Efficacy and viral dynamics of tecovirimat in patients with MPOX: A multicenter open-label, double-arm trial in Japan

INTRODUCTION

Tecovirimat's application in treating mpox remains under-researched, leaving gaps in clinical and virological understanding.

METHODS

The Tecopox study in Japan evaluated the efficacy and safety of tecovirimat in patients with smallpox or mpox, who were divided into oral tecovirimat and control groups. Patients with mpox enrolled between June 28, 2022, and April 30, 2023, were included. Demographic and clinical details along with blood, urine, pharyngeal swab, and skin lesion samples were gathered for viral analysis. A multivariable Tobit regression model was employed to identify factors influencing prolonged viral detection.

RESULTS

Nineteen patients were allocated to the tecovirimat group, and no patients were allocated to the control group. The median age was 38.5 years, and all patients were males. Ten patients (52.6%) were infected with human immunodeficiency virus (HIV). Sixteen patients (84.2%) had severe disease. Nine of the 15 patients (60.0%) (four patients withdrew before day 14) had negative PCR results for skin lesion specimens 14 days after inclusion. The mortality rates were 0% on days 14 and 30. No severe adverse events were reported. HIV status and the number of days from symptom onset to tecovirimat administration were associated with lower Ct values (p = 0.027 and p < 0.001, respectively). The median number of days when PCR testing did not detect the mpox virus in each patient was 19.5 days.

CONCLUSION

Early tecovirimat administration might reduce viral shedding duration, thereby mitigating infection spread. Moreover, patients infected with HIV showed prolonged viral shedding, increasing the transmission risk compared to those without HIV.

Cumulative antibiogram preparation among hospitals participating in the Japan Surveillance for Infection Prevention and Healthcare Epidemiology

BACKGROUND

The cumulative antibiogram is essential to guide empirical therapy for infectious diseases and monitor the trend of antimicrobial resistance. However, the status of antibiogram generation at medical institutions in Japan is uncertain.

METHODS

A web-based questionnaire survey was conducted in February 2023 on the status of antibiogram preparation among facilities participating in the Japan Surveillance for Infection Prevention and Healthcare Epidemiology (J-SIPHE), an infection control surveillance system in Japan.

RESULTS

The questionnaire collection rate was 19.6% (379/1931). Of all facilities, 47% (178/379) performed microbiological tests mainly in-house, while 53% (201/379) performed microbiological tests mainly outsourced. Of all facilities, 78% (296/379) prepared antibiograms. Of those without antibiograms, 33% (27/83) were considering the development in the future. Some facilities cited staff shortage as a barrier to preparing antibiograms. Of the 214 facilities with antibiograms that could use the J-SIPHE system to prepare antibiograms, 19% (41/214) were using the J-SIPHE system to prepare their antibiograms.

CONCLUSIONS

One-quarter of the facilities that responded to the survey had not prepared antibiograms. Technical support for surveillance and awareness activity for using cumulative antibiograms might promote antibiogram preparation in Japan, which may improve antimicrobial stewardship and antimicrobial resistance measures.

Disease burden of main bacterial infections in Japan, 2015-2020: A population-level study

INTRODUCTION

Comprehensive evidence about the burden of infectious diseases in the Western Pacific Region is scarce. We thus examined the disease burden of infectious diseases in Japan in terms of disability-adjusted life years (DALYs).

METHODS

We extracted national claims data from Japan's universal health insurance system to estimate the burden of disease for selected infections between 2015 and 2020 using DALYs. The mortality rate, disability duration and severity weight of each disease were estimated based on national data and literature reviews.

RESULTS

Disease burden per 100,000 population was 1307.0 in 2015 and 972.1 in 2020 for bloodstream infections (BSI), 796.5 DALYs in 2015 and 498.9 DALYs in 2020 for pneumonia, 171.5 in 2015 and 149.4 in 2020 for meningitis and 11.6 in 2015 and 11.4 in 2020 for urinary tract infections (UTI). Only surgical site infections (SSI) showed a slightly increasing trend over the 5-year period, from 2.2 in 2015 to 2.8 in 2020.

CONCLUSIONS

Our results showed that the disease burden of the five major infectious diseases was higher in Japan than in other countries. However, while the burden of SSI increased, the burden of pneumonia, meningitis, BSI and UTI gradually decreased year on year. The possible causes of the decreased morbidity should be examined in future work.

Bloodstream infections in the elderly Japanese population: Current reality and countermeasures

We reviewed bloodstream infections in the elderly in Japan, referring to data recently reported from the National Center for Global Health and Medicine in Tokyo. We divided the locations of bloodstream infections into Hospital-onset (HO), healthcare-associated (HCA), and CA (community-acquired), as the elderly reside in different places. The study focused on the fact that the general condition and underlying diseases of the elderly differ by age group. And thus, we divided them into three groups: Pre-old (65-74 years), Old (75-89 years), and Super-old (≥ 90 years), and compared their characteristics of bloodstream infections. HO bacteremia was most common in the pre-old group. On the other hand, HCA bloodstream infections tended to increase as the population aged, and it was most prevalent in super-old group. According to the study results, early intervention through infectious diseases (ID) consultation may improve the prognosis of bloodstream infections even in the elderly. Since the rate of ID consultation is lower in the super-old group than in other groups, this group may be a significant target. In conclusion, a study of a cohort of elderly patients with bloodstream infections in Japan indicates that bloodstream infections in patients over 65 years is not uniform.

Pyelonephritis due to Escherichia coli in the older population in Japan: Impacts on activities of daily living and medical costs

This study aimed to investigate differences in Activities of Daily Living (ADL), at admission and discharge, as well as the medical costs of pyelonephritis in older adults in Japan. Patients hospitalized for pyelonephritis between January 1, 2013 and March 31, 2019, were retrospectively enrolled. The inclusion criteria were urine culture within 48 h of admission with > 104 colony-forming units/mL of Escherichia coli and symptoms of pyelonephritis. Patients were divided into Young (20-64 years), Pre-old (65-74 years), Old (75-84 years), and Super-old (≥ 85 years). ADL and medical costs were compared. Finally, 393 patients were included: 112 (28.5%) were Young, 72 (18.3%) were Pre-old, 130 (33.1 %) were Old, and 79 (20.1%) were Super-old between January 1, 2013, and March 31, 2019. The median differences between Barthel Index (BI) scores, which indicates ADL, at admission and discharge were 0, 0, 25, and 23 in each age group, respectively (p < 0.001). No significant differences existed between the groups aged ≥ 65. Median medical costs were $3,368, $4,894, $5,372, and $6,078 for each age group, respectively (p < 0.001). Medical costs per day did not differ significantly between the groups (p = 0.163). Pyelonephritis due to E. coli in patients aged ≥ 75 is associated with a decline in ADL, longer hospital stays, and higher medical costs compared to that in young patients. Pre-old patients did not have lower ADL; however, they tended to have longer hospital stays and higher medical costs.

