Astrocytes Assemble Thalamocortical Synapses by Bridging NRX1α and NL1 via Hevin.

Proper establishment of synapses is critical for constructing functional circuits. Interactions between presynaptic neurexins and postsynaptic neuroligins coordinate the formation of synaptic adhesions. An isoform code determines the direct interactions of neurexins and neuroligins across the synapse. However, whether extracellular linker proteins can expand such a code is unknown. Using a combination of in vitro and in vivo approaches, we found that hevin, an astrocyte-secreted synaptogenic protein, assembles glutamatergic synapses by bridging neurexin-1alpha and neuroligin-1B, two isoforms that do not interact with each other. Bridging of neurexin-1alpha and neuroligin-1B via hevin is critical for the formation and plasticity of thalamocortical connections in the developing visual cortex. These results show that astrocytes promote the formation of synapses by modulating neurexin/neuroligin adhesions through hevin secretion. Our findings also provide an important mechanistic insight into how mutations in these genes may lead to circuit dysfunction in diseases such as autism.

Pathogenicity of Highly Pathogenic Avian Influenza A(H5N1) Viruses Isolated from Cats in Mice and Ferrets, South Korea, 2023.

The prevalence of highly pathogenic avian influenza (HPAI) A(H5N1) viruses has increased in wild birds and poultry worldwide, and concomitant outbreaks in mammals have occurred. During 2023, outbreaks of HPAI H5N1 virus infections were reported in cats in South Korea. The H5N1 clade 2.3.4.4b viruses isolated from 2 cats harbored mutations in the polymerase basic protein 2 gene encoding single amino acid substitutions E627K or D701N, which are associated with virus adaptation in mammals. Hence, we analyzed the pathogenicity and transmission of the cat-derived H5N1 viruses in other mammals. Both isolates caused fatal infections in mice and ferrets. We observed contact infections between ferrets, confirming the viruses had high pathogenicity and transmission in mammals. Most HPAI H5N1 virus infections in humans have occurred through direct contact with poultry or a contaminated environment. Therefore, One Health surveillance of mammals, wild birds, and poultry is needed to prevent potential zoonotic threats.

Efficacy of transdermal buprenorphine patch for managing withdrawal symptoms in patients with cancer physically dependent on prescription opioids.

BACKGROUND: The physical dependence on prescription opioids among cancer survivors remains an under-investigated area, with a scarcity of well-designed prospective studies. METHODS: This single-arm, phase-2 clinical trial in Korea assessed the efficacy and safety of a transdermal buprenorphine patch (TBP) in managing physical dependence on prescription opioids in cancer survivors, as confirmed through the DSM-5 criteria or psychiatric consultation for opioid withdrawal. This study involved a 4-phase treatment protocol of screening, induction/stabilization, discontinuation, and monitoring. The primary outcome was the rate of successful opioid discontinuation, as measured by a negative urine-drug screening at 8 weeks. Key secondary outcomes included the resumption of prescribed opioids, changes in both the Clinical Opioid Withdrawal Scale (COWS) and morphine equivalent daily dose (MEDD), and assessments related to the psychological and physiological aspects of dependence and safety. RESULTS: Thirty-one participants were enrolled. In the intention-to-treat population, the success rate of opioid discontinuation was 58%, with only 2 participants experiencing a resumption of prescribed opioids. Significant reductions were observed in MEDD, which decreased from 98 to 26 mg/day (P < .001), and COWS scores, which decreased from 5.5 to 2.8 (P < .001). Desire to use opioids reduced from 7.0 to 3.0 on a 10-point numeric rating scale (P < .001). Toxicities related to TBP were mild and manageable, without severe precipitated withdrawal symptoms. CONCLUSION: TBP may be considered as an alternative therapeutic option in cancer survivors physically dependent on prescription opioids, especially where sublingual formulations are unavailable.

Efficacy of cisplatin-gemcitabine-durvalumab in patients with advanced biliary tract cancer experiencing early vs late disease relapse after surgery: a large real-life worldwide population.

