Predictive Value of Various Atypical Cells for the Detection of Human Papillomavirus in Cervical Smears.

It is thought that numerous genotypes of human papillomavirus (HPV) are associated with various atypical cells, such as multinucleated cells, koilocytes, binucleated cells, parakeratotic cells, and giant cells, in the cervix. We previously showed the specificity of HPV genotypes for koilocytes and multinucleated cells. Therefore, in this study, we analyzed the association among HPV genotypes and binucleated cells, parakeratotic cells, and giant cells in Papanicolaou (Pap) smears. We detected HPV genotypes and atypical cells in 651 cases of liquid-based cytology with an abnormal Pap smear. The HPV genotypes associated with atypical cells were evaluated using stepwise logistic regression with backward elimination and a likelihood ratio test for model construction. Polymerase chain reaction was used to determine the HPV genotypes in whole liquid-based cytology samples and microdissected cell samples from Pap smear slides. Binucleated cells were significantly associated with HPV genotype 42. Moreover, parakeratotic cells were significantly associated with certain HPV genotypes, such as HPV40. However, it was difficult to detect specific HPV genotypes by the manual microdissection-polymerase chain reaction method despite the presence of binucleated cells and parakeratotic cells. Thus, the presence of binucleated cells, parakeratotic cells, and giant cells in Pap smears may not be predictive of cervical lesions above low-grade squamous intraepithelial lesions or infection with highly carcinogenic HPV genotypes.

Cytological features of human papillomavirus-infected immature squamous metaplastic cells from cervical intraepithelial neoplasia grade 2.

In reflex cytology, the presence of prominent nucleoli in immature metaplastic squamous cells (IM) may be underdiagnosed due to variations in interpretation. The aim of this study is to identify human papillomaviruses (HPVs) that infect IM clusters in cervical intraepithelial neoplasia 2 (CIN2) on Papanicolaou (Pap) smears to determine the cytological features of lesion-derived cells. Thirty-two patients with a simultaneous diagnosis of CIN2 on biopsy and high-grade squamous intraepithelial lesions (HSIL) on cytology as well as with IM clusters on HSIL smears were included. CIN2 tissues and HSIL and IM clusters on Pap smears were isolated by manual microdissection, and HPV types were identified by PCR-based genotyping. The nuclear area within the IM clusters was also measured. The median nuclear area of HPV-negative IM clusters was 48 µm2 , with a coefficient of variation (CV) of 0.20; those of HPV-positive clusters were 66 µm2 and 0.34, respectively. The cut-off values of the nuclear area and CV for HPV positivity were 62 µm2 and 0.25, respectively. IM clusters composed of cells with a nuclear area of more than twice that of neutrophils or cells with a wide variation in nuclear sizes are likely to be neoplastic cells caused by HPV.

Optimal Papanicolaou Smear Conditions for Manual Microdissection of Single Target Cells.

This study aimed to investigate the optimal conditions for Papanicolaou (Pap) smear to increase the success rate of target cell isolation through manual microdissection (MMD) and prevent cell spread. Pap smears were prepared using an HPV42-positive SurePath™ liquid-based cytology case, and 46 and 50 koilocytes were used in wet and dried Pap smears, respectively, to verify the success rate of target cell isolation using MMD based on the HPV detection rate. During MMD, the microscopic examination of both specimens revealed that cells in dried smears could be easily identified; however, cell debris remained in the surrounding area after MMD. Although it was difficult to observe cells in wet smears, there was no cell debris. When the needle tip was immersed in DNA lysate after cell isolation through MMD, a difference in cell solubility was found between dry and wet smears. HPV42 was detected in 94.7% and 97.4% of dried and wet Pap smears, respectively, via polymerase chain reaction genotyping using lysed cell solution; the detection rates were not significantly different. The isolation of target cells from wet Pap smears using MMD reduced the risk of contamination and increased the success rate of HPV detection. This study might facilitate the identification of new CIN-derived HPV-infected cells using MMD with wet Pap smears.

Preferential Tissue Sites of Different Cancer-Risk Groups of Human Papillomaviruses.