Unfractionated Heparin Safety in COVID-19: Incidence and Risks of Bleeding Complications in Japan

AIM

Several studies have shown the efficacy and safety of low-molecular-weight heparin use in coronavirus disease 2019 (COVID-19), but that of unfractionated heparin (UFH) has not been investigated. We investigated the prevalence of bleeding complications during UFH administration, its impact on mortality, and the risk factors of bleeding outcomes associated with UFH.

METHODS

This retrospective cohort study was conducted at a single-center tertiary care hospital, including hospitalized patients with COVID-19. The primary outcomes were measured as the prevalence of bleeding complications during hospitalization, and the secondary outcomes were thromboembolic events and 60-day mortality rates. Logistic regression analysis and propensity score matching were used to assess risk factors for bleeding complications and their impact on mortality.

RESULTS

Among 1035 included patients, 516 patients were treated with UFH. Twelve (2.3%) patients in the UFH group experienced major bleeding. The prevalence of major bleeding in patients treated with therapeutic-dose UFH was 9.2%. Logistic regression analysis showed that age ≥ 60 years (adjusted odds ratio [aOR], 3.89; 95% confidence interval [CI], 1.01-15.0; P＜.05) and COVID-19 severity (aOR, 35.9; 95% CI, 4.57-282; P ＜.05) were associated with major bleeding complications. After propensity score matching, 11 major and 11 non-major bleeding cases (including minor bleeding) were matched. The 60-day cumulative mortality rate between the two groups did not differ significantly (P=.13, log-rank test).

CONCLUSIONS

The incidence of major bleeding in COVID-19 patients using therapeutic-dose UFH was relatively high. Critical COVID-19 and older age were risk factors for bleeding complications.

Epidemiology of post-COVID conditions beyond 3 years and factors associated with their persistence longer than 2 years: A cross-sectional study

OBJECTIVE

This study aimed to investigate the epidemiology of post-coronavirus disease 2019 (COVID-19) conditions (PCCs) beyond 3 years and identify factors associated with their persistence longer than 2 years.

STUDY DESIGN

Cross-sectional questionnaire-based survey.

METHODS

We surveyed patients who had recovered from COVID-19 and visited our institution from February 2020 to November 2021. Demographic and clinical data and information on the presence and duration of PCCs were obtained. We identified factors associated with the persistence of PCCs longer than 2 years using multivariate linear regression analyses.

RESULTS

Among 935 patients surveyed, 407 completed the survey. Among them, 360 patients had mild disease in the acute phase. The proportions of participants with at least one symptom at 1, 2, and 3 years after symptom onset or COVID-19 diagnosis were 33.2%, 29.8%, and 5.7%, respectively. The numbers of participants with and without any residual symptoms 2 years after the onset of COVID-19 were 87 and 193, respectively. After multivariate adjustment, persistence of PCCs longer than 2 years was associated with lower body mass index, presence of any underlying medical conditions, and number of symptoms lasting for more than 1 month ≥ 5.

CONCLUSIONS

The prevalence of PCCs decreased 2 years after symptom onset or COVID-19 diagnosis. We also identified factors associated with PCC persistence longer than 2 years, which could help primary care physicians and patients with PCCs predict the duration of PCCs and better understand their natural history, thus reducing patients' anxiety about their duration.

Analysis of Differences in Characteristics of High-Risk Endemic Areas for Contracting Japanese Spotted Fever, Tsutsugamushi Disease, and Severe Fever With Thrombocytopenia Syndrome

Background

Tick-borne infections, including tsutsugamushi disease, Japanese spotted fever, and severe fever with thrombocytopenia syndrome (SFTS), are prevalent in East Asia with varying geographic distribution and seasonality. This study aimed to investigate the differences in the characteristics among endemic areas for contracting each infection.

Methods

We conducted an ecologic study in Japan, using data from a nationwide inpatient database and publicly available geospatial data. We identified 4493 patients who were hospitalized for tick-borne infections between July 2010 and March 2021. Mixed-effects modified Poisson regression analysis was used to identify factors associated with a higher risk of contracting each tick-borne disease (Tsutsugamushi, Japanese spotted fever, and SFTS).

Results

Mixed-effects modified Poisson regression analysis revealed that environmental factors, such as temperature, sunlight duration, elevation, precipitation, and vegetation, were associated with the risk of contracting these diseases. Tsutsugamushi disease was positively associated with higher temperatures, farms, and forests, whereas Japanese spotted fever and SFTS were positively associated with higher solar radiation and forests.

Conclusions

Our findings from this ecologic study indicate that different environmental factors play a significant role in the risk of transmission of tick-borne infections. Understanding the differences can aid in identifying high-risk areas and developing public health strategies for infection prevention. Further research is needed to address causal relationships.

Real-world effectiveness of full and booster mRNA vaccination for coronavirus disease 2019 against disease severity during the delta- and omicron-dominant phases: A propensity score-matched cohort study using the nationwide registry data in Japan

BACKGROUND

To date, few studies from the Asian region have reported the effectiveness of messenger ribonucleic acid coronavirus disease 2019 (COVID-19) vaccines against disease progression and death after hospitalization.

METHODS

We evaluated the data from the COVID-19 registry in Japan during the delta- and omicron-dominant phases. A propensity score-matched cohort study was conducted between the incompletely (0-1 dose) and fully (2 doses) vaccinated groups during the delta-dominant phase and among the incompletely, fully, and booster (3 doses) vaccinated groups during the omicron-dominant phase.

