Association of Individual Behaviors With Infection Prevention Measures and COVID-19 Development: A Japanese Cross-Sectional Study.

During the COVID-19 pandemic, people often modified their behaviors and performed individual infection control practices despite the uncertain effectiveness of these in preventing COVID-19. A cross-sectional study using a nationwide internet survey (Japan COVID-19 Society Internet Survey) was conducted from September 2022 through October 2022. The questionnaire consisted of individual-level social distancing behaviors and infection prevention measures, and COVID-19 vaccination status. A multivariate logistic regression was performed to determine factors associated with the diagnosis of COVID-19 in the last two months of the survey date. In total, 19,296 respondents were selected for the primary analysis. Of 19,296 respondents, those with COVID-19 diagnosed in the last two months were 1,909 (9.9%). Factors independently associated with a recent history of COVID-19 were meeting colleagues in person ≧ 1 per week (adjusted odds ratio [aOR] 1.72). The response of "never or rarely" to the question of taking out (i.e., dining in) foods was marginally associated with a recent history of COVID-19 (aOR 1.27). Most individual, infection prevention practices and behavioral modifications during the omicron variant phase of the pandemic did not substantially impact COVID-19 prevention in the community.

Usefulness of a pluralistic approach in sentinel surveillance: seasonal influenza activity based on case counts per sentinel site in the National Epidemiological Surveillance of Infectious Diseases Program and test counts, case counts, and test positivity from the National Hospital Organization.

In Japan, based on the National Epidemiological Surveillance of Infectious Diseases (NESID) Program, influenza cases from ~5,000 sentinel sites are monitored weekly as part of influenza surveillance (as number of influenza cases/sentinel site). One limitation is that the number of influenza tests conducted is not reported. Separately, the National Hospital Organization (NHO), with ~140 hospitals, routinely publishes three indicators: number of influenza tests, influenza-positive case counts, and test positivity. We used NESID and NHO data from April 2011 to June 2022 to assess the usefulness of multiple indicators to monitor influenza activity. Temporal trends of the NHO and NESID indicators were similar, and NHO indicator levels well-correlated with those of the NESID indicator. Influenza positivity in the NHO data, however, showed an earlier rise and peak time compared to the NESID indicator. Importantly, through the non-epidemic summer periods and the coronavirus disease 2019 pandemic, a sizable number of influenza tests continued to be done at NHO hospitals, with results showing considerably low case counts and test positivity. These data show that a relatively small number of sentinel sites is sufficient to monitor influenza activity nationally, and, that utilizing multiple indicators can increase our confidence in situational awareness and data interpretations.

Prevalence and trends in persistent symptoms following COVID-19 in Japan: A nationwide cross-sectional survey.

INTRODUCTION: Even during the endemic phase of the COVID-19 pandemic, the impact of persistent symptoms on patients and healthcare systems remains significant. Thus, a more comprehensive understanding of these symptoms is essential. METHODS: Using data from the Japan Society and New Tobacco Internet Survey conducted in February 2023, this cross-sectional study investigated the prevalence of, and changes in, persistent COVID-19 symptoms. RESULTS: In total, 21,108 individuals responded to the survey. Of these, 29.1 % (6143) had a history of COVID-19. Our analysis found that arm/leg/joint pain (adjusted odds ratio [aOR]: 1.17; 95 % confidence interval [95 % CI]: 1.03-1.33), back pain (aOR: 1.13; 95 % CI: 1.01-1.27), chest pain (aOR: 1.53; 95 % CI: 1.20-1.96), malaise (aOR: 1.14; 95 % CI: 1.02-1.28), loss of taste (aOR: 2.55; 95 % CI: 1.75-3.72), loss of smell (aOR: 2.33; 95 % CI: 1.67-3.26), memory impairment (aOR: 1.27; 95 % CI: 1.04-1.56), and cough (aOR: 1.72; 95 % CI: 1.38-2.13) were independently associated with a history of COVID-19 contracted more than two months but less than six months previously. Further, back pain (aOR: 1.24; 95 % CI: 1.04-1.47) and loss of taste (aOR: 2.28; 95 % CI: 1.24-4.21) showed independent association with COVID-19 contracted more than 12 months previously. CONCLUSIONS: Various symptoms were independently associated with a history of COVID-19. While most patients tend to recover within a year after contracting COVID-19, certain symptoms, such as back pain and loss of taste, persist longer than a year, underscoring public health concerns and emphasizing the need for health care services to support patients suffering from persistent symptoms.