The oncogenic potential of human papillomavirus (HPV) may be used to determine the tissue tropism of each HPV type. Cervical cancer develops in the squamo-columar junction of the cervices, and most lesions are induced by high-risk (HR) HPV types. This suggests that HR types preferentially infect the cervix, whereas the preferential infection site for low-risk (LR) types is not well defined. The determination of HPV tropism when using cytology samples can be uncertain since it is difficult to avoid contamination of cell samples between the cervix and the vagina. Herein, cell samples were carefully collected by independently scraping the cervix and vagina, after which the HPV types were determined. HPV tissue tropism was determined by considering what HPV types were positive at only one of the sites (the cervix or the vagina) as the viruses that preferentially infected that site. This method revealed that all LR types were only identified in vaginal samples, whereas 87% of HR types were identified in cervical sites. Thus, LR types may preferentially infect the vagina, whereas HR types infect the cervix. These findings suggest that preferential tissue tropism of certain HPV types is a probable factor for malignant progression.

Pathogen Profiles in Outpatients with Non-COVID-19 during the 7th Prevalent Period of COVID-19 in Gunma, Japan.

The identification of pathogens associated with respiratory symptoms other than the novel coronavirus disease 2019 (COVID-19) can be challenging. However, the diagnosis of pathogens is crucial for assessing the clinical outcome of patients. We comprehensively profiled pathogens causing non-COVID-19 respiratory symptoms during the 7th prevalent period in Gunma, Japan, using deep sequencing combined with a next-generation sequencer (NGS) and advanced bioinformatics technologies. The study included nasopharyngeal swabs from 40 patients who tested negative for severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) using immuno-chromatography and/or quantitative reverse transcription polymerase chain reaction (qRT-PCR) methods. Comprehensive pathogen sequencing was conducted through deep sequencing using NGS. Additionally, short reads obtained from NGS were analyzed for comprehensive pathogen estimation using MePIC (Metagenomic Pathogen Identification Pipeline for Clinical Specimens) and/or VirusTap. The results revealed the presence of various pathogens, including respiratory viruses and bacteria, in the present subjects. Notably, human adenovirus (HAdV) was the most frequently detected virus in 16 of the 40 cases (40.0%), followed by coryneforms, which were the most frequently detected bacteria in 21 of the 40 cases (52.5%). Seasonal human coronaviruses (NL63 type, 229E type, HKU1 type, and OC43 type), human bocaviruses, and human herpesviruses (human herpesvirus types 1-7) were not detected. Moreover, multiple pathogens were detected in 50% of the subjects. These results suggest that various respiratory pathogens may be associated with non-COVID-19 patients during the 7th prevalent period in Gunma Prefecture, Japan. Consequently, for an accurate diagnosis of pathogens causing respiratory infections, detailed pathogen analyses may be necessary. Furthermore, it is possible that various pathogens, excluding SARS-CoV-2, may be linked to fever and/or respiratory infections even during the COVID-19 pandemic.

Molecular Evolutionary Analyses of the Spike Protein Gene and Spike Protein in the SARS-CoV-2 Omicron Subvariants.

To better understand the evolution of the SARS-CoV-2 Omicron subvariants, we performed molecular evolutionary analyses of the spike (S) protein gene/S protein using advanced bioinformatics technologies. First, time-scaled phylogenetic analysis estimated that a common ancestor of the Wuhan, Alpha, Beta, Delta variants, and Omicron variants/subvariants diverged in May 2020. After that, a common ancestor of the Omicron variant generated various Omicron subvariants over one year. Furthermore, a chimeric virus between the BM.1.1.1 and BJ.1 subvariants, known as XBB, diverged in July 2021, leading to the emergence of the prevalent subvariants XBB.1.5 and XBB.1.16. Next, similarity plot (SimPlot) data estimated that the recombination point (breakpoint) corresponded to nucleotide position 1373. As a result, XBB.1.5 subvariants had the 5' nucleotide side from the breakpoint as a strain with a BJ.1 sequence and the 3' nucleotide side as a strain with a BM.1.1.1 sequence. Genome network data showed that Omicron subvariants were genetically linked with the common ancestors of the Wuhan and Delta variants, resulting in many amino acid mutations. Selective pressure analysis estimated that the prevalent subvariants, XBB.1.5 and XBB.1.16, had specific amino acid mutations, such as V445P, G446S, N460K, and F486P, located in the RBD when compared with the BA.4 and BA.5 subvariants. Moreover, some representative immunogenicity-associated amino acid mutations, including L452R, F486V, R493Q, and V490S, were also found in these subvariants. These substitutions were involved in the conformational epitopes, implying that these mutations affect immunogenicity and vaccine evasion. Furthermore, these mutations were identified as positive selection sites. These results suggest that the S gene/S protein Omicron subvariants rapidly evolved, and mutations observed in the conformational epitopes may reduce the effectiveness of the current vaccine, including bivalent vaccines such as mRNA vaccines containing the BA.4/BA.5 subvariants.