RESULTS

In the delta-dominant phase, 411 pairs were matched. The fully vaccinated group showed a significantly lower oxygen supplementation rate (24.1 % vs. 41.1 %, p < 0.001) but little difference in the mortality rate (2.2 % vs. 2.9 %, p = 0.66). In the omicron-dominant phase, 1494 pairs from the incompletely and fully vaccinated groups, and 425 pairs from the fully and booster vaccinated groups were matched. Full vaccination reduced both the oxygen supplementation rate (18.6 % vs 25.7 %, p < 0.001) and mortality rate (0.7 % vs 2.3 %, p < 0.001). Booster vaccination showed little difference in either the rate of oxygen supplementation (21.2 % vs. 24.7 %, p = 0.25) or mortality (1.2 % vs. 2.6 %, p = 0.21) compared with full vaccination.

CONCLUSIONS

Full vaccination reduced disease severity during the delta- and omicron-dominant phases; booster vaccination did not further enhance the protective effects against disease progression during the omicron-dominant phase compared to full vaccination. Future vaccine strategies and policy decisions should consider preventing infection or disease progression in the target population, as well as the characteristics of the dominant variant in that phase.

Differences in COVID-19 treatment across Japan: Analysis of the COVID-19 Registry Japan (COVIREGI-JP)

BACKGROUND

This study investigated the differences between metropolitan and non-metropolitan areas in the treatment of hospitalized patients with COVID-19 using data from the nationwide COVID-19 Registry Japan (COVIREGI-JP).

METHODS

Data of patients hospitalized for COVID-19 during waves 2-4 (June 1, 2020-June 30, 2021) treated in one of the 800 medical institutions participating in the Registry were extracted. Treatment and treatment outcomes were evaluated in inpatients with moderate 2 and severe disease using propensity score matching performed between metropolitan and non-metropolitan areas.

RESULTS

A total of 32797 patients were identified during epidemic waves 2-4. After matching (wave 2, n = 307; wave 3, n = 913; wave 4, n = 479), the population comprised mostly elderly patients with a median age of ≥65 years (IQR: 52-81 years) and median SpO2 of 93/94 (IQR: 91%-96%), and the proportion of patients with moderate 2 (SpO2≤93%/require oxygenation) vs severe disease (ICU admission) ranged from 82.7% to 89.8% vs 10.2% to 17.3% in metropolitan areas vs non-metropolitan areas, respectively, across all epidemic waves. Noninvasive mechanical ventilation was used significantly more in waves 2 and 3 and invasive mechanical ventilation in wave 4 in metropolitan vs non-metropolitan areas, compared with other waves. In wave 2, death as an outcome was significantly higher in metropolitan vs non-metropolitan areas compared with patient discharge to home/transfer.

CONCLUSION

During the COVID-19 epidemic, starting from wave 2 up until and through wave 4, no clear differences in mortality rates and no regional differences in treatment provision patterns were observed between metropolitan and non-metropolitan areas in Japan.

Factors Associated with Geographical Variability of Antimicrobial Use in Japan

INTRODUCTION

Evidence regarding the factors affecting the geographical variation of antimicrobial use (AMU) is relatively scarce. This study aimed to evaluate factors potentially associated with geographical variability of AMU per day per 1000 habitants in the 47 prefectures of Japan.

METHODS

This is an observational ecological study using the Japanese national database in 2019. The outcome was the defined daily doses per 1000 inhabitants per day by prefecture. Multivariable negative binomial regression analysis was conducted using patient- and physician-level variables.

RESULTS

The study included 605,391,054 defined daily doses of AMU in 2019 from the 47 prefectures. In the multivariable negative binomial regression analyses for the outcome of total AMU, the proportion of female individuals (adjusted rate ratio [aRR] 1.04 [1.01-1.08] per 1% increase, p = 0.021), the proportion of upper secondary graduates going to further education (aRR 1.01 [1.00-1.01] per 1% increase, p = 0.005), and the annual number of diagnoses related to upper respiratory infections (URIs) per 1000 inhabitants per day (aRR 1.21 [1.10-1.34], p < 0.001) were significantly correlated with total AMU.

CONCLUSIONS

In this ecological study, the variability of total AMU by Japanese prefecture was associated with the proportion of female individuals, education level, and the number of URI diagnoses per population. The results suggest the potential need for additional stewardship efforts to reduce unnecessary antimicrobial prescriptions for URI.

Association between seasonal influenza vaccination and antimicrobial use in Japan from the 2015-16 to 2020-21 seasons: from the VENUS study

BACKGROUND

Seasonal influenza vaccination might be considered an antimicrobial resistance (AMR) countermeasure because it can reduce unnecessary antimicrobial use for acute respiratory infection by mitigating the burden of such diseases.

OBJECTIVES

To examine the association between seasonal influenza vaccination and antimicrobial use (AMU) in Japan at the community level and to examine the impact of influenza vaccination on the frequency of unnecessary antimicrobial prescription for upper respiratory infection.

METHODS

For patients who visited any healthcare facility in one of the 23 wards of Tokyo, Japan, due to upper respiratory infection and who were aged 65 years or older, we extracted data from the Vaccine Effectiveness, Networking, and Universal Safety (VENUS) study database, which includes all claims data and vaccination records from the 2015-16 to 2020-21 seasons. We used the average treatment effect (ATE) with 1:1 propensity score matching to examine the association of vaccination status with frequency of antibiotic prescription, frequency of healthcare facility consultation, risk of admission and risk of death in the follow-up period of the same season (from 1 January to 31 March).

RESULTS

In total, 244 642 people were enrolled. Matched data included 101 734 people in each of the unvaccinated and vaccinated groups. The ATE of vaccination was -0.004 (95% CI -0.006 to -0.002) for the frequency of antibiotic prescription, -0.005 (-0.007 to -0.004) for the frequency of healthcare facility consultation, -0.001 (-0.002 to -0.001) for the risk of admission and 0.00 (0.00 to 0.00) for the risk of death.

CONCLUSIONS

Our results suggest that seasonal influenza vaccination is associated with lower frequencies of unnecessary antibiotic prescription and of healthcare facility consultation.

Trends in teicoplanin loading dose implementation from 2010 to 2019 and evaluation of safety and efficacy factors: a retrospective cohort study based on a Japanese administrative claims database

BACKGROUND

The loading dose of teicoplanin (TEIC) is recommended for implementation. However, there is significant discrepancy between the dose settings in the package insert and, in the guidelines, and the actual status of loading doses in Japan is unclear. Furthermore, TEIC causes liver injury as side effect. Although the risk of developing liver injury has not been reported to be increased following a loading dose based on the guidelines, there is a lack of reports in large populations. Therefore, we evaluated the trend in the loading dose and factors affecting the efficacy and safety of TEIC administration.