Sotos syndrome with marked overgrowth in three Japanese patients with heterozygous likely pathogenic NSD1 variants: case reports with review of literature.

We report three Japanese patients with Sotos syndrome accompanied by marked overgrowth, i.e., a 2 8/12-year-old boy with a height of 105.2 cm (+4.4 SD) (patient 1), the mother of patient 1 with a height of 180.8 cm (+4.1 SD) (patient 2), and a 12 10/12-year-old girl with a height of 189.4 cm (+6.3 SD) (patient 3). In addition to the marked overgrowth (tall stature), patients 1-3 exhibited Sotos syndrome-compatible macrocephaly and characteristic features, whereas intellectual and developmental disabilities remained at a borderline level in patient 1 and were apparently absent from patients 2 and 3. Thus, whole exome sequencing was performed to confirm the diagnosis, revealing a likely pathogenic c.6356A>G:p.(Asp2119Gly) variant in NSD1 of patients 1 and 2, and a likely pathogenic c.6599dupT:p.(Ser2201Valfs*4) variant in NSD1 of patient 3 (NM_022455.5). The results, in conjunction with the previously reported data in nine patients with marked overgrowth (≥4.0 SD), imply that several patients with Sotos syndrome have extreme tall stature even in adulthood. Thus, it is recommended to examine NSD1 in patients with marked overgrowth as the salient feature.

Molecular Epidemiology of Respiratory Syncytial Virus during 2019-2022 and Surviving Genotypes after the COVID-19 Pandemic in Japan.

To evaluate the changes in respiratory syncytial virus (RSV) collected between 2019 and 2022, we analyzed RSV-A and RSV-B strains from various prefectures in Japan before and after the COVID-19 pandemic. RT-PCR-positive samples collected from children with rapid test positivity at outpatient clinics in 11 prefectures in Japan were sequenced for the ectodomain of the G gene to determine the genotype. Time-aware phylogeographic analyses were performed using the second hypervariable region (HVR) of the G gene from 2012 to 2022. Of 967 samples, 739 (76.4%) were found to be RSV-positive using RT-PCR. RSV peaked in September 2019 but was not detected in 2020, except in Okinawa. Nationwide epidemics occurred with peaks in July 2021 and 2022. The genotype remained the same, ON1 for RSV-A and BA9 for RSV-B during 2019-2022. Phylogeographic analysis of HVR revealed that at least seven clusters of RSV-A had circulated previously but decreased to two clusters after the pandemic, whereas RSV-B had a single monophyletic cluster over the 10 years. Both RSV-A and RSV-B were transferred from Okinawa into other prefectures after the pandemic. The RSV epidemic was suppressed due to pandemic restrictions; however, pre-pandemic genotypes spread nationwide after the pandemic.

Full genome-based characterization of an Asian G3P[6] human rotavirus strain found in a diarrheic child in Japan: Evidence for porcine-to-human zoonotic transmission.

