Transmission Patterns of Co-Circulation of Omicron Sub-Lineages in Hong Kong SAR, China, a City with Rigorous Social Distancing Measures, in 2022.

OBJECTIVE: This study aimed to characterize the changing landscape of circulating SARS-CoV-2 lineages in the local community of Hong Kong throughout 2022. We examined how adjustments to quarantine arrangements influenced the transmission pattern of Omicron variants in a city with relatively rigorous social distancing measures at that time. METHODS: In 2022, a total of 4684 local SARS-CoV-2 genomes were sequenced using the Oxford Nanopore GridION sequencer. SARS-CoV-2 consensus genomes were generated by MAFFT, and the maximum likelihood phylogeny of these genomes was determined using IQ-TREE. The dynamic changes in lineages were depicted in a time tree created by Nextstrain. Statistical analysis was conducted to assess the correlation between changes in the number of lineages and adjustments to quarantine arrangements. RESULTS: By the end of 2022, a total of 83 SARS-CoV-2 lineages were identified in the community. The increase in the number of new lineages was significantly associated with the relaxation of quarantine arrangements (One-way ANOVA, F(5, 47) = 18.233, p < 0.001)). Over time, Omicron BA.5 sub-lineages replaced BA.2.2 and became the predominant Omicron variants in Hong Kong. The influx of new lineages reshaped the dynamics of Omicron variants in the community without fluctuating the death rate and hospitalization rate (One-way ANOVA, F(5, 47) = 2.037, p = 0.091). CONCLUSION: This study revealed that even with an extended mandatory quarantine period for incoming travelers, it may not be feasible to completely prevent the introduction and subsequent community spread of highly contagious Omicron variants. Ongoing molecular surveillance of COVID-19 remains essential to monitor the emergence of new recombinant variants.

Probable airborne transmission of Burkholderia pseudomallei causing an urban outbreak of melioidosis during typhoon season in Hong Kong, China.

Between January 2015 and October 2022, 38 patients with culture-confirmed melioidosis were identified in the Kowloon West (KW) Region, Hong Kong. Notably, 30 of them were clustered in the Sham Shui Po (SSP) district, which covers an estimated area of 2.5 km2. Between August and October 2022, 18 patients were identified in this district after heavy rainfall and typhoons. The sudden upsurge in cases prompted an environmental investigation, which involved collecting 20 air samples and 72 soil samples from residential areas near the patients. A viable isolate of Burkholderia pseudomallei was obtained from an air sample collected at a building site five days after a typhoon. B. pseudomallei DNA was also detected in 21 soil samples collected from the building site and adjacent gardening areas using full-length 16S rRNA gene sequencing, suggesting that B. psuedomallei is widely distributed in the soil environment surrounding the district. Core genome-multilocus sequence typing showed that the air sample isolate was phylogenetically clustered with the outbreak isolates in KW Region. Multispectral satellite imagery revealed a continuous reduction in vegetation region in SSP district by 162,255 m2 from 2016 to 2022, supporting the hypothesis of inhalation of aerosols from the contaminated soil as the transmission route of melioidosis during extreme weather events. This is because the bacteria in unvegetated soil are more easily spread by winds. In consistent with inhalational melioidosis, 24 (63.2%) patients had pneumonia. Clinicians should be aware of melioidosis during typhoon season and initiate appropriate investigation and treatment for patients with compatible symptoms.

Effect of Antiviral Treatment on Hepatitis B Virus Integration and Hepatocyte Clonal Expansion.

BACKGROUND: This study investigated the effect of nucleos(t)ide analogue (NUC) treatment on hepatitis B virus (HBV) DNA integration and hepatocyte clonal expansion, both of which are implicated in hepatocellular carcinoma (HCC) in chronic hepatitis B. METHODS: Twenty-eight patients receiving NUCs (11 lamivudine, 7 telbivudine, 10 entecavir) were included. All had liver biopsies at baseline and year 1, and 7 had a third biopsy at year 10. HBV DNA integration and hepatocyte clone size were assessed by inverse polymerase chain reaction. RESULTS: All patients had detectable HBV integration at baseline, with a median integration frequency of 1.01 × 109 per liver and hepatocyte clone size of 2.41 × 105. Neither integration frequency nor hepatocyte clone size correlated with age and HBV virologic parameters. After 1 year of treatment, HBV integration was still detectable in all patients, with a median of 5.74 × 108 integration per liver (0.22 log reduction; P = .008) and hepatocyte clone size of 1.22 × 105 (0.40 log reduction; P = .002). HBV integration remained detectable at year 10 of treatment, with a median integration frequency of 4.84 × 107 integration per liver (0.93 log reduction from baseline) and hepatocyte clone size of 2.55 × 104 (1.02 log reduction from baseline). From baseline through year 1 to year 10, there was a decreasing trend in both integration frequency and hepatocyte clone size (P = .066 and.018, respectively). CONCLUSIONS: NUCs reduced both HBV DNA integration and hepatocyte clonal expansion, suggesting another alternative pathway besides direct viral suppression to reduce HCC risk. Our findings supported the notion for a long-term NUC treatment to prevent HCC.

Hepatitis B virus pre-genomic RNA and hepatitis B core-related antigen reductions at week 4 predict favourable hepatitis B surface antigen response upon long-term nucleos(t)ide analogue in chronic hepatitis B.