Molecular Evolutionary Analyses of the RNA-Dependent RNA Polymerase (RdRp) Region and VP1 Gene in Human Norovirus Genotypes GII.P6-GII.6 and GII.P7-GII.6.

To understand the evolution of GII.P6-GII.6 and GII.P7-GII.6 strains, the prevalent human norovirus genotypes, we analysed both the RdRp region and VP1 gene in globally collected strains using authentic bioinformatics technologies. A common ancestor of the P6- and P7-type RdRp region emerged approximately 50 years ago and a common ancestor of the P6- and P7-type VP1 gene emerged approximately 110 years ago. Subsequently, the RdRp region and VP1 gene evolved. Moreover, the evolutionary rates were significantly faster for the P6-type RdRp region and VP1 gene than for the P7-type RdRp region and VP1 genes. Large genetic divergence was observed in the P7-type RdRp region and VP1 gene compared with the P6-type RdRp region and VP1 gene. The phylodynamics of the RdRp region and VP1 gene fluctuated after the year 2000. Positive selection sites in VP1 proteins were located in the antigenicity-related protruding 2 domain, and these sites overlapped with conformational epitopes. These results suggest that the GII.6 VP1 gene and VP1 proteins evolved uniquely due to recombination between the P6- and P7-type RdRp regions in the HuNoV GII.P6-GII.6 and GII.P7-GII.6 virus strains.

Molecular evolutionary analyses of the fusion protein gene in human respirovirus 1.

Few evolutionary studies of the human respiratory virus (HRV) have been conducted, but most of them have focused on HRV3. In this study, the full-length fusion (F) genes in HRV1 strains collected from various countries were subjected to time-scaled phylogenetic, genome population size, and selective pressure analyses. Antigenicity analysis was performed on the F protein. The time-scaled phylogenetic tree using the Bayesian Markov Chain Monte Carlo method estimated that the common ancestor of the HRV1 F gene diverged in 1957 and eventually formed three lineages. Phylodynamic analyses showed that the genome population size of the F gene has doubled over approximately 80 years. Phylogenetic distances between the strains were short (< 0.02). No positive selection sites were detected for the F protein, whereas many negative selection sites were identified. Almost all conformational epitopes of the F protein, except one in each monomer, did not correspond to the neutralising antibody (NT-Ab) binding sites. These results suggest that the HRV1 F gene has constantly evolved over many years, infecting humans, while the gene may be relatively conserved. Mismatches between computationally predicted epitopes and NT-Ab binding sites may be partially responsible for HRV1 reinfection and other viruses such as HRV3 and respiratory syncytial virus.

Molecular Evolutionary Analyses of the Pseudomonas-Derived Cephalosporinase Gene.

Despite the increasing evidence of the clinical impact of Pseudomonas-derived cephalosporinase (PDC) sequence polymorphisms, the molecular evolution of its encoding gene, blaPDC, remains elusive. To elucidate this, we performed a comprehensive evolutionary analysis of blaPDC. A Bayesian Markov Chain Monte Carlo phylogenetic tree revealed that a common ancestor of blaPDC diverged approximately 4660 years ago, leading to the formation of eight clonal variants (clusters A-H). The phylogenetic distances within clusters A to G were short, whereas those within cluster H were relatively long. Two positive selection sites and many negative selection sites were estimated. Two PDC active sites overlapped with negative selection sites. In docking simulation models based on samples selected from clusters A and H, piperacillin was bound to the serine and the threonine residues of the PDC active sites, with the same binding mode for both models. These results suggest that, in P. aeruginosa, blaPDC is highly conserved, and PDC exhibits similar antibiotic resistance functionality regardless of its genotype.

Rhinovirus Infection and Virus-Induced Asthma.

While the aetiology of asthma is unclear, the onset and/or exacerbation of asthma may be associated with respiratory infections. Virus-induced asthma is also known as virus-associated/triggered asthma, and the reported main causative agent is rhinovirus (RV). Understanding the relationship between viral infections and asthma may overcome the gaps in deferential immunity between viral infections and allergies. Moreover, understanding the complicated cytokine networks involved in RV infection may be necessary. Therefore, the complexity of RV-induced asthma is not only owing to the response of airway and immune cells against viral infection, but also to allergic immune responses caused by the wide variety of cytokines produced by these cells. To better understand RV-induced asthma, it is necessary to elucidate the nature RV infections and the corresponding host defence mechanisms. In this review, we attempt to organise the complexity of RV-induced asthma to make it easily understandable for readers.