Human rotavirus strains having the unconventional G3P[6] genotype have been sporadically detected in diarrheic patients in different parts of the world. However, the full genomes of only three human G3P[6] strains from Asian countries (China, Indonesia, and Vietnam) have been sequenced and characterized, and thus the exact origin and evolution of G3P[6] strains in Asia remain to be elucidated. Here, we sequenced and characterized the full genome of a G3P[6] strain (RVA/Human-wt/JPN/SO1199/2020/G3P[6]) found in a stool sample from a 3-month-old infant admitted with acute gastroenteritis in Japan. On full genomic analysis, strain SO1199 was revealed to have a unique Wa-like genogroup configuration: G3-P[6]-I5-R1-C1-M1-A8-N1-T1-E1-H1. VP6 genotype I5 and NSP1 genotype A8 are commonly found in porcine rotavirus strains. Furthermore, phylogenetic analysis demonstrated that all 11 genes of strain SO1199 were closely related to those of porcine and/or porcine-like human rotaviruses and thus appeared to be of porcine origin. Thus, strain SO1199 was shown to possess a porcine-like genomic backbone and thus is likely to be the result of interspecies transmission of a porcine rotavirus strain. Of note is that all 11 genes of strain SO1199 were phylogenetically located in clusters, distinct from those of the previously identified porcine-like human G3P[6] strains from around the world including Asia, suggesting the occurrence of independent porcine-to-human zoonotic transmission events. To our knowledge, this is the first report on full genome-based characterization of a human G3P[6] strain that has emerged in Japan. Our findings revealed the diversity of unconventional human G3P[6] strains in Asia, and provide important insights into the origin and evolution of G3P[6] strains.

Comparing clinical outcomes of ARB and ACEi in patients hospitalized for acute COVID-19.

Continued receipt of Renin-Angiotensin-Aldosterone inhibitors in patients with COVID-19 has shown potential in producing better clinical outcomes. However, superiority between ACEi (angiotensin-converting enzyme inhibitors) and ARB (angiotensin II receptor blockers) regarding clinical outcomes in this setting remains unknown. We retrospectively collected data on patients hospitalized for acute COVID-19 using the nationwide administrative database (Diagnosis and Procedure Combinations, DPC). The DPC data covered around 25% of all acute care hospitals in Japan. Patient outcomes, with focus on inpatient mortality, were compared between patients previously prescribed ACEi and those prescribed ARB. Comparisons based on crude, multivariate and propensity-score adjusted analysis were conducted. We examined a total of 7613 patients (ARB group, 6903; ACEi group 710). The ARB group showed lower crude in-hospital mortality, compared to the ACEi group (5% vs 8%; odds ratio, 0.65; 95% CI 0.48-0.87), however not in the multivariate-adjusted model (odds ratio, 0.95; 95% CI 0.69-1.3) or propensity-score adjusted models (odds ratio, 0.86; 95% CI 0.63-1.2). ARB shows potential in reducing hospital stay duration over ACEi in patients admitted for COVID-19, but does not significantly reduce in-hospital mortality. Further prospective studies are needed to draw a definitive conclusion, but continuation of either of these medications is warranted to improve clinical outcomes.

Analysis of hydroxychloroquine prescriptions for COVID-19 in Japan.

Number of hydroxychloroquine prescriptions per month for patients with coronavirus disease 2019 (COVID-19) in Japan from January 2020 to November 2021. The blue bars show the monthly number of chloroquine prescriptions for COVID-19 among patients in the Medical Data Vision database, which includes data on approximately 20% of acute care hospitals in Japan. The gray line shows the national number of COVID-19 notifications in Japan by month over the same period.

Prolonged Symptoms after COVID-19 in Japan: A Nationwide Survey of the Symptoms and Their Impact on Patients' Quality of Life.

