COVID-19 severity and corticosteroid treatment have minimal effect on specific antibody production.

BACKGROUND: Dexamethasone is currently administered for Coronavirus disease 2019(COVID-19); however, there are concerns about its effect on specific antibodies' production. The aim of this study was to evaluate whether specific antibodies were affected by COVID-19 severity and corticosteroid treatment. METHODS: Of 251 confirmed COVID-19 patients admitted to our hospital between January 26 and August 10, 2020, the early period of the pandemic, 75 patients with sera within 1 month of onset and 1 month or longer were included in the research. A total of 253 serum samples from these patients were collected. The levels of specific antibodies for severe acute respiratory syndrome coronavirus 2(SARS-CoV-2), immunoglobulin G (IgG) and M (IgM), were measured retrospectively. The results were compared separately of each COVID-19 severity, and with or without corticosteroid treatment. RESULTS: Among the 75 patients, 47, 18, and 10 had mild, moderate, and severe disease, respectively. The median age was 53.0 years and 22 (29%) were women. The most common comorbidities were hypertension and dyslipidemia. Corticosteroids were administered to 20 (27%) and 10 (53%), patients with moderate and severe disease, respectively. The positivity rates IgM increased first, and IgG was almost always positive after day 16, regardless of the severity of COVID-19. On days 6-10, both IgG and IgM positivity rates were higher in patients with moderate disease than in those with mild or severe disease. In patients with moderate disease, IgG positivity was similar over time, regardless of corticosteroid treatment. CONCLUSIONS: In COVID-19 patients, specific IgG is positive and maintained for a long period of time, even after corticosteroid treatment. The effect of corticosteroid treatment in a COVID-19 epidemiological study using specific IgG antibodies was considered minor. COVID-19 patients were more likely to receive oxygen if IgM was positive 1 week after onset, but not mechanical ventilation. IgM measurement 1 week after onset may predict COVID-19 severity.

Autopsy of tetanus with foot gangrene as portal of entry.

Non-traumatic chronic skin lesions are the second most common cause of tetanus. Herein, we describe an 85-year-old woman who presented with a chronically infected skin lesion. She developed tetanus while in hospital and died of respiratory failure, after refusing mechanical ventilation. Routine immunization against tetanus began in Japan during 1968; hence many people born before 1968 are unvaccinated. Mortality due to tetanus is high and the proportion with protective antibodies is low in older adults. Therefore, we recommend tetanus vaccination for older persons in Japan who have chronic skin lesions and have never been vaccinated.

Successful management of persistent COVID-19 using combination antiviral therapy (nirmatrelvir/ritonavir and remdesivir) and intravenous immunoglobulin transfusion in an immunocompromised host who had received CD20 depleting therapy for follicular lymphoma.

The management of persistent symptomatic coronavirus disease 2019 (COVID-19) infections in immunocompromised patients remains unclear. Here, we present the first case of successful antiviral therapy (nirmatrelvir/ritonavir and remdesivir) in combination with intravenous immunoglobulin (IVIg) in a patient who had received CD20 depleting therapy for follicular lymphoma and experienced recurrent COVID-19 relapses. After the patient received IVIg treatment, the viral load decreased without recurrence. Subsequently, it was found that the anti-spike antibody titer in the administered immunoglobulin was high at 9528.0 binding antibody units/mL. Our case highlights the potential of combination therapy with selective IVIg and antiviral drugs for relapsed immunocompromised COVID-19 patients who have received CD20 depleting therapy.

Comparison of the effects of cefmetazole and meropenem on microbiome: A pilot study.