BACKGROUND: In the TOPAZ-1, patients with biliary tract cancers (BTC) and recurrence within 6 months after surgery were excluded, even if this event is frequently observed in clinical practice. Our study aimed to assess if the efficacy of cisplatin-gemcitabine-durvalumab (CGD) in this population is comparable to that reported in the phase 3 trial. METHODS: The study cohort included patients with BTC who underwent surgery on the primary tumor, experienced disease recurrence occurring ≤6 months or >6 months after surgery or after the end of adjuvant therapy and started CGD. The primary objectives were overall survival (OS) and progression free survival (PFS). RESULTS: A total of 178 patients were enrolled. No significant differences were observed between early and late relapse groups in OS (23.4 months vs not reached; HR 1.26; 95% CI, 0.67-2.37; P = .45) and PFS [7.0 months vs 9.8 months; HR 1.3(95% CI, 0.9-2.1) P = .13]. Overall response rate and disease control rate (P = .33 and P = .62) were comparable between the 2 groups, as the overall safety profile. In addition, we compared survival outcomes between the selected population and a historical cohort of patients with BTC treated with cisplatin-gemcitabine (CG) and found that despite the absence of statistical significance, CGD showed an outcome trend compared with CG regardless of the time of recurrence after surgery or adjuvant chemotherapy [(CG ≤ 6 vs CGD ≤ 6 months: HR 0.59, 95%CI, 0.35-1.01, P = .05; HR 0.70; 95%CI, 0.46-1.06, P = .09, OS and PFS, respectively) and (CG > 6 vs. CGD > 6 months: HR 0.50; 95%CI, 0.29-0.88, P = 0.0165; HR 0.54; 95%CI, 0.35-0.84, P = .0068, OS and PFS, respectively)]. CONCLUSION: Our analysis suggests that CGD retains its efficacy independently of the timing of relapse after surgery or completion of adjuvant treatment in patients with advanced BTC.

The PFC-LH-VTA pathway contributes to social deficits in IRSp53-mutant mice.

Dopamine (DA) neurons in the ventral tegmental area (VTA) promote social brain functions by releasing DA onto nucleus accumbens neurons, but it remains unclear how VTA neurons communicate with cortical neurons. Here, we report that the medial prefrontal cortex (mPFC)-lateral hypothalamus (LH)-VTA pathway contributes to social deficits in mice with IRSp53 deletion restricted to cortical excitatory neurons (Emx1-Cre;Irsp53fl/fl mice). LH-projecting mutant mPFC neurons display abnormally increased excitability involving decreased potassium channel gene expression, leading to excessive excitatory synaptic input to LH-GABA neurons. A circuit-specific IRSp53 deletion in LH-projecting mPFC neurons also increases neuronal excitability and induces social deficits. LH-GABA neurons with excessive mPFC excitatory synaptic input show a compensatory decrease in excitability, weakening the inhibitory LHGABA-VTAGABA pathway and subsequently over-activating VTA-GABA neurons and over-inhibiting VTA-DA neurons. Accordingly, optogenetic activation of the LHGABA-VTAGABA pathway improves social deficits in Emx1-Cre;Irsp53fl/fl mice. Therefore, the mPFC-LHGABA-VTAGABA-VTADA pathway contributes to the social deficits in Emx1-Cre;Irsp53fl/fl mice.

Changes in the intrinsic severity of severe acute respiratory syndrome coronavirus 2 according to the emerging variant: a nationwide study from February 2020 to June 2022, including comparison with vaccinated populations.

BACKGROUND: As the population acquires immunity through vaccination and natural infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), understanding the intrinsic severity of coronavirus disease (COVID-19) is becoming challenging. We aimed to evaluate the intrinsic severity regarding circulating variants of SARS-CoV-2 and to compare this between vaccinated and unvaccinated individuals. METHODS: With unvaccinated and initially infected confirmed cases of COVID-19, we estimated the case severity rate (CSR); case fatality rate (CFR); and mortality rate (MR), including severe/critical cases and deaths, stratified by age and compared by vaccination status according to the period regarding the variants of COVID-19 and vaccination. The overall rate was directly standardized with age. RESULTS: The age-standardized CSRs (aCSRs) of the unvaccinated group were 2.12%, 5.51%, and 0.94% in the pre-delta, delta, and omicron period, respectively, and the age-standardized CFRs (aCFRs) were 0.60%, 2.49%, and 0.63% in each period, respectively. The complete vaccination group had lower severity than the unvaccinated group over the entire period showing under 1% for the aCSR and 0.5% for the aCFR. The age-standardized MR of the unvaccinated group was 448 per million people per month people in the omicron period, which was 11 times higher than that of the vaccinated group. In terms of age groups, the CSR and CFR sharply increased with age from the 60 s and showed lower risk reduction in the 80 s when the period changed to the omicron period. CONCLUSIONS: The intrinsic severity of COVID-19 was the highest in the delta period, with over 5% for the aCSR, whereas the completely vaccinated group maintained below 1%. This implies that when the population is vaccinated, the impact of COVID-19 will be limited, even if a new mutation appears. Moreover, considering the decreasing intrinsic severity, the response to COVID-19 should prioritize older individuals at a higher risk of severe disease.

