBV-DNA correlated with an advanced CDC-stage (p = 0.01) and a lower anti-HBs titer (p = 0.05), while serum HBV-RNA correlated with lower nadir CD4+ cell-count (p = 0.01). By analyzing serological HBV-markers, the combination of anti-HBs < 50 mIU/mL (indicating lower immune response) plus anti-HBc > 15COI (reflecting higher HBV replicative activity) was predictive of cryptic serum HBV-DNA (OR: 4.7(1.1-21.7), p = 0.046, PPV = 62.5%, and NPV = 72%). In conclusion, cryptic HBV-replication (not detected by classical assays) characterizes a conspicuous set of anti-HBc-positive HIV-infected patients despite HBsAg-negativity and HBV-active combined antiretroviral therapy (cART). The integration of classical and novel markers may help identify patients with cryptic HBV-replication, thus optimizing the monitoring of anti-HBc-positive/HBsAg-negative HIV-infected patients.

A Hyper-Glycosylation of HBV Surface Antigen Correlates with HBsAg-Negativity at Immunosuppression-Driven HBV Reactivation in Vivo and Hinders HBsAg Recognition in Vitro.

Immune-suppression driven Hepatitis B Virus (HBV)-reactivation poses serious concerns since it occurs in several clinical settings and can result in severe forms of hepatitis. Previous studies showed that HBV strains, circulating in patients with HBV-reactivation, are characterized by an enrichment of immune-escape mutations in HBV surface antigen (HBsAg). Here, we focused on specific immune-escape mutations associated with the acquisition of N-linked glycosylation sites in HBsAg (NLGSs). In particular, we investigated profiles of NLGSs in 47 patients with immunosuppression-driven HBV-reactivation and we evaluated their impact on HBsAg-antigenicity and HBV-replication in vitro. At HBV-reactivation, despite a median serum HBV-DNA of 6.7 [5.3-8.0] logIU/mL, 23.4% of patients remained HBsAg-negative. HBsAg-negativity at HBV-reactivation correlated with the presence of >1 additional NLGSs (p < 0.001). These NLGSs are located in the major hydrophilic region of HBsAg (known to be the target of antibodies) and resulted from the single mutation T115N, T117N, T123N, N114ins, and from the triple mutant S113N+T131N+M133T. In vitro, NLGSs strongly alter HBsAg antigenic properties and recognition by antibodies used in assays for HBsAg-quantification without affecting HBsAg-secretion and other parameters of HBV-replication. In conclusion, additional NLGSs correlate with HBsAg-negativity despite HBV-reactivation, and hamper HBsAg-antigenicity in vitro, supporting the role of NGSs in immune-escape and the importance of HBV-DNA for a proper diagnosis of HBV-reactivation.