Detailed Molecular Interactions between Respiratory Syncytial Virus Fusion Protein and the TLR4/MD-2 Complex In Silico.

Molecular interactions between respiratory syncytial virus (RSV) fusion protein (F protein) and the cellular receptor Toll-like receptor 4 (TLR4) and myeloid differentiation factor-2 (MD-2) protein complex are unknown. Thus, to reveal the detailed molecular interactions between them, in silico analyses were performed using various bioinformatics techniques. The present simulation data showed that the neutralizing antibody (NT-Ab) binding sites in both prefusion and postfusion proteins at sites II and IV were involved in the interactions between them and the TLR4 molecule. Moreover, the binding affinity between postfusion proteins and the TLR4/MD-2 complex was higher than that between prefusion proteins and the TLR4/MD-2 complex. This increased binding affinity due to conformational changes in the F protein may be able to form syncytium in RSV-infected cells. These results may contribute to better understand the infectivity and pathogenicity (syncytium formation) of RSV.

Molecular Evolution of the Pseudomonas aeruginosa DNA Gyrase gyrA Gene.

DNA gyrase plays important roles in genome replication in various bacteria, including Pseudomonasaeruginosa. The gyrA gene encodes the gyrase subunit A protein (GyrA). Mutations in GyrA are associated with resistance to quinolone-based antibiotics. We performed a detailed molecular evolutionary analyses of the gyrA gene and associated resistance to the quinolone drug, ciprofloxacin, using bioinformatics techniques. We produced an evolutionary phylogenetic tree using the Bayesian Markov Chain Monte Carlo (MCMC) method. This tree indicated that a common ancestor of the gene was present over 760 years ago, and the offspring formed multiple clusters. Quinolone drug-resistance-associated amino-acid substitutions in GyrA, including T83I and D87N, emerged after the drug was used clinically. These substitutions appeared to be positive selection sites. The molecular affinity between ciprofloxacin and the GyrA protein containing T83I and/or D87N decreased significantly compared to that between the drug and GyrA protein, with no substitutions. The rate of evolution of the gene before quinolone drugs were first used in the clinic, in 1962, was significantly lower than that after the drug was used. These results suggest that the gyrA gene evolved to permit the bacterium to overcome quinolone treatment.

Effects of Menstrual Cycle on Various Morphologies of High-Grade Squamous Intraepithelial Lesions in SurePath™ Liquid-Based Cervical Cytology.

INTRODUCTION: The morphology of high-grade squamous intraepithelial lesion (HSIL) on Papanicolaou (Pap) smears widely varied, including syncytial aggregates, sheets, and scattered single cells, and no particular cellular pattern is consistently observed. Therefore, this study aimed to determine whether the menstrual cycle affects the cellular pattern of HSILs, an effort to avoid false negatives due to the oversight of scattered small single HSIL cells in the cytological triage of human papillomavirus-positive women. METHODS: A total of 147 HSIL samples of liquid-based cytology (LBC) in patients with cervical intraepithelial neoplasia grade 2 or 3 were obtained, and then, the relationship between cellular patterns, such as single-cell-like and syncytial aggregates, and menstrual cycles classified into six phases was analyzed. If a syncytial aggregate was present, the number of cells constituting the aggregate was visually counted under the microscope. RESULTS: HSILs in scattered single cells and small sheets of <6 on LBC samples accounted for 43% (23/54) during the late proliferative phase of the menstrual cycle. A moderately strong statistically significant association was observed between cellular patterns and menstrual cycles (χ2 [3] = 9.423, p < 0.05) (Cramer's V = 0.253). The value of adjusted residuals showed a statistically significant increased proportion of single-cell-like patterns during the late proliferative phase (p < 0.01). CONCLUSIONS: The present study demonstrated that HSIL cells in Pap smears in the late proliferation phase have a high frequency of single-cell-like patterns. In human papillomavirus-positive Pap smears with a clean background and predominantly superficial cells, careful microscopic observation by targeting single HSIL cells can potentially reduce false negatives.

Causation of cornflake artifacts: Possible association of poor dehydration with drying before mounting in Papanicolaou stain.