METHODS

A Japanese administrative claims database was used in this study. Trends in loading doses were evaluated in target populations administered TEIC between 2010 and 2019. Patient characteristics were adjusted by propensity score matching based on the guideline group (total dose of 3 days > 1,600 mg) and non-guideline group (≤ 1,600 mg) of the loading dose. Finally, univariable and multivariable conditional logistic regression analysis was performed to evaluate factors affecting 30-day mortality and liver injury.

RESULTS

A total of 10,030 patients were selected based on these criteria. The proportion of loading doses based on the recommended guidelines showed an increase over time, regardless of the implementation of therapeutic drug monitoring (TDM), but especially so in cases where TDM was implemented, the loading doses were administered in accordance with the recommendations of the guidelines. Conditional logistic regression analysis showed a relationship between drug management and guidance fees (odds ratio [OR]: 0.45, 95% confidence interval [CI]: 0.36‒0.55), a reimbursement indicating pharmacist intervention, and a reduction in 30-day mortality. In addition, loading doses based on the recommended guidelines had no influence on liver injury, and other factors were not significantly associated with increased incidence of liver injury.

CONCLUSION

Thus, this study implies the benefits of pharmacological management as indicated by drug management and guidance fee and supports the implementation of loading doses based on the guideline on TEIC administration.

Effectiveness of cefmetazole versus meropenem for invasive urinary tract infections caused by extended-spectrum β-lactamase-producing Escherichia coli

Cefmetazole is active against extended-spectrum β-lactamase-producing Escherichia coli (ESBLEC) and is a potential candidate for carbapenem-sparing therapy. This multicenter, observational study included patients hospitalized for invasive urinary tract infection due to ESBLEC between March 2020 and November 2021 at 10 facilities in Japan, for whom either cefmetazole or meropenem was initiated as a definitive therapy within 96 h of culture collection and continued for at least 3 d. Outcomes included clinical and microbiological effectiveness, recurrence within 28 d, and all-cause mortality (14 d, 30 d, in-hospital). Outcomes were adjusted for the inverse probability of propensity scores for receiving cefmetazole or meropenem. Eighty-one and forty-six patients were included in the cefmetazole and meropenem groups, respectively. Bacteremia accounted for 43% of the cefmetazole group, and 59% of the meropenem group. The crude clinical effectiveness, 14 d, 30 d, and in-hospital mortality for patients in the cefmetazole and meropenem groups were 96.1% vs 90.9%, 0% vs 2.3%, 0% vs 12.5%, and 2.6% vs 13.3%, respectively. After propensity score adjustment, clinical effectiveness, the risk of in-hospital mortality, and the risk of recurrence were similar between the two groups (P = 0.54, P = 0.10, and P = 0.79, respectively). In all cases with available data (cefmetazole : n = 61, meropenem : n = 22), both drugs were microbiologically effective. In all isolates, bla CTX-M was detected as the extended-spectrum β-lactamase gene. The predominant CTX-M subtype was CTX-M-27 (47.6%). Cefmetazole showed clinical and bacteriological effectiveness comparable to meropenem against invasive urinary tract infection due to ESBLECs.

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.

Protocol of Tecopox study: a multicentre, open-label, double-arm trial to evaluate the efficacy and safety of oral tecovirimat therapy for patients with smallpox or monkeypox

INTRODUCTION

Monkeypox was originally endemic locally in West Africa; however, outbreaks in non-endemic countries have been recognised since May 2022. The effectiveness of tecovirimat has been estimated against smallpox, which belongs to the same Orthopoxvirus genus as monkeypox. Thus, tecovirimat is expected to be effective against monkeypox. This study aims to evaluate the efficacy and safety of oral tecovirimat therapy for patients with smallpox and monkeypox and to prepare a scheme for oral tecovirimat use in Japan.

METHODS AND ANALYSIS

This nationwide, multicentre, non-randomised, open-label, double-arm study will involve viral examination of the blood, throat swabs, urine and skin lesions, performed periodically. Participants will freely decide whether to participate in an administered group (supportive treatment plus oral tecovirimat) or a non-administered group (only supportive treatment). Tecovirimat will be administered for 14 days. To ensure that financial problems do not preclude participation in the study, the research fund will cover the cost of tecovirimat and basic hospitalisation fees. The primary endpoint is the percentage of patients with negative PCR results (cycle threshold value ≥40) for skin lesion specimens at 14 days after inclusion in the study. Secondary endpoints include mortality at 14 and 30 days, viral load in each sample, duration of fever and adverse events. The sample size is estimated to be 50 patients with monkeypox or smallpox.

ETHICS AND DISSEMINATION

Written informed consent will be obtained from all participants. This study was approved by the Certified Review Board of National Center for Global Health and Medicine and published in the Japan Registry of Clinical Trials. The results of this study will be published in peer-reviewed journals and/or in presentations at academic conferences.

TRIAL REGISTRATION NUMBER

jRCTs031220169.

Effectiveness of inactivated influenza and COVID-19 vaccines in hospitalized children in 2022/23 season in Japan - The first season of co-circulation of influenza and COVID-19

We have analyzed the inactivated vaccine effectiveness (VE)for preventing influenza hospitalization by test-negative design in the 2022/23 season. This is the first season of co-circulation of influenza and COVID-19, and a unique period because all inpatients received COVID-19 screening. Among 536 children hospitalized with fever, none were positive for both influenza and SARS-CoV-2. The adjusted VE for preventing influenza A for all children, the 6-12-year-old group, and those with underlying diseases was 34 % (95 ％CI, -16 %-61 %, n = 474), 76 % (95 ％ CI, 21 %-92 %, n = 81), and 92 % (95 ％ CI, 30 %-99 %, n = 86), respectively. Only 1 out of 35 hospitalized cases with COVID-19, and 42 out of 429 controls, had been immunized with COVID-19 vaccine. This is the first report showing influenza VE by age group in children in this limited season. We still recommend the inactivated influenza vaccine for children based on the significant VE in subgroup analysis.