Suppression of a transcriptional regulator, HexA, is essential for triggering the bacterial virulence of the entomopathogen, Xenorhabdus hominickii.

A nematode-symbiotic bacterium, Xenorhabdus hominickii, exhibits two distinct lifestyles. Upon infection of its host nematode into a target insect, X. hominickii is released into the insect hemocoel and becomes pathogenic. This study examines the critical transformation in bacterial life forms concerning the activity of a transcriptional regulator, HexA. When X. hominickii was cultured in tryptic soy broth, HexA was expressed during the stationary phase of bacterial growth. Conversely, HexA was expressed in the early growth stage within the insect host, Spodoptera exigua, when infected with X. hominickii. The transient expression of HexA was succeeded by the expression of another transcriptional regulator, Lrp, which led to the production of bacterial virulent factors. Expression of HexA was manipulated by replacing its promoter with an inducible promoter controlled by the inducer, l-arabinose. In the absence of the inducer, the mutant bacteria expressed HexA at a low level, resulting in a bacterial culture broth that was more effective at suppressing insect immune responses than the wild type. When the inducer was added, HexA was expressed at high levels, rendering the culture broth ineffective in immunosuppression. Interestingly, expression of HexA inhibited the expression of another transcriptional regulator, Lrp, which in turn induced the expression of a non-ribosomal peptide synthetase, gxpS, leading to the production of an immunosuppressive metabolite, GXP. Suppression of HexA expression in mutant bacteria augmented GXP levels in secondary metabolites. This indicates that infection of X. hominickii into the insect host represses HexA expression and upregulates Lrp expression, leading to GXP production. The GXP metabolites inhibit insect immunity, thus protecting the bacteria-nematode complex. Therefore, the suppression of HexA expression in the insect hemocoel is crucial for the bacteria's transition from a symbiotic to a pathogenic life form.

A Surface Acoustic Wave-Based PM 1.0 Fine Dust Detection System Using Full Digital Time-Interleaved Counters.

This paper proposed a fine dust detection system using time-interleaved counters in which surface acoustic wave (SAW) sensors changed the resonance point characteristic. When fine dust was applied to the SAW sensor, the resonance point decreased. The SAW oscillator made of the SAW sensor and radio frequency (RF) amplifier generated an oscillation frequency that was the same as the resonance frequency. The oscillation frequency was transferred to digital data by a 20-bit asynchronous counter. This system has two channels: a sensing channel and a reference channel. Each channel has a SAW oscillator and a 20-bit asynchronous counter. The difference of the two channel counter results is the frequency difference. Through this, it is possible to know whether fine dust adheres to the SAW sensor. The proposed circuit achieved 0.95 ppm frequency resolution when it was operated at a frequency of 460 MHz. This circuit was implemented in a TSMC 130 nm CMOS process.

Efficacy of skin rejuvenation with a fractional 1927-nm thulium laser alone or combined with a chemical peel: a controlled histopathological preliminary study in a mouse model.

Many patients demand minimally invasive treatments for skin rejuvenation, such as nonablative laser and superficial chemical peels. Combination therapy yet has not been studied histopathologically. The purpose of this study is to assess the histopathological efficacy of a 1927-nm thulium laser-assisted salicylic acid (SA) peel in skin rejuvenation. A six-segment table was drawn on the shaved back of C57BL/6 mouse. All segments were irradiated with the thulium laser-different tips and passes were used for specific segments. A 30% SA peel was then applied to the right-hand segments. After treatment, the skin samples were collected from each segment and examined for dermal thickness, collagen density, and melanin content. Greater thickness was seen in the combination therapy group compared with the laser alone group and in those segments receiving more passes with larger beam-sized tip. Collagen density increased in all treated skin segments, irrespective of the group. No adverse events were noted in the treated areas. The sample size was small and mouse skin has histological differences with human skin. The combination of a thulium laser and 30% SA peel has a synergistic effect on dermal thickness, so that can be suggested as a novel skin rejuvenation technique.