BACKGROUND: Clinical details of long COVID are still not well understood because of potential confounding with a wide range of pre-existing comorbidities. METHODS: The present study used datasets from a nationwide, cross-sectional, online survey. We determined which prolonged symptoms were more likely to be associated with post-COVID condition after adjusting for a wide range of comorbidities and baseline characteristics. This study also used the EuroQol 5 Dimension 5 Level (EQ-5D-5L) and Somatic Symptom Scale-8 to assess health-related quality of life (QOL) and somatic symptoms in individuals with a previous history of COVID-19, defined as the diagnosis of COVID-19 made at least 2 months prior to the online survey. RESULTS: In total, 19,784 respondents were included for analysis; of these, 2397 (12.1%) had a previous history of COVID-19. The absolute difference of adjusted prevalence of symptoms attributed to prolonged symptoms after COVID-19 ranged from -0.4% to +2.0%. Headache (adjusted odds ratio [aOR]: 1.22; 95% confidence interval [95% CI]:1.07-1.39), chest discomfort (aOR:1.34, 95% CI:1.01-1.77), dysgeusia (aOR: 2.05, 95% CI: 1.39-3.04), and dysosmia (aOR: 1.96, 95% CI: 1.35-2.84) were independently associated with a previous history of COVID-19. Individuals with a previous history of COVID-19 had lower health-related QOL scores. CONCLUSIONS: After adjusting for potential comorbidities and confounders, clinical symptoms, such as headache, chest discomfort, dysgeusia, and dysosmia, were found to be independently associated with a previous history of COVID-19, which was diagnosed 2 or more months previously. These protracted symptoms might have impacted QOL and the overall somatic symptom burden in subjects with a previous history of COVID-19.

Post-COVID health-related quality of life and somatic symptoms: A national survey in Japan.

BACKGROUND: The characteristics and risk factors of post-COVID-19 condition affecting health-related quality of life and the symptom burden are unclear. METHODS: The present, cross-sectional study used the JASTIS (Japan Society and New Tobacco Internet Survey) database. EQ-5D-5L and Somatic Symptom Scale-8 were used to assess health-related quality of life and somatic symptoms, respectively. The participants were classified into a no-COVID-19, COVID-19 not requiring oxygen therapy or COVID-19 requiring oxygen therapy group. First, the entire cohort was analyzed. Then, sensitivity analysis was performed after excluding patients in the no-COVID-19 group with a history of close contact with individuals known to have the disease. FINDINGS: In total, 30130 individuals (mean age: 47.8; females: 51.2%), including 539 and 805 with COVID-19 requiring and not requiring oxygen therapy, respectively, participated. The analysis of the entire cohort as well as the sensitivity analysis demonstrated that individuals with a history of COVID-19 had significantly lower EQ-5D-5L and significantly higher SSS-8 scores than those with no COVID-19 history. The group requiring oxygen therapy was associated with significantly lower EQ-5D-5L and higher SSS-8 scores than the group not requiring oxygen therapy. Propensity-score matching confirmed these results. Furthermore, two or more COVID-19 vaccinations were independently associated with high EQ-5D-5L and low SSS-8 scores (P < 0.001). CONCLUSIONS: The participants with a COVID-19 history, especially those with severe disease, had a significantly higher somatic symptom burden. Analysis after adjusting for potential confounders found that their quality-of-life was also severely affected. Vaccination is crucial to addressing these symptoms, especially in high-risk patients.

Serious mental illness and in-hospital mortality among hospitalized patients with acute COVID-19: A large-database analysis in Japan.

OBJECTIVE: The association of serious mental illness (affective or non-affective psychotic disorders) with higher mortality in patients infected with acute coronavirus disease 2019 (COVID-19) has been suggested. Although this association remains significant after adjusting for medical comorbidities in previous studies, admission clinical status and treatment modalities should be considered as important confounding factors. METHODS: We aimed to assess whether serious mental illness is associated with in-hospital mortality, in patients with COVID-19 by adjusting for comorbidities, admission clinical status, and treatment modalities. Our nationwide cohort in Japan included consecutive patients admitted to 438 acute care hospitals for laboratory-confirmed acute COVID-19 from January 1, 2020 to November 30, 2021. RESULTS: Of 67,348 hospitalized patients (mean [standard deviation] age, 54 [18.6] years; 3891 [53.0%] female), 2524 patients (3.75%) had serious mental illness. In-hospital mortality was 282/2524 (11.17%) among patients with serious mental illness, while it was 2118/64,824 (3.27%) in other patients. In the fully adjusted model, serious mental illness was significantly associated with in-hospital mortality (odds ratio, 1.49; 95% CI, 1.27-1.72). E-value analysis confirmed the robustness of the results. CONCLUSION: Serious mental illness remains a risk for mortality in acute COVID-19 after adjusting for comorbidities, admission clinical status, and treatment modalities. Vaccination, diagnosis, early assessment and treatment should be prioritized for this vulnerable group.