BACKGROUND/AIMS: We investigated the dynamics of serum HBV pre-genomic RNA (pgRNA) and hepatitis B core-related antigen (HBcrAg) in patients receiving nucleos(t)ide analogues (NAs) and their predictability for favourable suppression of serum hepatitis B surface antigen (HBsAg). METHODS: Serum viral biomarkers were measured at baseline, weeks 4, 12, 24, 36, and 48 of treatment. Patients were followed up thereafter and serum HBsAg level was measured at end of follow-up (EOFU). Favourable HBsAg response (FHR) was defined as ≤100 IU/mL or HBsAg seroclearance upon EOFU. RESULTS: Twenty-eight hepatitis B e antigen (HBeAg)-positive and 36 HBeAg-negative patients (median, 38.2 years old; 71.9% male) were recruited with median follow-up duration of 17.1 years (interquartile range, 12.8-18.2). For the entire cohort, 22/64 (34.4%) achieved FHR. For HBeAg-positive patients, serum HBV pgRNA decline at week 4 was significantly greater for patients with FHR compared to non-FHR (5.49 vs. 4.32 log copies/mL, respectively; P=0.016). The area under the receiver-operating-characteristic curve (AUROC) for week 4 HBV pgRNA reduction to predict FHR in HBeAg-positive patients was 0.825 (95% confidence interval [CI], 0.661-0.989). For HBeAg-negative patients, instead of increase in serum HBcrAg in non-FHR patients, FHR patients had median reduction in HBcrAg at week 4 (increment of 1.75 vs. reduction of 2.98 log U/mL; P=0.023). The AUROC for week 4 change of HBcrAg to predict FHR in HBeAg-negative patients was 0.789 (95% CI, 0.596-0.982). CONCLUSION: Early on-treatment changes of serum HBV pgRNA and HBcrAg at 4 weeks predict HBsAg seroclearance or ≤100 IU/mL in NA-treated CHB patients upon long-term FU.

Unconventional tonicity-regulated nuclear trafficking of NFAT5 mediated by KPNB1, XPOT and RUVBL2.

NFAT5 is the only known mammalian tonicity-responsive transcription factor with an essential role in cellular adaptation to hypertonic stress. It is also implicated in diverse physiological and pathological processes. NFAT5 activity is tightly regulated by extracellular tonicity, but the underlying mechanisms remain elusive. Here, we demonstrate that NFAT5 enters the nucleus via the nuclear pore complex. We found that NFAT5 utilizes a unique nuclear localization signal (NFAT5-NLS) for nuclear import. siRNA screening revealed that only karyopherin ß1 (KPNB1), but not karyopherin α, is responsible for the nuclear import of NFAT5 via direct interaction with the NFAT5-NLS. Proteomics analysis and siRNA screening further revealed that nuclear export of NFAT5 under hypotonicity is driven by exportin-T (XPOT), where the process requires RuvB-like AAA-type ATPase 2 (RUVBL2) as an indispensable chaperone. Our findings have identified an unconventional tonicity-dependent nucleocytoplasmic trafficking pathway for NFAT5 that represents a critical step in orchestrating rapid cellular adaptation to change in extracellular tonicity. These findings offer an opportunity for the development of novel NFAT5 targeting strategies that are potentially useful for the treatment of diseases associated with NFAT5 dysregulation.

Role of serum HBV RNA and hepatitis B surface antigen levels in identifying Asian patients with chronic hepatitis B suitable for entecavir cessation.

BACKGROUND: Treatment cessation in chronic HBV infection may be durable in certain patient subgroups before hepatitis B surface antigen (HBsAg) seroclearance. The role of serum HBV RNA in determining treatment cessation suitability has not been well-investigated. METHODS: Nucleos(t)ide analogue (NUC) treatment was discontinued in non-cirrhotic patients with chronic HBV with serum HBsAg <200 IU/mL and fulfilling internationally recommended criteria for treatment cessation. Patients were monitored till 48 weeks with baseline and serial measurements of serum HBsAg, HBV RNA and hepatitis B core-related antigen. NUCs were resumed when HBV DNA reaches >2000 IU/mL regardless of alanine aminotransferase (ALT) levels. RESULTS: 114 entecavir-treated patients (median age 58.4 years, median serum HBsAg 54.4 IU/mL) with median treatment duration of 6.7 years were recruited. The 48-week cumulative rate of HBV DNA >2000 IU/mL was 58.1%. End-of-treatment serum HBV RNA and off-treatment serial HBV RNA were both independently associated with HBV DNA >2000 IU/mL (HR 2.959, 95% CI 1.776 to 4.926, p<0.001; HR 2.278, 95% CI 1.151 to 4.525, p=0.018, respectively). Patients with HBV RNA ≥44.6 U/mL had a cumulative 48-week rate of 93.2%, while combining HBV RNA undetectability and HBsAg <10 IU/mL had a cumulative 48-week rate of 9.1%. 24 patients (38.7%) developed off-treatment ALT elevation, highest peak ALT was 1515 U/L. 8 patients (median serum HBsAg 2.6 IU/mL) developed HBsAg seroclearance. CONCLUSION: Serum HBV RNA measurement is essential for deciding on entecavir cessation in patients with chronic HBV, especially with low HBsAg levels. Patients can be stratified on their risk of off-treatment relapse based on both viral determinants. TRIAL REGISTRATION NUMBER: NCT02738554.