BACKGROUND: Cefmetazole (CMZ) is a carbapenem-sparing option in the treatment of extended-spectrum beta-lactamase (ESBL)-producing bacterial infection. In this pilot study, we aimed to compare the effects of antimicrobial treatment (meropenem [MP] and CMZ) with those of no antimicrobial treatment (control group) on the microbiome. METHODS: The study was a multicenter, prospective, observational pilot study conducted from October 2020 to October 2022. Feces and saliva samples were collected for microbiome analyses at two time points (early-period: days 1-3; and late-period: days 4-30) for the antimicrobial treatment group, and at one time point for the control group. RESULTS: Five feces (MP-F and CMZ-F) and five saliva (MP-S and CMZ-S) samples were included in the MP and the CMZ groups. Ten feces (C-F) and saliva (C-S) samples were included in the control group. Group α diversity was notably lower in the late-period MP-F group than the control group as determined with the Shannon richness index. ß diversity analysis of the feces samples based on weighted and unweighted UniFrac distances revealed distinctions in both the late-period CMZ-F and MP-F groups compared with the control group. Weighted UniFrac analysis showed that only the early-period MP-F group differed from the control group. In the saliva samples, weighted and unweighted UniFrac analyses showed significant differences between the control group and the early CMZ, late CMZ, and late MP groups. CONCLUSIONS: MP treatment may cause larger impact on the feces microbiome than CMZ in Japanese patients.

Clinical outcomes and epidemiological characteristics of bacteremia in the older Japanese population.

BACKGROUND: The characteristics and clinical consequences of bacteremia in older people, who are highly susceptible to infections, need to be clarified. This study aimed to determine the epidemiological characteristics, prognosis, and predictors of 7-day mortality in patients with community-acquired (CA), healthcare-associated (HCA), and hospital-onset (HO) bacteremia in older adults aged ≥65 years. METHODS: Patients aged ≥65 years with positive blood cultures between April 1, 2015, and March 31, 2018, were divided into three groups: pre-old (65-74 years), old (75-89 years), and super-old (≥90 years). Characteristics based on medical exposure, including CA, HCA, and HO, were also compared and factors related to mortality were identified. RESULTS: Overall, 1716 episodes of bacteremia were identified in 1415 patients. Of the 1211 episodes without contamination, 32.8%, 54.3%, and 12.9% occurred in pre-old, old, and super-old patients. Central line-associated bloodstream infections were more common in pre-old patients and urinary tract infections in the old and super-old. The 7-day mortality rates in the pre-old, old, and super-old groups were 7.4%, 5.8%, and 14.2% (P = 0.002), respectively. Multivariable logistic regression showed that super-old age (adjusted odds ratio, aOR: 2.09 [1.13-3.88], P = 0.019) and HO bacteremia (aOR: 1.97 [1.18-3.28], P = 0.010) were independent risk factors for 7-day mortality. Infectious disease consultation had a protective effect on 7-day mortality (aOR: 0.59 [0.35-0.99], P = 0.047). CONCLUSIONS: The epidemiology of bacteremia differs among older people; thus, they should not be treated as a single entity. A careful approach is needed for the optimal management of bacteremia in these vulnerable patients.

Potential usage of anterior nasal sampling in clinical practice with three rapid antigen tests for SARS-CoV-2.

INTRODUCTION: Anterior nasal sampling (AN) might be more convenient for patients than NP sampling to diagnose coronavirus disease. This study investigated the feasibility of rapid antigen tests for AN sampling, and the factors affecting the test accuracy. METHODS: This single-center prospective study evaluated one qualitative (ESP) and two quantitative (LUMI and LUMI-P) rapid antigen tests using AN and NP swabs. Symptomatic patients aged 20 years or older, who were considered eligible for reverse-transcription quantitative polymerase chain reaction using NP samples within 9 days of onset were recruited. Sensitivity, specificity, and positive and negative concordance rates between AN and NP samples were assessed for the rapid antigen tests. We investigated the characteristics that affected the concordance between AN and NP sampling results. RESULTS: A total of 128 cases were recruited, including 28 positive samples and 96 negative samples. The sensitivity and specificity of AN samples using ESP were 0.81 and 1.00, while those of NP samples were 0.94 and 1.00. The sensitivity of AN and NP samples was 0.91 and 0.97, respectively, and specificity was 1.00, for both LUMI and LUMI-P. The positive concordance rates of AN to NP sampling were 0.87, 0.94, and 0.85 for ESP, LUMI, and LUMI-P, respectively. No factor had a significant effect on the concordance between the sampling methods. CONCLUSIONS: ESP, LUMI, and LUMI-P showed practical diagnostic accuracy for AN sampling compared to NP sampling. There was no significant factor affecting the concordance between AN and NP sampling for these rapid antigen tests.

