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The rapid spread of COVID-19 across the world has revealed major gaps in our ability to respond to new virulent pathogens. Rapid, accurate, and easily configurable molecular diagnostic tests are imperative to prevent global spread of new diseases. CRISPR-based diagnostic approaches are proving to be useful as field-deployable solutions. In one basic form of this assay, the CRISPR–Cas12 enzyme complexes with a synthetic guide RNA (gRNA). This complex becomes activated only when it specifically binds to target DNA and cleaves it. The activated complex thereafter nonspecifically cleaves single-stranded DNA reporter probes labeled with a fluorophore−quencher pair.We discovered that electric field gradients can be used to control and accelerate this CRISPR assay by cofocusing Cas12–gRNA, reporters, and target within a microfluidic chip. We achieve an appropriate electric field gradient using a selective ionic focusing technique known as isotachophoresis (ITP) implemented on a microfluidic chip. Unlike previous CRISPR diagnostic assays, we also use ITP for automated purification of target RNA from raw nasopharyngeal swab samples. We here combine this ITP purification with loop-mediated isothermal amplification and the ITP-enhanced CRISPR assay to achieve detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA (from raw sample to result) in about 35 min for both contrived and clinical nasopharyngeal swab samples. This electric field control enables an alternate modality for a suite of microfluidic CRISPR-based diagnostic assays.

One or two monovalent vaccine boosters showed a large decrease in neutralization activity against omicron subvariants. The BA.5-containing bivalent booster improved neutralizing activity against all omicron subvariants.

[...]what to do with test results? Since SARS–CoV-2 is a new virus, there is little evidence to fall back on for test utilization and diagnostic stewardship (1). [...]the true clinical sensitivity of any of these tests is unknown (and is certainly not 100%, as in the hypothetical scenario); a negative test does not therefore negate the possibility that an individual is infected. Testing patients for SARS–CoV-2 helps identify those who are infected, which is useful for individual patient management, as well as for implementation of mitigation strategies to prevent spread in health care facilities and in the community alike (Fig. 1). Alternative strategies for specimen collection, including home collection, should therefore be considered either by a health care provider or patients themselves (or a parent in the case of young children); the use of alternative specimen types, such as oral fluid or nasal swabs (if they are shown to provide results equivalent to those from nasopharyngeal swabs) should also be considered. Spread to health care workers and within health care and long-term-care facilities is a primary consideration for prioritization of testing; testing of patients likely to have SARS–CoV-2 who are in health care facilities or long-term-care facilities, alongside potentially ill workers critical to the pandemic response, including health care workers, public health officials, and other essential leaders, is a priority.

Among samples obtained from persons who had received the mRNA-1273 or BNT162b2 vaccines, neutralizing antibody titers against the B.1.617.1 variant were 6.8 times lower than those against the WA1/2020 variant, and titers against the B.1.617.2 variant were 2.9 times lower than those against WA1/2020.

Most reverse transcription PCR protocols for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) include 2-3 targets for detection. We developed a triplex, real-time reverse transcription PCR for SARS-CoV-2 that maintained clinical performance compared with singleplex assays. This protocol could streamline detection and decrease reagent use during current high SARS-CoV-2 testing demands.

Genetic analysis methods are foundational to advancing personalized medicine, accelerating disease diagnostics, and monitoring the health of organisms and ecosystems. Current nucleic acid technologies such as polymerase chain reaction (PCR) and next-generation sequencing (NGS) rely on sample amplification and can suffer from inhibition. Here, we introduce a label-free genetic screening platform based on high quality (high- Q ) factor silicon nanoantennas functionalized with nucleic acid fragments. Each high- Q nanoantenna exhibits average resonant quality factors of 2,200 in physiological buffer. We quantitatively detect two gene fragments, SARS-CoV-2 envelope (E) and open reading frame 1b (ORF1b), with high-specificity via DNA hybridization. We also demonstrate femtomolar sensitivity in buffer and nanomolar sensitivity in spiked nasopharyngeal eluates within 5 minutes. Nanoantennas are patterned at densities of 160,000 devices per cm 2 , enabling future work on highly-multiplexed detection. Combined with advances in complex sample processing, our work provides a foundation for rapid, compact, and amplification-free molecular assays. The authors present a high quality factor metasurface that enables sensitive and highly-parallelized detection of biomolecules. Amplification-free detection of gene fragments down to femtomolar levels is demonstrated within 5 minutes, for rapid nucleic acid analysis.

Dengue virus (DENV) infection in the presence of reactive, non-neutralizing immunoglobulin G (IgG) (RNNIg) is the greatest risk factor for dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS). Progression to DHF/DSS is attributed to antibody-dependent enhancement (ADE); however, because only a fraction of infections occurring in the presence of RNNIg advance to DHF/DSS, the presence of RNNIg alone cannot account for disease severity. We discovered that DHF/DSS patients respond to infection by producing IgGs with enhanced affinity for the activating Fc receptor FcγRIIIA due to afucosylated Fc glycans and IgG1 subclass. RNNIg enriched for afucosylated IgG1 triggered platelet reduction in vivo and was a significant risk factor for thrombocytopenia. Thus, therapeutics and vaccines restricting production of afucosylated, IgG1 RNNIg during infection may prevent ADE of DENV disease.

Background. Zika virus (ZIKV), chikungunya virus (CHIKV), and dengue virus (DENV) cocirculate in Nicaragua. In this study, we sought to compare the quantified viremia and clinical presentation of patients infected with 1 or more of these viruses. Methods. Acute-phase serum samples from 346 patients with a suspected arboviral illness were tested using a multiplex realtime reverse-transcription polymerase chain reaction for ZIKV, CHIKV, and DENV. Viremia was quantitated for each detected virus, and clinical information from request forms submitted with each sample was recorded. Results. A total of 263 patients tested positive for 1 or more viruses: 192 patients tested positive for a single virus (monoinfections) and 71 patients tested positive for 2 or all 3 viruses (coinfections). Quantifiable viremia was lower in ZIKV infections compared with CHIKV or DENV (mean 4.70 vs 6.42 and 5.84 log10 copies/mL serum, respectively; P < .001 for both comparisons), and for each virus, mean viremia was significantly lower in coinfections than in monoinfections. Compared with patients with CHIKV or DENV, ZIKV patients were more likely to have a rash (P < .001) and less likely to be febrile (P < .05) or require hospitalization (P < .001). Among all patients, hospitalized cases had higher viremia than those who did not require hospitalization (7.1 vs 4.1 log10 copies/mL serum, respectively; P < .001). Conclusions. ZIKV, CHIKV, and DENV result in similar clinical presentations, and coinfections may be relatively common. Our findings illustrate the need for accurate, multiplex diagnostics for patient care and epidemiologic surveillance.