Investigation of oral macrolide prescriptions in Japan using a retrospective claims database, 2013-2018

Macrolide usage in Japan exceeds that in Europe and the United States. Investigating the actual conditions in which macrolides are used is important for identifying further interventions for appropriate antimicrobial use; however, this situation has not been evaluated in Japan. Therefore, we aimed to clarify the number of macrolide prescriptions and their changes before and after implementation of the Antimicrobial Resistance (AMR) Action Plan. In addition, we also investigated the names of diseases for which macrolides have been prescribed and the number of days of prescription. A retrospective observational study was conducted using JMDC claims data from January 2013 to December 2018. The proportion of all oral antimicrobials and macrolides used during this period and the diseases for which macrolides were used in the 3 years before and after the AMR Action Plan were determined separately for acute (< 14 prescription days) and chronic (> 14 prescription days) diseases. The number of prescriptions for macrolides constituted approximately 30% of those for all oral antimicrobials; of these, clarithromycin accounted for approximately 60%. Most prescriptions for acute diseases were for common cold, whereas allergic and dermatological diseases were included among chronic diseases. The names of these illnesses did not change before and after the AMR Action Plan. Overall, these results indicate that appropriate macrolide use involves a review of their use for common cold along with appropriate evaluation of their long-term use for skin and allergic diseases. They also indicate the need for further fact-finding studies and ongoing AMR measures.

Decline in Antimicrobial Consumption and Stagnation in Reducing Disease Burden due to Antimicrobial Resistance in Japan

INTRODUCTION

Antimicrobial resistance (AMR) is a major global health threat. While antimicrobial consumption (AMC) in Japan substantially decreased after implementation of the AMR National Action Plan, the disease burden due to AMR seems to be unchanged. The main objective of this study is to examine the relationship between AMC and the disease burden due to AMR in Japan.

METHODS

We estimated the annual population-standardized AMC from 2015 to 2021 using defined daily doses (DDDs) per 1000 inhabitants per day (DIDs) and the disease burden due to bloodstream infections caused by nine major antimicrobial-resistant bacteria (AMR-BSIs) from 2015 to 2021 using disability-adjusted life years (DALYs). We then examined the correlation between AMC and DALYs using Spearman's rank correlation coefficient and cross-correlation function. Spearman's [Formula: see text] > 0.7 was considered to indicate a strong correlation.

RESULTS

The sales amounts of third-generation cephalosporins, fluoroquinolones, and macrolides were 3.82 DIDs, 2.71 DIDs, and 4.59 DIDs, respectively, in 2015, but 2.11, 1.48, and 2.72 in 2021. This corresponded to reductions of 44.8%, 45.4%, and 40.7% during the study period. DALYs due to AMR-BSIs were 164.7 per 100,000 population in 2015 but 195.2 per 100,000 in 2021. Spearman's rank correlation coefficients between AMC and DALYs were - 0.37 (total antibiotics), - 0.50 (oral antibiotics), - 0.43 (third-generation cephalosporins), - 0.5 (fluoroquin,olones) and - 0.5 (macrolides). No obvious cross-correlations were found.

CONCLUSIONS

Our results reveal that changes in AMC are not associated with DALYs caused by AMR-BSIs. AMR countermeasures besides efforts to reduce inappropriate AMC might be necessary to mitigate the disease burden due to AMR.

Clinical efficacy of remdesivir for COVID-19 in children: A propensity-score-matched analysis

Clinical efficacy of remdesivir in children with COVID-19 is unclear. This propensity-score-matched retrospective cohort study of children with COVID-19 showed that the rate of patients achieving defervescence on Day 4 was higher in the remdesivir group than in the non-remdesivir group, but was not statistically different (86.7% vs 73.3%, P = 0.333).

The estimated disease burden of COVID-19 in Japan from 2020 to 2021

BACKGROUND

To date, it is not fully understood to what extent COVID-19 has burdened society in Japan. This study aimed to estimate the total disease burden due to COVID-19 in Japan during 2020-2021.

METHODS

We stratify disease burden estimates by age group and present it as absolute Quality Adjusted Life Years (QALYs) lost and QALYs lost per 100,000 persons. The total estimated value of QALYs lost consists of (1) QALYs lost brought by deaths due to COVID-19, (2) QALYs lost brought by inpatient cases, (3) QALYs lost brought by outpatient cases, and (4) QALYs lost brought by long-COVID.

RESULTS

The total QALYs lost due to COVID-19 was estimated as 286,782 for two years, 114.0 QALYs per 100,000 population per year. 71.3% of them were explained by the burden derived from deaths. Probabilistic sensitivity analysis showed that the burden of outpatient cases was the most sensitive factor.

CONCLUSIONS

The large part of disease burden due to COVID-19 in Japan from the beginning of 2020 to the end of 2021 was derived from Wave 3, 4, and 5 and the proportion of QALYs lost due to morbidity in the total burden increased gradually. The estimated disease burden was smaller than that in other high-income countries. It will be our future challenge to take other indirect factors into consideration.

Association between SARS-CoV-2 anti-spike antibody titers and the development of post-COVID conditions: A retrospective observational study

The symptoms that persist after an acute coronavirus disease 2019 (COVID-19) are referred to as post- COVID conditions. Although the cause of post-COVID conditions remains unclear, the host immune response to SARS-CoV-2 may be involved. Hence, we aimed to investigate the effect of serum antibody titers against SARS-CoV-2 on the development of post-COVID conditions. We conducted a retrospective observational study of COVID-19-recovered individuals who attended the clinic at the National Center for Global Health and Medicine between January 2020 and April 2021. Serum SARS-CoV-2 anti-spike antibody titers were measured and a questionnaire survey was used to collect information on the presence of post-COVID conditions and demographic characteristics of the participants. Participants were then divided into two groups: high peak antibody titer group [≥ 0.759 OD450 value], and low peak antibody titer group [< 0.759 OD450 value] and compared their frequency of post-COVID conditions. Of 526 individuals attending the clinic, 457 (86.9%) responded to the questionnaire. We analyzed the data of 227 (49.7%) participants with measurements of serum antibody titers during the peak period. The incidence of depressed mood was significantly higher in the group with higher antibody titers (odds ratio: 2.34, 95% CI: 1.17-4.67, p = 0.016). There was no significant difference in the frequency of the remaining symptoms between the two groups. Among post-COVID conditions, the depressed mood was more frequent in the group with high serum antibody titers which suggests a difference in pathogenesis between depressive mood and other post-COVID conditions that requires further investigation.