Impact of the COVID-19 pandemic on racial and ethnic minorities in Japan.

This study compared clinico-epidemiological characteristics between Japanese and non-Japanese coronavirus disease 2019 (COVID-19) patients under the pandemic in Japan. We retrospectively analysed nationwide data of hospitalised COVID-19 patients before 31 March 2021. Epidemic curves were constructed to identify the case distribution over time. A total of 28 093 patients were Japanese and 1335 patients were non-Japanese. The major racial and ethnic minorities were East Asians (n = 521), South Asians (n = 260) and Latin Americans (n = 270). Non-Japanese patients were younger and more likely to travel to COVID-19 endemic countries (7.7%), had meals with other people (17.8%), stayed in crowded places (17.9%) and worked mainly in restaurants (6.6%) and service facilities in nightlife businesses (5.2%). In the matched cohorts, we found no clear disparities in time to admission and clinical prognoses. The epidemic curve for non-Japanese patients showed a small peak in the first wave and no definite waves for the second or third waves. Racial and ethnic minorities were at less risk of severe disease but were at a greater risk of COVID-19 exposure; however, the healthcare system in Japan may provide them with equal opportunities to access inpatient care with Japanese. Further research on their social determinants of health in Japan is required.

Comorbidities as Risk Factors for Severe Disease in Hospitalized Elderly COVID-19 Patients by Different Age-Groups in Japan.

INTRODUCTION: Old age is an independent risk factor (RF) for severe COVID-19; evidence for clinico-epidemiological characteristics among elderly COVID-19 patients is scarce. We aimed to analyze clinical and epidemiological characteristics and comorbidities associated with COVID-19 inpatients in age-stratified populations of an elderly COVID-19 cohort. METHODS: We conducted a retrospective cohort study, using nationwide registry data of COVID-19 patients hospitalized before October 31, 2020 (major information entered in the registry as of December 28, 2020). Participants were divided by age according to the Japan Geriatrics Society and the Japan Gerontological Society: pre-old (65-74 years), old (75-89 years), and super-old (≥90 years). Multivariable logistic regression (MLR) analyses were conducted to identify stratified risk and relationships with comorbidities associated with worse outcomes in different age-groups of elderly patients. Demographics and supportive care were evaluated by category. RESULTS: Data of 4,701 patients from 444 hospitals were included. Most patients (79.3%) had at least one comorbidity; the proportion of patients with hypertension was high in all categories. The proportion of patients with dementia, cardiovascular disease, and cerebrovascular disease increased with age. The percentage of patients who underwent invasive mechanical ventilation/extracorporeal membrane oxygenation was lower in the super-old group. In total, 11.5% of patients died (5.3%, pre-old; 15.2%, old; and 22.4%, super-old). MLR showed that the risk of critical illness differed among age-groups. Male sex was a significant RF in all ages. Collagen disease, moderate to severe renal disorder, and dialysis were significant RFs in older patients, while hematological malignancies and metastatic tumors were more important RFs for severe disease in relatively younger patients. Most of the RFs for critical illnesses were associated with death. CONCLUSION: Differences in the epidemiological and clinical characteristics among the different age-groups were found.

Disseminated Streptococcus anginosus invasive infection with intracranial subdural abscess formation.

We report the case of a 67-year-old woman with disseminated Streptococcus anginosus invasive infection. Even under a maximal dose of susceptible antibiotics, her condition was complicated by pulmonary septic emboli and intracranial subdural abscess. Effective antibiotics and emergent surgical drainage were performed, but the sequelae of aphasia and hemiplegia remained. Underlying immunocompromised conditions of diabetes mellitus and monoclonal gammopathy of unknown significance might partially affect the clinical course of invasive S. anginosus infection. Once the infection becomes invasive, it can be refractory and difficult to treat. Clinicians should acknowledge the characteristics of invasive S. anginosus infection.