Comparative Computational Analysis of Spike Protein Structural Stability in SARS-CoV-2 Omicron Subvariants.

The continuous emergence of new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with multiple spike (S) protein mutations pose serious threats to current coronavirus disease 2019 (COVID-19) therapies. A comprehensive understanding of the structural stability of SARS-CoV-2 variants is vital for the development of effective therapeutic strategies as it can offer valuable insights into their potential impact on viral infectivity. S protein mediates a virus' attachment to host cells by binding to angiotensin-converting enzyme 2 (ACE2) through its receptor-binding domain (RBD), and mutations in this protein can affect its stability and binding affinity. We analyzed S protein structural stability in various Omicron subvariants computationally. Notably, the S protein sequences analyzed in this work were obtained directly from our own sample collection. We evaluated the binding free energy between S protein and ACE2 in several complex forms. Additionally, we measured distances between the RBD of each chain in S protein to analyze conformational changes. Unlike most of the prior studies, we analyzed full-length S protein-ACE2 complexes instead of only RBD-ACE2 complexes. Omicron subvariants including BA.1, BA.2, BA.2.12.1, BA.4/BA.5, BA.2.75, BA.2.75_K147E, BA.4.6 and BA.4.6_N658S showed enhanced stability compared to wild type, potentially due to distinct S protein mutations. Among them, BA.2.75 and BA.4.6_N658S exhibited the highest and lowest level of stability, respectively.

Serial Intervals and Household Transmission of SARS-CoV-2 Omicron Variant, South Korea, 2021.

To clarify transmissibility of the severe acute respiratory syndrome coronavirus 2 Omicron variant, we determined serial intervals and secondary attack rates among household contacts in South Korea. Mean serial interval for 12 transmission pairs was 2.9 days, and secondary attack rate among 25 households was 50.0%, raising concern about a rapid surge in cases.

SARS-CoV-2 B.1.619 and B.1.620 Lineages, South Korea, 2021.

We report the rapid emergence of severe acute respiratory syndrome coronavirus 2 lineages B.1.619 and B.1.620 in South Korea. The surge in frequency in a relatively short time emphasizes the need for ongoing monitoring for new lineages to track potential increases in transmissibility and disease severity and reductions in vaccine efficacy.

Community Transmission of SARS-CoV-2 Omicron Variant, South Korea, 2021.

In South Korea, a November 2021 outbreak caused by severe acute respiratory syndrome coronavirus 2 Omicron variant originated from 1 person with an imported case and spread to households, kindergartens, workplaces, restaurants, and hospitals, resulting in 11 clusters within 3 weeks. An epidemiologic curve indicated rapid community transmission of the Omicron variant.

Long-term outcomes in patients with advanced and/or metastatic non-small cell lung cancer who completed 2 years of immune checkpoint inhibitors or achieved a durable response after discontinuation without disease progression: Multicenter, real-world data (KCSG LU20-11).

BACKGROUND: Immune checkpoint inhibitors (ICIs) have shown significant improvements in patients with advanced non-small cell lung cancer (NSCLC). One of the major issues with ICIs is determining the optimal treatment duration. METHODS: This multicenter, retrospective study analyzed clinical outcomes in patients with NSCLC who completed 2 years of ICI therapy or were treated for more than 6 months and then discontinued ICIs without disease progression at 11 medical centers in Korea between August 2017 and December 2020. RESULTS: Ninety-six patients who completed 2 years of ICIs were reviewed. The median durations of treatment and follow-up were 24.0 and 33.9 months, respectively. The objective response rate (ORR) was 85.4%. The median progression-free survival (PFS) and overall survival (OS) periods were not reached. After completion, the PFS and OS rates were 81.1% and 96.4%, respectively, at 12 months. Forty-three patients were identified who discontinued ICIs without disease progression: 26 (60.5%) for adverse events and 17 (39.5%) for other causes. The median durations of treatment and follow-up were 10.5 and 21.2 months, respectively. The ORR was 90.7%. The median PFS and OS periods were not reached. After discontinuation, the PFS and OS rates were 71.0% and 90.0%, respectively, at 12 months. CONCLUSIONS: A significantly high proportion of patients who completed 2 years of ICI therapy continued to experience long-term PFS. Even if ICIs are discontinued after 6 months in patients without disease progression, they may achieve a durable response and facilitate long-term survival. LAY SUMMARY: The optimal treatment duration for immune checkpoint inhibitors (ICIs) remains to be determined. This study reports the long-term outcomes of patients with non-small cell lung cancer who completed 2 years of ICI therapy or achieved a durable response after the discontinuation of ICIs without disease progression in real-world practice. A significantly high proportion of patients who completed 2 years of ICIs continued to experience long-term progression-free survival. In addition, even if ICIs are discontinued after 6 months in patients without disease progression, they may achieve a durable response and facilitate long-term survival.