Treatment with tecovirimat of the first two cases of monkeypox in Japan

Outbreaks of monkeypox in Europe and North America have been reported since May 2022. At the end of July, we encountered the first two cases of monkeypox diagnosed in Japan. Case 1 was a white man who traveled to Spain where he had sexual intercourse with men. He presented to our hospital with fever, rash, and tiredness, and was diagnosed with monkeypox based on positive PCR test results from the skin lesions. He was admitted to our hospital, received tecovirimat 600 mg twice daily, and was discharged on day 15. Case 2 involved a Japanese man who visited us because of fatigue, muscle pain, headache, and oral ulcers. He was living in New York and traveled to Japan one day before presentation. He had experienced sexual intercourse with men four times during the previous month. The patient was diagnosed with monkeypox based on positive PCR results from the blood. He was admitted to our hospital, received tecovirimat 600 mg twice daily, and was discharged on day 14. These were the first two cases of monkeypox diagnosed in Japan. Based on their history and epidemiology, the viruses seem to have been imported from Europe and North America, respectively. After initiation of tecovirimat, both patients showed mild symptoms and immediate disappearance of viral DNA. The second case was notable for being diagnosed without skin rash. Our report suggests that tecovirimat could decrease the viral load rapidly, and that our prompt diagnosis contributed to the prevention of a monkeypox outbreak in Japan.

Characteristics of hospitalized COVID-19 patients with other respiratory pathogens identified by rapid diagnostic test

Rapid diagnostic tests (RDTs) significantly impact disease treatment strategy. In Japan, information on the use of RDTs for patients with COVID-19 is limited. Here, we aimed to investigate the RDT implementation rate, pathogen detection rate, and clinical characteristics of patients positive for other pathogens by using COVIREGI-JP, a national registry of hospitalized patients with COVID-19. A total of 42,309 COVID-19 patients were included. For immunochromatographic testing, influenza was the most common (n = 2881 [6.8%]), followed by Mycoplasma pneumoniae (n = 2129 [5%]) and group A streptococcus (GAS) (n = 372 [0.9%]). Urine antigen testing was performed for 5524 (13.1%) patients for S. pneumoniae and for 5326 patients (12.6%) for L. pneumophila. The completion rate of M. pneumonia loop-mediated isothermal amplification (LAMP) testing was low (n = 97 [0.2%]). FilmArray RP was performed in 372 (0.9%) patients; 1.2% (36/2881) of patients were positive for influenza, 0.9% (2/223) for the respiratory syncytial virus (RSV), 9.6% (205/2129) for M. pneumoniae, and 7.3% (27/372) for GAS. The positivity rate for urine antigen testing was 3.3% (183/5524) for S. pneumoniae and 0.2% (13/5326) for L. pneumophila. The positivity rate for LAMP test was 5.2% (5/97) for M. pneumoniae. Five of 372 patients (1.3%) had positive FilmArray RP, with human enterovirus being the most frequently detected (1.3%, 5/372). The characteristics of patients with and without RDTs submission and positive and negative results differed for each pathogen. RDTs remain an important diagnostic tool in patients with COVID-19 in whom coinfection with other pathogens needs to be tested based on clinical evaluation.

Regional trends in the use of steroids and favipiravir for COVID-19 treatment

BACKGROUND

Infectious diseases are treated based on clinical guidelines, which usually require a large amount of data and time to formulate. Therefore, various treatments are tried and used in the early stages of epidemics of emerging and reemerging infectious diseases. In this study, we focused on two drugs for coronavirus disease 2019 (COVID-19) treatment, i.e., steroids and favipiravir, and analyzed the changes in treatment trends by region.

METHODS

This was a retrospective study of cases from the COVID-19 Registry Japan. The proportion of patients who received steroids and favipiravir was calculated on a monthly and pandemic wave basis, and the trend of drug administration by region was estimated using logistic curves.

RESULTS

The effect of wave on steroid administration was as high as 2.75 [2.60, 2.90], indicating a rapid increase in the proportion of steroid administration. The odds ratios for Hokuriku and Hokkaido were 0.49 [0.35, 0.68] and 0.55 [0.43, 0.71], respectively, indicating that steroids were less likely administered in these regions. For favipiravir, the effect of timing was 0.43 [0.41, 0.46], denoting a decreasing trend. On the other hand, the odds ratio was very high in some regions, such as Hokkaido (6.66 [5.24, 8.48]), indicating that the administration trend varied by region.

CONCLUSIONS

The increase in the proportion of steroid use showed the same trend nationwide, although the rate of increase differed, confirming that the use of drugs with proven efficacy was spreading rapidly and that effective treatment was available nationwide. However, the results suggest that drugs such as favipiravir, which were initially expected to be effective, may continue to be administered. Registry studies include larger populations than clinical trials and enable real-time monitoring of medication status and trends. Further use of registry studies for treatment standardization is expected in the future.

Effects of population age structure on parenteral antimicrobial use estimations

Antimicrobial use (AMU) is conventionally reported as unadjusted defined daily doses (DDDs) or population-adjusted DDDs per 1000 inhabitants per day (DID). DID is frequently used to monitor national AMU trends, this metric does not intrinsically take temporal changes in population age structure into account. We examined the effects of population age structure on DID estimates of parenteral AMU in Japan, and predicted future trends in DDDs based on population projections. Parenteral AMU data from 2013 to 2018 were acquired from a national claims database. We assessed temporal trends in parenteral AMU by age group (children aged < 15 years, working-age persons aged 15-64 years, and older persons aged ≥ 65 years) using both DID and DDDs. In addition, we modeled DDD predictions based on age-specific population projections from 2019 to 2030. DID values for older persons were 8.08-10.15 times and 5.43-5.63 times higher than in children and working-age persons, respectively. DID was stable, but DDDs increased in older persons. The prediction models showed that DDDs will continue to increase until 2030 if DID remains steady or decreases. DID estimates were skewed by the older population. More rigorous antimicrobial stewardship efforts targeting geriatric care are needed to counter the aging-associated increase in AMU.

We Should Pay More Attention to Sex Differences to Predict the Risk of Severe COVID-19: Men Have the Same Risk of Worse Prognosis as Women More Than 10 Years Older

BACKGROUND

Prioritization for novel coronavirus disease 2019 (COVID-19)-related health policies usually considers age and certain other characteristics, but sex is rarely included, despite the higher risk of severe disease in men. The aim of this study was to compare the impact of sex and age on the severity of COVID-19 by estimating the age difference in years for which the risk for men versus women is the same.