Clinical characteristics and prognosis of immunosuppressed inpatients with COVID-19 in Japan.

INTRODUCTION: We aimed to analyze the clinical characteristics and outcomes of immunosuppressed inpatients with coronavirus disease 2019 (COVID-19). METHODS: In this observational study, we utilized a large nationwide registry of hospitalized patients with COVID-19 in Japan. Patients' baseline characteristics and outcomes were compared according to the immunosuppressed states of the patients. The impact of different therapeutic agents on the clinical courses of the patients was evaluated. RESULTS: Data of 14,760 patients were included, and 887 (5.9%) were immunosuppressed. The immunosuppressed state of the patient resulted from solid tumor (43.3%, n = 384), chemotherapy within 3 months (15.6%, n = 138), collagen disease (16.9%, n = 150), use of immunosuppressive agents (16.0%, n = 142), and metastatic solid tumor (13.5%, n = 120). Immunosuppressed patients were older and had a higher severity of illness at admission and during hospitalization than non-immunosuppressed patients. The mortality rates for major diseases causing immunosuppression were as follows: solid tumor, 12.5% (48/384; P < 0.001; relative risk [RR], 3.41); metastatic solid tumor, 31.7% (38/120; P < 0.001; RR, 8.43); leukemia, 23.1% (9/39; P < 0.001; RR, 5.87); lymphoma, 33.3% (20/60; P < 0.001; RR, 8.63); and collagen disease, 15.3% (23/150; P < 0.001; RR 3.97). Underlying diseases with high mortality rates were not necessarily associated with high rates of invasive supportive care. CONCLUSIONS: The prognosis of immunosuppressed COVID-19 inpatients varied according to the different immunosuppressed states. Multiple factors, including the severity of the underlying diseases, might have affected their invasive supportive care indications.

Facilitating the deployment of Japanese human resources for responding global outbreaks of emerging and Re-emerging infectious diseases: A cross-sectional study.

INTRODUCTION: In response to global outbreaks of infectious diseases, the need for support from organizations such as the World Health Organization Global Outbreak Alert and Response Network (GOARN) is increasing. Identifying the obstacles and support needs for applicants could increase GOARN deployments from Japan. METHODS: This cross-sectional study involved a web-based, self-administered questionnaire survey targeting Japanese participants in the GOARN Tier 1.5 training workshop, held in Tokyo in December 2019. RESULTS: All 47 Japanese participants in the workshop responded to the survey. Most responders were male and in their 30s and 40s. Participants specialized in case management (42.6%), infection prevention and control (25.6%), epidemiology and surveillance (19.1%). Only two participants (4.6%) had experienced a GOARN deployment. Their motivations for joining the GOARN training workshop were "Desire to be part of an international emerging infectious disease response team" (44.6%), "Interest in making an international contribution" (19.1%), and "Interest in working for the Japanese government in the field of international infectious diseases" (14.9%). Obstacles to GOARN deployments were "Making time for deployments" (45.7%) and "Lack of required professional skills and knowledge" (40.4%). The support needs for GOARN deployments constituted "Periodic simulation training" (51.1%), "Financial support during deployments" (44.7%), and "Technical support for deployments" (40.4%). CONCLUSIONS: Our study revealed the obstacles and support needs of Japanese candidates for GOARN deployment. Making time and upskilling for GOARN deployment were the main obstacles. More practical training (like GOARN Tier 2.0) with other supports are needed. The national framework is desirable to realize these supports.

Factors associated with high antibody titer following coronavirus disease among 581 convalescent plasma donors: A single-center cross-sectional study in Japan.