Combined treatment with anti-HER2/neu and anti-4-1BB monoclonal antibodies induces a synergistic antitumor effect but requires dose optimization to maintain immune memory for protection from lethal rechallenge.

Human epidermal growth factor receptor type 2 (HER2)-positive breast cancer that is treated with anti-HER2/neu monoclonal antibody (mAb) is not free from late recurrences. Addition of anti-4-1BB mAb to anti-HER2/neu mAb has been demonstrated to strengthen the cytotoxic antitumor response. Our study expands on this by revealing the influence of anti-4-1BB mAb addition on the immune memory of anti-HER2/neu mAb. We designed murine breast cancer models by implanting TUBO and TUBO-P2J cell lines in mice, which were then treated with anti-HER2/neu and/or anti-4-1BB mAb. After complete surgical and/or chemical regression of the tumor, the mice were rechallenged with a second injection of cancer cells. Notably, anti-HER2/neu and anti-4-1BB mAb combination therapy had a synergistic antitumor effect at the initial treatment. However, the combination therapy did not evoke immune memory, allowing the tumors to thrive at rechallenge with reduced CD44+ expression in CD8+ T cells. Immune memory was also impaired when anti-4-1BB mAb was administered to naive CD8+ T cells but was sustained when this was administered to activated CD8+ T cells. In an attempt to resist the loss of immune memory, we controlled the dose of anti-4-1BB mAb to optimize the stimulation of activated CD8+ T cells. Immune memory was achieved with the dose regulation of anti-4-1BB mAb to 1 mg/kg in our model. Our study demonstrates the importance in understanding the adaptive immune mechanism of anti-HER2/neu and anti-4-1BB mAb combination therapy and suggests a dose optimization strategy is necessary to ensure development of successful immune memory.

A mosquito juvenile hormone binding protein (mJHBP) regulates the activation of innate immune defenses and hemocyte development.

Insects rely on the innate immune system for defense against pathogens, some aspects of which are under hormonal control. Here we provide direct experimental evidence showing that the juvenile hormone-binding protein (mJHBP) of Aedes aegypti is required for the regulation of innate immune responses and the development of mosquito blood cells (hemocytes). Using an mJHBP-deficient mosquito line generated by means of CRISPR-Cas9 gene editing technology we uncovered a mutant phenotype characterized by immunosuppression at the humoral and cellular levels, which profoundly affected susceptibility to bacterial infection. Bacteria-challenged mosquitoes exhibited significantly higher levels of septicemia and mortality relative to the wild type (WT) strain, delayed expression of antimicrobial peptides (AMPs), severe developmental dysregulation of embryonic and larval hemocytes (reduction in the total number of hemocytes) and increased differentiation of the granulocyte lineage. Interestingly, injection of recombinant wild type mJHBP protein into adult females three-days before infection was sufficient to restore normal immune function. Similarly, injection of mJHBP into fourth-instar larvae fully restored normal larval/pupal hemocyte populations in emerging adults. More importantly, the recovery of normal immuno-activation and hemocyte development requires the capability of mJHBP to bind JH III. These results strongly suggest that JH III functions in mosquito immunity and hemocyte development in a manner that is perhaps independent of canonical JH signaling, given the lack of developmental and reproductive abnormalities. Because of the prominent role of hemocytes as regulators of mosquito immunity, this novel discovery may have broader implications for the understanding of vector endocrinology, hemocyte development, vector competence and disease transmission.

Genomic evidence of SARS-CoV-2 reinfection in the Republic of Korea.