METHODS

We analyzed 23,414 Japanese COVID-19 inpatients aged 20-89 years (13,360 men and 10,054 women). We graded the severity of COVID-19 (0 to 5) according to the most intensive treatment required during hospitalization. The risk of grade 2/3/4/5 (non-invasive positive pressure ventilation/invasive mechanical ventilation/extracorporeal membrane oxygenation/death), grade 3/4/5, and separately grade 5 was analyzed using a multiple logistic regression model.

RESULTS

The odds ratio (OR) of grades 2/3/4/5, 3/4/5 (primary outcome), and 5 for men relative to women was 2.76 (95% CI, 2.44-3.12), 2.78 (95% CI, 2.42-3.19), and 2.60 (95% CI, 2.23-3.03), respectively, after adjustment for age and date of admission. These risks for men were equivalent to those for women 14.1 (95% CI, 12.3-15.8), 11.2 (95% CI, 9.7-12.8), and 7.5 (95% CI, 6.3-8.7) years older, respectively.

CONCLUSION

The risks of worse COVID-19 prognosis (grades 3/4/5) in men were equivalent to those of women 11.2 years older. Reanalyzing data extracted from four previous studies also revealed a large impact of sex difference on the severity of COVID-19. We should pay more attention to sex differences to predict the risk of COVID-19 severity and to formulate public health policy accordingly.

Comparing the effects of antimicrobial stewardship at primary emergency centers

BACKGROUND

Antimicrobial prescription rates tend to be high in outpatient settings and Primary Emergency Medical Centers (PECs) in Japan encounter difficulties in implementing antimicrobial stewardship programs (ASPs). While a nudge-based ASP publishing monthly newsletters reduces inappropriate prescription of oral third-generation cephalosporins (3GCs), which requires considerable effort. Therefore, developing more preferable ASP models in PECs is essential.

METHODS

We conducted a three-center, retrospective observational study. Himeji City Emergency Medical Center (Site A) introduced a facility-specific guideline for antimicrobial stewardship with reference to national guidelines. The Kobe Children's Primary Emergency Medical Center (Site B) provided the results of monitoring antibiotics prescription in a monthly newsletter. The Hanshin-Kita Children's First-Aid Center (Site C) did not perform a specific ASP. Prescription rates for 3GCs were categorized into pre- and post-intervention and compared using Poisson regression analysis. The difference-in-difference method was used to assess the effect of these interventions.

RESULTS

The numbers of patients pre- and post- intervention were 177,126 and 91,251, respectively. The 3GCs prescription rate at Site A, Site B, and Site C decreased from 6.7%, 4.2%, and 6.1% in 2016 to 2.3%, 1.0%, and 2.0% in 2019, respectively. Site B had a greater reduction than Site A and Site C (relative risk [RR] 0.71 [95% confidence interval (CI): 0.62-0.82]; p < 0.001, RR 0.71, [95% CI: 0.62-0.81]; p < 0.001). There was no significant difference between Site A and Site C (RR 1.00 [95% CI 0.88-1.13]; p = 0.963).

CONCLUSION

A facility-specific guideline was less effective than a nudge-based ASP for decreasing oral 3GC prescriptions in PECs.

Does the experience of the first assistant affect organ injuries in laparoscopic hysterectomy for benign diseases?

PURPOSE

This study sought to explore whether the experience level of the first assistant surgeon influences perioperative organ injuries (ureteral, bladder, and intestinal injuries) in patients undergoing total laparoscopic hysterectomy (TLH) for benign diseases. We defined an experienced surgeon as a surgeon certified by the Skill Qualification Committee of the Japan Society of Gynecologic and Obstetric Endoscopy and Minimally Invasive Therapy or a surgeon with equivalent surgical skills.

METHODS

We reviewed our surgical registry database of TLH for benign indications between 2014 and 2020 and only selected cases performed by an experienced primary surgeon. Patients were divided into two groups based on the experience level of the first assistant. Inverse probability of treatment weighting by propensity score, which was adjusted for patient and procedure characteristics, was used to examine differences in perioperative organ injuries according to the experience level of the first assistant.

RESULTS

Among 1682 patients who underwent TLH, 18 organ injuries were found (0.83%). In the propensity score inverse probability of treatment weighting models, less experience of the first assistant had no significant impact on the occurrence of perioperative organ injuries (p = 0.348).

CONCLUSION

In TLH for benign indications at our hospital, given an experienced primary surgeon, the inclusion of a less experienced first assistant does not negatively affect the occurrence of perioperative organ injuries.

Preserved SARS-CoV-2 neutralizing IgG activity of in-house manufactured COVID-19 convalescent plasma

PURPOSE

In the current study, we aimed to evaluate the neutralizing IgG activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as well as the coagulation factors of convalescent plasmas which we manufactured in-house without a fast-freezing technique.

METHODS

We collected plasmas from eligible participants who had confirmed certain titers of neutralizing antibodies. The plasmas were frozen and stored in the ordinary biofreezer without a fast-freezing function. The purified-IgG neutralizing activity of 20 samples from 19 participants and the coagulation factors of 49 samples from 40 participants were evaluated before and after freezing.

RESULTS

Purified-IgG maintained its neutralizing activities, with the median 50 % inhibitory concentration (IC50) of 10.11 mg/ml (IQR 6.53-18.19) before freezing and 8.90 m g/ml (IQR 6.92-28.27) after thawing (p = 0.956). On the contrary, fibrinogen and factor Ⅷ decreased significantly after freezing and thawing in our environment. No significant temperature deviation was observed during the storage period.

CONCLUSION

Neutralizing IgG activity, which largely contributes to the antiviral activity of convalescent plasma, did not change through our in-house manufacturing, without fastfreezing and storage conditions for more than 200 days. Ordinary freezers without the fast-freezing function are suitable enough to manufacture and store convalescent plasmas. Hospitals or facilities without specified resources could easily collect and store convalescent plasmas in case of upcoming emerging or re-emerging infectious diseases on-demand with appropriate neutralizing antibody levels measurements.

1147. Regional Trends in Favipiravir and Steroid Use in the Treatment of COVID-19

Background

Two years have passed since the global outbreak of COVID-19 began. Vaccines and many therapeutic agents have now been developed, and treatment is being conducted in accordance with guidelines. In general, it takes a long time for guidelines to be established, as a large amount of clinical data is required. Therefore, in the early and middle stages of an epidemic, treatment is often based on experience at individual centers. This study focuses on two drugs, Favipiravir and Steroid, and investigates how trends in drug use changed in different regions.