Cornflake artifacts are artifacts that commonly occur while the mounted medium starts to evaporate before coverslipping. This study aimed to determine factors contributing to the occurrence of these artifacts in Papanicolaou (Pap) smears. Residual specimens were used after cytology to microscopically evaluate various effects on cornflake artifacts. Four SurePath™ liquid cytology (LBC) cell specimens, diagnosed as negative for intraepithelial lesions or malignancy (NILM), were used. Each LBC smear was subjected to Pap staining under four different conditions (A, without air-drying; B, air-drying after dehydration; C, air-drying after xylene immersion; and D, air-drying after dehydration and xylene immersion) using two methods: conventional and poor dehydration. Cornflake artifacts were not observed in A and B in Pap staining. By contrast, cornflake artifacts were observed in conventional and poor dehydration methods when dried after xylene immersion. When comparing the four conditions, smears B and D, which were both air-dried after dehydration, had fewer cornflake artifacts than smear C, which was air-dried only after xylene. Therefore, the remaining water in the cells due to poor dehydration during xylene immersion is found to result in the development of cornflake artifacts. The present study revealed that cornflake artifacts in Pap smears are caused by poor dehydration in addition to drying before mounting.

Effects of the menstrual cycle on cytological false-negatives in women with persistent cervical intraepithelial neoplasia.

OBJECTIVES: False-negatives on cytology may be observed during follow-ups for patients with persistent cervical intraepithelial neoplasia (CIN); however, the underlying reasons are unknown, and the relationship between the intra-individual variability of false-negatives and the menstrual cycle phase has not been elucidated. Therefore, this study aimed to determine whether the menstrual cycle influences cytological results to maximise the accuracy of such tests. METHODS: A total of 154 liquid-based cytological (LBC) samples were obtained during follow-ups for 26 patients with CIN, and the relationship between cytological results and the menstrual cycle, which was classified into six phases, was analysed. RESULTS: All LBC smears were satisfactory, and 20 of 154 (13.0%) specimens were negative for intraepithelial lesions or malignancy (NILM). A statistically significant association was observed between the cytological results and the phase of the menstrual cycle, χ2 (2) = 19.322, P < 0.01. The association was moderately strong (Cramer's V = 0.354). The value of adjusted residuals showed a statistically significant increase in the NILM percentage as a cytological result during the early secretory phase (P < 0.01) and a statistically significant decrease in NILM during the menstrual and proliferative phases (P < 0.01). CONCLUSIONS: The present study revealed that false-negative cytological results were found to more likely to occur during the early secretory phase. More careful and precise microscopic observation of Pap smears collected at the early secretory phase may contribute to a reduction in the occurrence of false-negatives and improve cytological sensitivity.

Effects of Menstrual Cycle on the Accumulation of Human Papillomavirus-Infected Cells Exfoliated from the Cervix That Drift into the Vagina.

Human papillomavirus (HPV) testing using self-collected vaginal specimens is the preferred choice to increase screening uptake. Although the HPV testing results of these samples depend on the cells that naturally exfoliate from the cervical lesion and drift into the vagina, the mechanism of when and how these exfoliated cells mix with the self-collected sample remains unclear. Hence, the study aimed to clarify the relationship between the vaginal drift of HPV-infected cells exfoliated from the cervix, and the menstrual cycle. A total of 180 scraped samples of the cervix and vagina were examined. The exfoliated cells were classified into two categories according to the HPV genotyping results of each sample: sufficient accumulation (same HPV types in cervical and vaginal samples) and insufficient accumulation (fewer HPV types in vaginal samples than in cervical samples, or HPV positivity in cervical samples and HPV negativity in vaginal samples). A moderately strong statistically significant association was observed between exfoliated cell accumulation and the menstrual cycle, and insufficient accumulation was statistically significantly increased at the early proliferative phases. Self-collection of vaginal samples at the early proliferation phase indicates insufficient sample quantities or lower viral load, thereby affecting HPV genotyping.

Detailed Evolutionary Analyses of the F Gene in the Respiratory Syncytial Virus Subgroup A.