As the coronavirus disease 2019 (COVID-19) pandemic continues, reinfection is likely to become increasingly common. However, confirming COVID-19 reinfection is difficult because it requires whole-genome sequencing of both infections to identify the degrees of genetic differences. Since the first reported case of reinfection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the Republic of Korea in April 2020, four additional cases were classified as suspected reinfection cases. We performed whole-genome sequencing of viral RNA extracted from swabs obtained at the initial infection and reinfection stages of these four suspected cases. The interval between initial infection and reinfection of all four suspected cases was more than 3 months. All four patients were young (10-29 years), and they displayed mild symptoms or were asymptomatic during the initial infection and reinfection episodes. The analysis of genome sequences combined with the epidemiological results revealed that only two of the four cases were confirmed as reinfection, and both were reinfected with the Epsilon variant. Due to the prolonged COVID-19 pandemic, the possibility of reinfections with SARS-CoV-2 variants is increasing, as reported in our study. Therefore, continuous monitoring of cases is necessary.

Identification of the fate and regenerative mechanism of zebrafish melanocyte progenitor cells and melanocytes after laser-induced pigment ablation.

BACKGROUND AND OBJECTIVES: Lasers are known to be the most effective treatment modality for pigmentary skin diseases. However, melanocytes and melanin pigment often recur or leave post-inflammatory hyperpigmentation after the laser procedure. Studies have reported on the role of progenitor cells in pigment cell regeneration, which can be constantly replenished through mitosis. However, the response of unpigmented melanocyte progenitor cells to laser treatment is poorly understood. In this study, we used adult zebrafish skin as the melanocyte regenerative system and examined the response of melanocyte progenitor cells to laser photothermolysis. MATERIALS AND METHODS: The two groups of adult zebrafish were irradiated with 1064 nm wavelength laser system of Q-switched neodymium:yttrium-aluminum-garnet (Nd:YAG) laser with 0.3 or 0.7 J·cm-2 . We compared the regeneration of pigment at different energy levels by measuring new melanocyte counts and pigment area. We traced and quantitatively compared the melanocyte lineage cells by immunohistochemical staining using specific markers such as sox10, mitfa, and dct during the regeneration process. Three repetitive laser ablations were also held to test the postinflammatory hyperpigmentation. RESULTS: After the laser ablation of melanocytes, most of the new melanocytes appeared between Days 5 and 10. In high-energy irradiation of 0.7 J·cm-2 , the unpigmented mitfa-expressing cells showed significant decrease (p < 0.05) and showed delay in the differentiation process of melanocyte lineage cells. After repeated laser irradiation, hyperpigmentation did not appear and the final recovery ratio of the pigmented area was 87.5% and 75.3% at the 0.3 and 0.7 J·cm-2 energy levels, respectively. CONCLUSION: We suggest that laser treatment overcoming the recurrence should be planned based on the adequate energy level targeting the melanocyte progenitor cells. High-energy irradiation may induce apoptosis of progenitor cells and delay their process of differentiation. Short-term repetitive sessions of laser therapy can reduce the pigmentation in the long-term observation.

Importation and Transmission of SARS-CoV-2 B.1.1.529 (Omicron) Variant of Concern in Korea, November 2021.

In November 2021, 14 international travel-related severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) B.1.1.529 (omicron) variant of concern (VOC) patients were detected in South Korea. Epidemiologic investigation revealed community transmission of the omicron VOC. A total of 80 SARS-CoV-2 omicron VOC-positive patients were identified until December 10, 2021 and 66 of them reported no relation to the international travel. There may be more transmissions with this VOC in Korea than reported.

Nucleic Acid Testing of SARS-CoV-2.

The coronavirus disease 2019 (COVID-19) has caused a large global outbreak. It is accordingly important to develop accurate and rapid diagnostic methods. The polymerase chain reaction (PCR)-based method including reverse transcription-polymerase chain reaction (RT-PCR) is the most widely used assay for the detection of SARS-CoV-2 RNA. Along with the RT-PCR method, digital PCR has emerged as a powerful tool to quantify nucleic acid of the virus with high accuracy and sensitivity. Non-PCR based techniques such as reverse transcription loop-mediated isothermal amplification (RT-LAMP) and reverse transcription recombinase polymerase amplification (RT-RPA) are considered to be rapid and simple nucleic acid detection methods and were reviewed in this paper. Non-conventional molecular diagnostic methods including next-generation sequencing (NGS), CRISPR-based assays and nanotechnology are improving the accuracy and sensitivity of COVID-19 diagnosis. In this review, we also focus on standardization of SARS-CoV-2 nucleic acid testing and the activity of the National Metrology Institutes (NMIs) and highlight resources such as reference materials (RM) that provide the values of specified properties. Finally, we summarize the useful resources for convenient COVID-19 molecular diagnostics.