INTRODUCTION: The ability to predict which patients with a history of coronavirus disease (COVID-19) will exhibit a high antibody titer is necessary for more efficient screening of potential convalescent plasma donors. We aimed to identify factors associated with a high immunoglobulin G (IgG) titer in Japanese convalescent plasma donors after COVID-19. METHODS: This cross-sectional study included volunteers undergoing screening for convalescent plasma donation after COVID-19. Serum anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) S-protein IgG antibodies were measured using a high-sensitivity chemiluminescence enzyme immunoassay. RESULTS: IgG antibodies were measured in 581 patients, 534 of whom had full information of selected independent variables. Multiple linear regression analysis revealed that increasing age (1.037 [1,025, 1.048]), days from symptom onset to sampling (0.997 [0.995, 0.998]), fever (1.664 [1.226, 2.259]), systemic corticosteroid use during SARS-CoV-2 infection (2.382 [1.576, 3.601]), and blood type AB (1.478 [1.032, 2.117]) predict antibody titer. CONCLUSION: Older participants, those who experienced fever during infection, those treated with systemic corticosteroids during infection, those from whom samples were obtained earlier after symptom onset, and those with blood type AB are the best candidates for convalescent plasma donation. Therefore, these factors should be incorporated into the screening criteria for convalescent plasma donation after SARS-CoV-2 infection.

Fatty liver on computed tomography scan on admission is a risk factor for severe coronavirus disease.

OBJECTIVES: To alleviate the overflow of coronavirus disease 2019 (COVID-19) patients in hospitals, less invasive and simple criteria are required to triage the patients. We evaluated the relationship between COVID-19 severity and fatty liver on plain computed tomography (CT) scan performed on admission. METHODS: In this retrospective cohort study, we considered all COVID-19 patients at a large tertiary care hospital between January 31 and August 31, 2020. COVID-19 severity was categorized into severe (moderate and severe) and non-severe (asymptomatic and mild) groups, based on the Japanese National COVID-19 guidelines. Fatty liver was detected on plain CT scan. Multivariate logistic regression analysis was performed to evaluate factors associated with severe COVID-19. RESULTS: Of 222 patients (median age: 52 years), 3.2%, 58.1%, 20.7%, and 18.0% presented with asymptomatic, mild, moderate, and severe COVID-19, respectively. Although 59.9% had no fatty liver on plain CT, mild, moderate, and severe fatty liver occurred in 13.1%, 18.9%, and 8.1%, respectively. Age and presence of fatty liver were significantly associated with severe COVID-19. CONCLUSION: Our study showed that fatty liver on plain CT scan on admission can become a risk factor for severe COVID-19. This finding may help clinicians to easily triage COVID-19 patients.

Novel SARS-CoV-2 Variant in Travelers from Brazil to Japan.

Multiple severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with higher transmission potential have been emerging globally, including SARS-CoV-2 variants from the United Kingdom and South Africa. We report 4 travelers from Brazil to Japan in January 2021 infected with a novel SARS-CoV-2 variant with an additional set of mutations.

How we secured a COVID-19 convalescent plasma procurement scheme in Japan.

BACKGROUND: In order to tackle the COVID-19 pandemic, a COVID-19 convalescent plasma (CCP) procurement program was initiated in Japan in April 2020. The program was a collaboration between a government-managed national hospital, an infectious disease research institute, and a blood banking organization. Each party assumed different responsibilities: recruitment, SARS-CoV-2 antibody profiling, and plasmapheresis; conduction of screening tests; and SARS-CoV-2 blood testing, respectively. METHODS: We adopted a two-point screening approach before the collected CCP was labeled as a CCP product for investigational use, for which we mainly tested anti-SARS-CoV-2 antibody eligibility and blood product eligibility. Anti-SARS-CoV-2 spike protein titer was measured using enzyme-linked immunosorbent assay, and the IC50 value was denoted as the neutralizing activity. Blood donor eligibility was extended beyond the normal blood donation guidelines to include a broader range of participants. After both eligibility criteria were confirmed, participants were asked to revisit the hospital for blood donation, which is a unique aspect of the Japanese CCP program, as most donations are taking place in normal blood donation venues in other countries. Some donors were re-scheduled for repeat plasma donations. As public interest in anti-SARS-CoV-2 antibodies increased, test results were given to the participants. RESULTS: As of September 17, 2020, our collection of CCP products was sufficient to treat more than 100 patients. As a result, projects for administration and distribution are also being conducted. CONCLUSIONS: We successfully implemented a CCP procurement scheme with the goal to expand to other parts of the country to improve treatment options for COVID-19.

