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. 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. 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. 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.

We studied the secondary attack rate (SAR), risk factors, and precautionary practices of household transmission in a prospective, longitudinal study. We further compared transmission between the Alpha (B.1.1.7) variant and non-Variant of Concern (non-VOC) viruses. From May 2020 throughout April 2021, we recruited 70 confirmed COVID-19 cases with 146 household contacts. Participants donated biological samples eight times over 6 weeks and answered questionnaires. SARS-CoV-2 infection was detected by real-time RT-PCR. Whole genome sequencing and droplet digital PCR were used to establish virus variant and viral load. SARS-CoV-2 transmission occurred in 60% of the households, and the overall SAR for household contacts was 50%. The SAR was significantly higher for the Alpha variant (78%) compared with non-VOC viruses (43%) and was associated with a higher viral load. SAR was higher in household contacts aged ≥40 years (69%) than in younger contacts (40–47%), and for contacts of primary cases with loss of taste/smell. Children had lower viral loads and were more often asymptomatic than adults. Sleeping separately from the primary case reduced the risk of transmission. In conclusion, we found substantial household transmission, particularly for the Alpha variant. Precautionary practices seem to reduce SAR, but preventing household transmission may become difficult with more contagious variants, depending on vaccine use and effectiveness.

Hepatitis E virus (HEV) is the most common cause of acute viral hepatitis worldwide. In many low-income countries it causes large outbreaks and disproportionally affects pregnant women and their offspring. Surveillance studies to find effective preventive interventions are needed but are hampered by the lack of funding and infrastructure. Dried blood spots (DBS) offer an easier and more robust way to collect, transport, and store blood samples compared to plasma/serum samples, and could ease some of the barriers for such studies. In this study we optimize an HEV IgG ELISA for DBS samples and validate it on 300 paired DBS and plasma samples collected in rural areas of Bangladesh from participants in a HEV vaccine study. We demonstrate that HEV IgG in blood stored as DBS is stable for two months at up to 40 °C, and for five freeze-thaw cycles. The specificity was 97% and the overall sensitivity of the DBS assay was 81%. The sensitivity was higher in samples from vaccinated participants (100%) compared to previously infected participants (59%), reflecting a positive correlation between IgG titer and sensitivity. We found a strong correlation between DBS and plasma samples with an r2 of 0.90, but with a higher degree of difference between individual paired samples. Our study shows that DBS offers a stable alternative to plasma/serum for HEV IgG measurements and can facilitate serological studies, particularly in resource limited areas.

High viral load and positive hepatitis B e-antigen (HBeAg) results are risk factors for mother-to-child transmission (MTCT) of hepatitis B virus (HBV). In sub-Saharan Africa, little is known about the distribution of these risk factors, as well as early childhood HBV transmission. In this study, Ethiopian women aged 18–45 years with chronic hepatitis B were assessed for the presence of HBeAg and high viral load. Their children below 4 years of age were invited for assessment of viral markers, defining active HBV infection as a positive hepatitis B s-antigen (HBsAg) and/or detectable HBV DNA. In total, 61 of 428 HBV-infected women (14.3%) had a positive HBeAg result and/or a high viral load. Of note, 26 of 49 women (53.1%) with viral load above 200,000 IU/mL were HBeAg negative. Among 89 children born of HBV-infected mothers (median age 20 months), 9 (10.1%) had evidence of active HBV infection. In conclusion, one in seven women with chronic hepatitis B had risk factors for MTCT, and HBeAg was a poor predictor of high viral load. One in ten children born of HBV-infected women acquired HBV-infection despite completing their scheduled HBV vaccination at 6, 10 and 14 weeks of age.

Hepatitis B virus (HBV) infection remains a serious global health challenge. The widespread distribution of HBV is highlighted by multiple HBV genotypes associated with different geographical origin and transmission patterns, as well as, clinical outcomes. Investigating population HBV genotype composition and origin is therefore highly warranted. In this molecular epidemiological study we analysed 1157 HBV S-gene sequences collected from patients in Norway, primarily in the period 2004–2011, and linked them to epidemiological data from the Norwegian surveillance system for communicable diseases. Of the patients with reported country of infection (n = 909), 10% (n = 93) were infected in Norway, but the majority (n = 816; 90%) stated that they became infected outside of Norway. Of the patients infected outside of Norway, most became infected in Southeast and East Asia (n = 465; 51%) and Central, West, and North Africa (n = 254; 28%). The distribution of HBV genotypes in Norway is dominated by genotype D (32%) followed by genotype A (22%), B and C (18 and 18%, respectively), and E (7%). Genotype B, C and E were phylogenetically categorized by a majority of sequences originating from distinct geographical regions, either Asia or Africa, whereas genotype A and D originated from multiple geographic regions. However, within genotype A and D, our molecular epidemiology analysis indicated a geographical clustering of sequences depending on their geographical origin. The majority of HBV patients in Norway became infected outside of Norway and were represented by most common genotypes. Patients stated to have been infected in Norway were found primarily within genotype A and D, and were phylogenetically characterized by both small local clusters and interspersed sequences that clustered with non-Norwegian sequences, indicating that a proportion of the patients assumed to have been infected in Norway likely became infected outside of Norway although assumed the contrary.

The discovery of autochthonous hepatitis E in industrialized countries has changed the understanding of hepatitis E virus (HEV) infection in these regions, now known to be mainly due to zoonotic transmission of genotype 3. The foodborne route of transmission via consumption of contaminated meat from HEV infected pigs is well documented as well as the direct occupational exposure to animal reservoirs. Accumulating evidence also points to an emerging potential threat to blood safety after the identification of viremic blood donors and the documentation of HEV-contaminated blood or blood products. Moreover, the origin of several iatrogenic cases remains unclear and porcine-derived pharmaceutic products have been suspected as a cause. Severe morbidity following HEV infection in patients receiving immunosuppressive therapy and in those with severe immunodeficiency from other causes has been recently recognized as a serious consequence of this infection in industrialized countries. In Portugal no large-scale HEV seroprevalence study has been undertaken, no professional risk groups have been identified, and the risk of blood donation from HEV silent infected donors is unknown. The present paper describes seroepidemiological and molecular approaches to answer these questions. To address these issues a study protocol was designed that will approach: i) the seroprevalence of HEV among the Portuguese general population; ii) HEV infection among butchers and slaughterhouse workers (occupational risk); iii) the silent HEV infection in Portuguese blood donors (HEV transfusion-associated risk); iv) the potential HEV contamination of porcine-derived pharmaceutical products. Commercial enzyme immunoassays and real-time/conventional RT-PCR assays will be used. This study is the first evaluation of the seroepidemiological status to HEV infection of the Portuguese population, the first to potentially identify professional risk groups, and to evaluate the safety of blood and blood products and porcine-derived pharmaceutics in Portugal. It will generate valuable data applicable for preventive and control measures against HEV infection (e.g., introduction of systematic screening of blood donors, control of blood products or porcine derived pharmaceutical products), thus helping to manage the burden of this viral disease.