We performed evolution, phylodynamics, and reinfection-related antigenicity analyses of respiratory syncytial virus subgroup A (RSV-A) fusion (F) gene in globally collected strains (1465 strains) using authentic bioinformatics methods. The time-scaled evolutionary tree using the Bayesian Markov chain Monte Carlo method estimated that a common ancestor of the RSV-A, RSV-B, and bovine-RSV diverged at around 450 years ago, and RSV-A and RSV-B diverged around 250 years ago. Finally, the RSV-A F gene formed eight genotypes (GA1-GA7 and NA1) over the last 80 years. Phylodynamics of RSV-A F gene, including all genotype strains, increased twice in the 1990s and 2010s, while patterns of each RSV-A genotype were different. Phylogenetic distance analysis suggested that the genetic distances of the strains were relatively short (less than 0.05). No positive selection sites were estimated, while many negative selection sites were found. Moreover, the F protein 3D structure mapping and conformational epitope analysis implied that the conformational epitopes did not correspond to the neutralizing antibody binding sites of the F protein. These results suggested that the RSV-A F gene is relatively conserved, and mismatches between conformational epitopes and neutralizing antibody binding sites of the F protein are responsible for the virus reinfection.

Profiles of Human Papillomavirus Detection of the Multinucleated Cells in Cervical Smears.

Many genotypes of human papillomaviruses (HPVs) may lead to morphological changes in cells, resulting in various atypical cells, such as multinucleated cells (MNCs) and koilocytes, in the cervix. However, the relationships between the profiles of HPV genotypes and MNCs are not exactly known. Thus, this study comprehensively profiles the HPV genotypes in MNCs using a microdissection method. HPV genotypes and MNCs were detected in 651 cases with an abnormal Pap smear by liquid-based cytology. Specific HPV genotypes were also detected, including HPV16, 34, and 56, which might be associated with MNCs. This result suggests that the high-risk HPV genotypes, such as HPV16 and 56, are associated with the atypical changes in MNC morphology from normal cervical cells. The results also show that MNCs may be a predictor of squamous intraepithelial lesion.

HPV Genotyping by Molecular Mapping of Tissue Samples in Vaginal Squamous Intraepithelial Neoplasia (VaIN) and Vaginal Squamous Cell Carcinoma (VaSCC).

HPV genotypes were determined in 63 vaginal squamous intraepithelial neoplasia (VaIN) and 7 vaginal squamous cell carcinomas (VaSCC). Of these, 37 cases had VaIN alone, and 26 cases had both VaIN and cervical intraepithelial neoplasia (CIN) or condyloma. HPV typing was performed in scraped cells by Genosearch-31 (GS-31) and in the archived tissues by uniplex E6/E7 PCR. In a total of 49 VaIN1, 17 VaIN2/3, and 7 VaSCC tissues, the prevalence of HPV was 91.2% in VaIN (VaIN1: 87.8%, VaIN2/3: 100%) and 85.7% in VaSCC. Comparing HPV results in scraped cell and tissue, 46.2% of high-risk (HR) types and 68.1% of any HPV types that had been identified in cell samples were not present in corresponding tissues. HPV types in VaIN and CIN lesions differed in 92.3% (24/26) of cases with multiple lesions. These results suggest that there are many preclinical HPV infections in the vagina or the cervix, and VaIN and CIN are independently developed. The manual microdissection procedure of tissue revealed one HPV type in one lesion. Seventeen HPV types, including high-risk (HR), possible high-risk (pHR), and low-risk (LR), were identified in 43 VaIN1 lesions. In higher grade lesions, six HR (HPV16, 18, 51, 52, 56, 58), one pHR (HPV66), and one LR (HPV42) HPV types were identified in 17 VaIN2/3, and six HPV types, including HPV16, 45, 58, and 68 (HR), and HPV53 and 67 (pHR), were detected in each case of VaSCC. The vagina appears to be the reservoir for any mucosal HPV type, and HR- or pHR-HPV types are causative agents for vaginal malignancies.

Relationships between Viral Load and the Clinical Course of COVID-19.

To predict the clinical outcome of coronavirus disease-2019 (COVID-19), we examined relationships among epidemiological data, viral load, and disease severity. We examined viral loads of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) in fatal (15 cases), symptomatic/survived (133 cases), and asymptomatic cases (138 cases) using reverse transcription quantitative real-time PCR (RT-qPCR). We examined 5768 nasopharyngeal swabs (NPS) and attempted to detect the SARS-CoV-2 genome using RT-qPCR. Among them, the viral genome was detected using the method for the 370 NPS samples with a positive rate of 6.4%. A comparison of each age showed that the fatal case was higher than the survived case and asymptomatic patients. Survived cases were older than asymptomatic patients. Notably, the viral load in the fatal cases was significantly higher than in symptomatic or asymptomatic cases (p < 0.05). These results suggested that a high viral load of the SARS-CoV-2 in elderly patients at an early stage of the disease results in a poor outcome. We should, therefore, intervene early to prevent a severe stage of the disease in such cases.