Application of droplet digital PCR in minimal residual disease monitoring of rare fusion transcripts and mutations in haematological malignancies.

Leukaemia of various subtypes are driven by distinct chromosomal rearrangement or genetic abnormalities. The leukaemogenic fusion transcripts or genetic mutations serve as molecular markers for minimal residual disease (MRD) monitoring. The current study evaluated the applicability of several droplet digital PCR assays for the detection of these targets at RNA and DNA levels (atypical BCR::ABL1 e19a2, e23a2ins52, e13a2ins74, rare types of CBFB::MYH11 (G and I), PCM1::JAK2, KMT2A::ELL2, PICALM::MLLT10 fusion transcripts and CEBPA frame-shift and insertion/duplication mutations) with high sensitivity. The analytical performances were assessed by the limit of blanks, limit of detection, limit of quantification and linear regression. Our data demonstrated serial MRD monitoring for patients at molecular level could become "digitalized", which was deemed important to guide clinicians in treatment decision for better patient care.

Evaluation of a Commercial Point-of-Care RT-LAMP Assay for Rapid Detection of SARS-CoV-2.

The goal of this study was to evaluate the performance of a commercial reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay (Detect COVID-19 Test) in the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A total of 202 human respiratory and viral culture specimens were tested retrospectively. The performance of the Detect COVID-19 Test was comparable to that of commercial real-time polymerase chain reaction assays (sensitivity: 93.42%; specificity: 100%), and better than that of the rapid antigen test (sensitivity: 48.00%; specificity: 100%) for specimens with threshold cycle (Ct) values of less than 30. The Beta, Delta, and Omicron variants of concern were successfully detected. With their simplicity of use and good assay sensitivity, point-of-care RT-LAMP assays may be a viable option for SARS-CoV-2 testing at home, or in regions without sophisticated laboratory facilities.

Genomic characteristics and viral load dynamics of a SARS-CoV-2 Omicron BA.2.2 variant from a hospitalized patient treated with molnupiravir.

We sequenced severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genomes from nasal and throat swabs of a hospitalized patient during the fifth wave of coronavirus disease 2019 (COVID-19) pandemic in Hong Kong. Genomic characteristics and viral load dynamics of an Omicron BA.2.2 variant before and after molnupiravir treatment were presented.

Geographical prevalence of SARS-CoV-2 variants, August 2020 to July 2021.

We extracted one-year genomic data (August 2020-July 2021) from GISAID EpiCoV™ database and estimated monthly proportions of 11 SARS-CoV-2 variants in various geographical regions. From continental perspective, Delta VOC predominated in Africa, Asia, Europe, North America and Oceania, with proportions of 67.58-98.31% in July 2021. In South America, proportion of Delta VOC (23.24%) has been approaching the predominant yet diminishing Gamma VOC (56.86%). We further analyzed monthly data on new COVID-19 cases, new deaths, vaccination status and variant proportions of 6 countries. Delta VOC predominated in all countries except Brazil (Gamma VOC) in July 2021. In most occasions, rise and predominance of Alpha, Beta, Gamma, Delta and Zeta variants were accompanied with surges of new cases, especially after the time point of major lineage interchange. The ascending phases of new cases lasted for 1-5 months with 1.69- to 40.63-fold peak growth, whereas new death tolls varied with regional vaccination status. Our data suggested surges of COVID-19 cases might be predicted from variant surveillance data. Despite vaccine breakthroughs by Delta VOC, death tolls were more stable in countries with better immunization coverage. Another takeaway is the urgent need to improve vaccine efficacy against Delta and emerging variants.