Evaluation of High-Sensitivity Cardiac Troponin T Levels in Japanese Patients Recently Recovered From Coronavirus Disease 2019.

BACKGROUND: Several studies have reported elevated troponin levels in coronavirus disease 2019 (COVID-19) patients, so we investigated myocardial damage by measuring high-sensitivity troponin T (hsTnT) levels and analyzed the relationship with comorbidities.Methods and Results:Of 209 patients who recently recovered from COVID-19, 65% had an elevated hsTnT level that was higher than levels in patients with acute phase infection despite most patients (79%) having a mild illness. The hsTnT levels correlated with disease severity, sex, comorbidities, and ACEi and ARB use. CONCLUSIONS: Myocardial damage occurs in the recovery phase of COVID-19, and its evaluation, regardless of patient age, should be considered.

Time-course evaluation of the quantitative antigen test for severe acute respiratory syndrome coronavirus 2: The potential contribution to alleviating isolation of COVID-19 patients.

INTRODUCTION: The automated quantitative antigen test (QAT), which detects severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is suitable for mass screening. However, its diagnostic capability differentiated by time from onset and potential contribution to infectivity assessment have not been fully investigated. METHODS: A retrospective, observational study using nasopharyngeal swab specimens from coronavirus disease (COVID-19) inpatients was conducted using LumipulseⓇ SARS-CoV-2 antigen test. Diagnostic accuracy was examined for the early (up to 10 days after onset) and late (over 10 days after onset) stages. Time-course QAT changes and reverse-transcription quantitative polymerase chain reaction tests results were displayed as locally estimated scatterplot smoothing curve, and receiver operating characteristic curve (ROC) analysis was used to determine the appropriate cutoff value for differentiating the early and late stages. RESULTS: We obtained 100 specimens from 68 COVID-19 patients, including 51 early-stage and 49 late-stage specimens. QAT sensitivity and specificity were 0.82 (0.72-0.90) and 0.95 (0.75-0.99) for all periods, 0.93 (0.82-0.98) and 1.00 (0.39-1.00) for the early stage, and 0.66 (0.48-0.82) and 0.93 (0.69-0.99) for the late stage, respectively. The ROC analysis indicated an ideal cutoff value of 6.93 pg/mL for distinguishing early-from late-stage specimens. The sensitivity, specificity, positive predictive value, and negative predictive value for predicting the late stage were 0.76 (0.61-0.87), 0.76 (0.63-0.87), 0.76 (0.61-0.87), and 0.76 (0.63-0.87). CONCLUSIONS: QAT has favorable diagnostic accuracy in the early COVID-19 stages. In addition, an appropriate cutoff point can potentially facilitate rapid identification of noncontagious patients.

Infection with capsular genotype K1-ST23 hypervirulent Klebsiella pneumoniae isolates in Japan after a stay in East Asia: Two cases and a literature review.