Intravenous methylprednisolone pulse therapy and the risk of in-hospital mortality among acute COVID-19 patients: Nationwide clinical cohort study.

BACKGROUND: Steroids are widely used to modulate the inflammatory reactions associated with coronavirus disease 2019 (COVID-19); however, the optimal upper limit dose of steroid use for acute COVID-19 care remains unclear and currently available data may suffer from a time-dependent bias of no effectiveness or reversed causation given the desperate situation of treatment during this pandemic. Accordingly, the aim of this study was to elucidate the impact of intravenous pulse therapy with methylprednisolone (500 mg or greater per day) on the risk of in-hospital mortality among patients with COVID-19 by controlling for time-dependent bias. METHODS: We performed a prospective cohort study with 67,348 hospitalised acute COVID-19 patients at 438 hospitals during 2020-2021 in Japan. The impact of intravenous methylprednisolone pulse therapy on the risk of in-hospital mortality was examined based on hazard ratios (HRs) and 95% confidence intervals (95% CIs), with stratification according to the status of invasive mechanical ventilation (iMV). Time-dependent bias was controlled for in a marginal structural model analysis, with reference to patients without methylprednisolone therapy. RESULTS: During the study period, 2400 patients died. In-hospital mortality rates of iMV-free patients without or with methylprednisolone pulse therapy were 2.3% and 19.5%, and the corresponding values for iMV-receiving patients were 24.7% and 28.6%, respectively. The marginal structural model analysis showed that intravenous pulse therapy with methylprednisolone was associated with a lower risk of in-hospital mortality among patients receiving-iMV (HR 0.59; 95% CI 0.52-0.68). In contrast, pulse therapy with methylprednisolone increased the risk of in-hospital mortality among iMV-free patients (HR 3.38; 95% CI 3.02-3.79). The benefits of pulse therapy for iMV-receiving patients were greater than in those treated with intermediate/higher doses (40-250 mg intravenously) of methylprednisolone (HR 0.80; 95% CI 0.71-0.89). CONCLUSION: The results of our study suggest that intravenous methylprednisolone showed dose-response efficiencies, and pulse therapy may benefit critically ill patients with acute COVID-19, such as those requiring iMV.

Risk of Underlying Diseases and Effectiveness of Drugs on COVID-19 Inpatients Assessed Using Medical Claims in Japan: Retrospective Observational Study.

Background: Results of earlier studies have demonstrated underlying diseases such as cancer, diabetes mellitus, immunodeficiency, hypertension and heart failure to be risk factors for severe outcomes and mortality. Furthermore, clinical trials have shown that drugs such as antiviral drugs, antibody cocktails, steroids and anti-inflammatory drugs can be expected to prevent severe COVID-19 outcomes and death. Methods: This study, using inpatient records from the Medical Information Analysis Databank covering national hospital organizations in Japan, was conducted to evaluate the effects of underlying diseases and/or administered drugs on mortality. Subjects were all inpatients receiving oxygen administration and inpatients using respiratory ventilators, categorized by three age classes: all ages, patients 65 years old or older, and patients younger than 65 years old. We used logistic regression to analyze outcomes for underlying diseases, administered drugs, age, sex, the proportion of the mutated strains, and vaccine coverage. Results: Patients with hypertension, except for younger inpatients, have a lower risk of mortality (estimated coefficient 0.67 among all inpatients (p < 0.01): 0.77 among inpatients with oxygen therapy (p = 0.02) and 0.57 among inpatients with respiratory ventilation w (p = 0.01)). Except for younger inpatients, antibody cocktail (casirivimab/imdevimab or sotrovimab) administration was associated with a higher probability of survival (estimated coefficient 0.27 among all inpatients (p < 0.01)). It raised the survival probability consistently, although other drugs might have reduced the probability of survival. Conclusion: These findings suggest that antiviral drugs (remdesivir, estimated coefficient 1.44 (p < 0.01)), steroids (dexamethasone, estimated coefficient 1.85 (p < 0.01)), and anti-inflammatory drugs (baricitinib, estimated coefficient 1.62 (p < 0.01), and tocilizumab, estimated coefficient 2.73 (p < 0.01)) might not contribute to survival. These results have not been reported from earlier studies. More sophisticated estimation procedures, such as treatment effect models, are necessary to obtain conclusive results.

Association between hospital internal medicine physician workforce and patient admissions during the COVID-19 pandemic in Japan.

BACKGROUND: Hospital physician workforce in Japan is the lowest among developed countries. Many patients with novel coronavirus disease 2019 (COVID-19) with high risk of mortality could not be hospitalized during case surges in Japan and only about 5% of total acute care beds were used as COVID-19 beds nationwide. However, the relationship between the number of hospital physicians and patient admissions remains unclear. Thus, we aimed to evaluate this relationship in areas with the highest incidences during the surges. METHODS: Data collection was performed for teaching hospitals accredited with the specialty of internal medicine in three prefectures which experienced the highest COVID-19 incidences in Japan (Tokyo, Osaka, Okinawa). Association was examined between the number of full-time physicians (internal medicine staff physicians and residents) and admissions of internal medicine patients through ambulance transport from April 2020 to March 2021. Analysis was conducted separately for community hospitals and university hospitals because the latter have roles as research institutions in Japan. Community hospitals included private, public, and semi-public hospitals. RESULTS: Of 117 teaching hospitals in three prefectures, data from 108 teaching hospitals (83 community hospitals and 25 university hospitals) were available. A total of 102,400 internal medicine patients were admitted to these hospitals during the one-year period. Private hospitals received the greatest mean number of patient admissions (290 per 100 beds), followed by public hospitals (227) and semi-public hospitals (201), and university hospitals (94). Among community hospitals, a higher number of resident physicians per 100 beds was significantly associated with a greater number of patient admissions per 100 beds with beta coefficient of 11.6 (95% CI, 1.5 to 21.2, p = 0.025) admissions by one physician increase per 100 beds. There was no such association among university hospitals. CONCLUSIONS: Community hospitals with many resident physicians accepted more internal medicine admissions through ambulance transport during the COVID-19 pandemic. An effective policy to counter physician shortage in hospitals in Japan may be to increase internal medicine resident physicians among community hospitals to save more lives.

High prevalence of IgE sensitization to inactivated influenza vaccines, yet robust IgG4 responses, in a healthy pediatric population.

BACKGROUND: Anaphylaxis following influenza vaccination is a rare but serious problem. The underlying immune responses are not well understood. This study elucidated the IgE and IgG antibody responses in healthy children and adolescents following inactivated influenza vaccines (IIVs). METHODS: The efficacy and safety of quadrivalent IIV (QIV) and trivalent IIV (TIV) were compared in healthy subjects aged 0-18 years. Serum IIV-specific IgE, IgG, and IgG4 levels (sIgE, sIgG, and sIgG4) were measured with ImmunoCAP. Hemagglutination inhibition (HI) assay was performed for each influenza virus subtype. Sera from earlier patients who developed anaphylaxis to different IIVs were similarly tested. RESULTS: A total of 393 subjects were enrolled: 96 were 6 months-2 years old, 100 were 3-5 years old, 100 were 6-12 years old, and 97 were 13-18 years old. No anaphylaxis was observed. Generally, QIV and TIV induced similar antibody responses. IIV-sIgE levels rose significantly after vaccination in the 6 months-2 years old and 3-5 years old groups, did not change in the 6-12 years old group, and decreased in the 13-18 years old group. In contrast, the IIV-sIgG4/sIgE ratio increased significantly after vaccination in all age groups. Sensitized subjects had significantly higher HI titers and IIV-sIgG levels in the youngest age group and higher IIV-sIgG4 levels in all age groups compared with the non-sensitized. The IIV-sIgG4/sIgE ratio in five patients with anaphylaxis was significantly lower than in age-matched healthy subjects. CONCLUSION: IIVs induce IgE sensitization in healthy children but also robust IgG4 responses that may protect them from anaphylaxis.