Disseminated community-acquired infections caused by the hypervirulent Klebsiella pneumoniae (hvKp) among relatively healthy individuals in East Asia have been reported in recent years. Isolate of the capsular genotype K1, belonging to sequence type (ST) 23, is the most common causative agent of this disease. We experienced two cases of K1-ST23 infection with a travel history in East Asia, and hvKp infection was diagnosed after entering or returning to Japan. Case 1 was a 45-year-old Myanmar seaman with a history of ischemic heart disease who developed a fever on board and was transported to Japan via Shanghai and Taiwan. He had multiple disseminated lesions due to K. pneumoniae; other symptoms included liver abscess, intraocular inflammation, intraventricular thrombosis, brain abscess, and bloodstream infection. Along with antimicrobial treatment, drainage of liver abscesses and surgery for intraocular inflammation and intraventricular thrombosis were required. The patient was discharged 93 days after admission, with little improvement in the visual acuity. Case 2: A 29-year-old Japanese man with no underlying disease developed a prostate abscess and bloodstream infection caused by K. pneumoniae after a trip to Korea. However, he improved only with antimicrobial treatment. K. pneumoniae in both cases were identified to have the rmpA gene, with capsular genotypes K1 and ST23. Further, both cases were considered to have been infected with hvKp during their stay in East Asia. In conclusion, it is important to suspect disseminated disease and perform a systemic search, taking into account that hvKp may be present in cases of Klebsiella infection acquired from East Asia.

No SARS-CoV-2 RNA detected in the convalescent plasma of COVID-19 patients with different disease severity.

INTRODUCTION: Convalescent plasma transfusion (CPT), a potential therapy for coronavirus disease 2019 (COVID-19), requires strict quality control of the donor blood. Whether to confirm the disappearance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA (RNAemia) in convalescent donor blood or not is unclear. Reports recommending the proof of viral disappearance from the blood are controversial. Foreseeing CPT in treating COVID-19 patients in Japan, we investigated RNAemia in 100 convalescent donors with mild, moderate, and severe COVID-19. METHODS: Between April 30 and July 30, 2020, we measured RNAemia in the plasma samples of donors with resolved COVID-19. Data on patients' demographics, comorbidities, pneumonia, treatment, and real-time polymerase chain reaction results for SARS-CoV-2 were collected. Date of onset of initial symptoms or date of positive testing (for asymptomatic patients) were self-reported by the patients. Disease severity was defined as: no, mild, moderate oxygen demand, or severe (requiring mechanical ventilation). RESULTS: Of 100 donors (58 males [58.0%]; median age, 47 [range 22-69] years) screened as of July 30, 2020, 77 (77.0%); 19 (19.0%); and 4 (4.0%) had mild, moderate, and severe disease, respectively. Median time between onset and testing was 68.5 (range, 21-167) days. SARS-CoV-2 RNA was not detected in any of the plasma samples. CONCLUSION: RNAemia was not found in recovered COVID-19 patients at least 21, 27, and 57 days after the onset of mild, moderate, and severe symptoms. Our study may contribute to determining a suitable time for collecting convalescent plasma from COVID-19 patients and to future CPT use.

Effectiveness of personal protective equipment in preventing severe acute respiratory syndrome coronavirus 2 infection among healthcare workers.

INTRODUCTION: Information on the effectiveness of personal protective equipment (PPE) for preventing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among healthcare workers (HCWs), especially among HCWs with frequent contact with patients with SARS-CoV-2, is limited. METHODS: We conducted a prospective cohort study on 49 HCWs who worked in close contact with patients with SARS-CoV-2 infection. HCWs had blood samples taken every 2 weeks to test for SARS-CoV-2 antibodies using two different types of assay. RESULTS: Forty-nine participants (31 nurses, 15 doctors, 3 other workers) were enrolled. In total, 112 blood samples are obtained from participants. The median work days in 2 weeks was 9 (interquartile range (IQR): 5-10) days. In a single work day, 30 of the 49 participants (61.5%) had contact with patients with suspected or conformed SARS-CoV-2 at least 8 times, and approximately 60% of participants had more than 10 min of contact with a single patient. The median self-reported compliance to PPE was 90% (IQR: 80-100%). Seven participants tested positive for SARS-CoV-2 antibody using enzyme-linked immunosorbent assay (ELISA); however, none were seropositive for SARS-CoV-2 neutralizing antibody, so the positive ELISA results were assumed to be false-positive. CONCLUSIONS: The study provides evidence that appropriate PPE is sufficient to prevent infection amongHCWs. It is necessary to establish a system that provides a stable supply of PPE for HCWs to perform their duties.