Drug effectiveness for COVID-19 inpatients inferred from Japanese medical claim data using propensity score matching.

Background: Earlier studies and clinical trials of Coronavirus 2019 (COVID-19) showed that drugs such as antiviral drugs, antibody cocktails, and steroids and anti-inflammatory drugs can prevent severe outcomes and death. Methods: Observational data in Japan assess drug effectiveness against COVID-19. We applied the average treatment effect model, particularly propensity scoring, which can treat the choice of administered drug as if administration were randomly assigned to inpatients. Data of the Medical Information Analysis Databank, operated by National Hospital Organization in Japan, were used. The outcome was defined as mortality. Subjects were all inpatients, inpatients with oxygen administration, and inpatients using respiratory ventilation, classified by three age classes: all ages, 65 years old or older, and younger than 65 years old. Information about demographic characteristics, underlying disease, administered drug, the proportions of Alpha, Beta and Omicron variant strains, and vaccine coverage were used as explanatory variables for logistic regression. Results: Estimated results indicated that only one antibody cocktail (sotrovimab, casirivimab and imdevimab) was associated with raising the probability of survival consistently and significantly. By contrast, other drugs, an antiviral drug (remdesivir), a steroid (dexamethasone), and an anti-inflammatory drug (baricitinib and tocilizumab) were related to reduce the probability of survival. However, propensity score matching method might engender biased results because of a lack of data such as detailed information related to intervention and potential confounders. Therefore, the effectiveness of some drugs might not be evaluated properly in this study. Conclusions: Results indicate high likelihood that antibody cocktails were consistently associated with high probability of survival, although low likelihood was found for other drugs for older patients with mild to severe severity and all age patients with moderate severity. Further study is necessary in light of the lack of available data.

Prevalence and characteristics of antibiotic prescription for acute COVID-19 patients in Japan.

COVID-19 is a viral infection and does not require antibiotics. The study aimed to elucidate a prescribing pattern of antibiotics for COVID-19. A nationwide cross-sectional study was conducted in Japan. The Diagnosis and Procedure Combinations (DPC) data was used to collect information, covering 25% of all acute care hospitals in the country. In 140,439 COVID-19 patients, 18,550 (13.21%) patients received antibiotics. Antibiotics were prescribed more often in inpatients (10,809 out of 66,912, 16.15%) than outpatients (7741 out of 73,527, 10.53%) (p < 0.001). Outpatient prescription was significantly associated with older patients (odds ratio [OR], 4.66; 95% confidence interval [CI] 4.41-4.93) and a greater Charlson index (OR with one-point index increase, 1.22; 95% CI 1.21-1.23). Inpatient prescription was significantly associated with older patients (OR 2.10; 95% CI 2.01-2.21), male gender (OR 1.12, 95% CI 1.07-1.18), a greater Charlson index (OR with one-point increase, 1.06; 95% CI 1.05-1.07), requirement of oxygen therapy (OR 3.44; 95% CI 3.28-3.60) and mechanical ventilation (OR 15.09; 95% CI 13.60-16.74). The most frequently prescribed antibiotic among outpatients was cefazolin, while that among inpatients was ceftriaxone. Antibiotic prescription is relatively low for acute COVID-19 in Japan. Antibiotic prescription was associated with older age, multi-morbidity, severe disease, and winter season.