Methods

We compared the proportion of drug administered patients in the COVID-19 Registry Japan (COVIREGI-JP). Data from four COVID-19 epidemic waves, from January 2020 to June 2021, were included for the analysis. To compare regional trends, 10 categories were used based on existing classifications. In addition, Tokyo and Osaka were accounted for separately, for a total of 12 regions. Severity of each case was divided into mild, moderate 1, moderate 2 and severe based on the condition on admission, and the proportion of Favipiravir or Steroid administered cases was calculated for moderate 2 and severe cases.

Results

Favipiravir was administered to more than 50-100% of patients in the first wave. Thereafter, it declined nationwide, with sharp falls in Tokyo (34.9%, 16.5% and 4.3%) and Osaka (48.8%, 41.8% and 8.0%). In Hokkaido, on the other hand, 82.4%, 53.7% and 59.8% of the cases still continued to receive Favipiravir.

In the first wave, Steroid was administered to 20-40% of cases. The proportion gradually increased, with 50-80% in the second wave, and 85.5% in Tokyo, 93.4% in Osaka and 90.2% in Hokkaido in the fourth wave, the majority of cases.

Changes over time in the proportions of cases treated with Favipiravir and Steroid in each region.

The top four and middle four panels show the proportion of cases treated with Favipiravir and Steroid, respectively. The lower epi-curve shows the number of COVID-19 cases in Japan.

Conclusion

We confirmed that the more effective treatment was rapidly spreading throughout the country. More information is available in areas with a large number of cases, such as Tokyo and Osaka, and in facilities that see a large number of cases. On the other hand, it may be difficult for smaller facilities or facilities that do not see many COVID-19 cases. Information from registry studies would be useful in making more effective treatments available earlier and more widely. We believe that further use of COVIREGI-JP would promote standardization of treatment.

Disclosures

All Authors: No reported disclosures.

2245. Urinary tract infections in the elderly population in Japan; long hospital stay, high medical costs, and decline in the activities of daily living scores

Background

Japan has one of the most aging societies in the world. Urinary tract infection (UTI) is a common disease in the elderly, and the incidence of hospitalization owing to UTI is increasing with the aging population. Here, we examined the length of hospital stay, differences in the Barthel index (BI), activities of daily living score (ADLs) at admission and discharge, and medical costs of UTI in elderly patients.

Methods

We retrospectively included hospitalized UTI patients in our center between January 1, 2013 and March 31, 2019. The inclusion criteria were as follows: (1) urine culture positive for Escherichia coli (over 104 colony forming units/mL) within 48 h of admission, and (2) the presence of at least one of the following: fever ≥ 38°C, costovertebral angle tenderness, suprapubic tenderness, and dysuria at the time of admission. We classified the enrolled patients into four groups according to age: young adults (20–64 years), pre-old (65–74 years), old (75–84 years), and super-old (≥ 85 years). Patient characteristics were compared across groups using the Mann–Whitney U test, Fisher’s exact test, and Kruskal-Wallis test. The Bonferroni corrected P &lt; 0.05 was considered statistically significant.

Results

This study enrolled 393 cases, including 112 (28.4%) young adults, 72 (18.3%) pre-old, 130 (33.2%) old, and 79 (20.1%) super-old. The lengths of hospital stay were 10.8, 17.9, 17.2, and 21.6 days in young adults, pre-old, old, and super-old, respectively (P &lt; 0.05). Differences in the BI were 1.2, 4.2, 5.2, and 5.2 in young adults, pre-old, old, and super-old, respectively (P &lt; 0.05). However, no significant differences in these values were noted among the pre-old, old, and super-old groups. The medical costs were 6,054, 8,310, 10,129, and 12,577-USD (1USD = 128 yen) in young adults, pre-old, old, and super-old, respectively (P &lt; 0.05). Nevertheless, a comparison of the medical costs per day showed no significant differences among the groups.

Conclusion

UTI in elderly patients were associated with ADLs decline, longer hospital stays, and higher medical costs than those in younger patients; however, no significant differences were found among those aged ≥ 65 years.

Disclosures

Sho Saito, MD, PhD, DAIICHI SANKYO: Grant/Research Support|EVEC: Grant/Research Support|EVEC: Patents obtained through collaborative research|SHIONOGI: Grant/Research Support|Takeda: Advisor/Consultant.

Comparison of clinical characteristics of COVID-19 in pregnant women between the Delta and Omicron variants of concern predominant periods

Background

Information regarding effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant strains on clinical manifestations and outcomes of coronavirus disease 2019 (COVID-19) in pregnant women is limited.

Methods

A retrospective observational study was conducted using the data from the nationwide COVID-19 registry in Japan. We identified pregnant patients with symptomatic COVID-19 hospitalized during the study period. The Delta and Omicron variants of concern (VOC) predominant periods were defined as August 1 to December 31, 2021 and January 1 to May 31, 2022, respectively. Clinical characteristics were compared between the patients in the Delta and Omicron VOC periods. In addition, logistic regression analysis was performed to identify risk factors for developing moderate-to-severe COVID-19.

Results

During the study period, 310 symptomatic COVID-19 cases of pregnant women were identified; 111 and 199 patients were hospitalized during the Delta and Omicron VOC periods, respectively. Runny nose and sore throat were more common, and fatigue, dysgeusia, and olfactory dysfunction were less common manifestations observed in the Omicron VOC period. In the multivariable logistic regression analysis, onset during the later stage of pregnancy (OR: 2.08 [1.24–3.71]) and onset during the Delta VOC period (OR: 2.25 [1.08–4.90]) were independently associated with moderate-to-severe COVID-19, whereas two doses of SARS-CoV-2 vaccine were protective against developing moderate-to-severe COVID-19 (OR: 0.34 [0.13–0.84]).

Conclusions

Clinical manifestations of COVID-19 in pregnant women differed between the Delta and Omicron VOC periods. SARS-CoV-2 vaccination was still effective in preventing severe COVID-19 throughout the Delta and Omicron VOC periods.

Evaluation of the representativeness of data in the COVID-19 Registry Japan during the first six waves of the epidemic

The COVID-19 Registry Japan (COVIREGI-JP), a registry of patients hospitalized with coronavirus disease (COVID-19), contains the largest national COVID-19 inpatient population. Since COVIREGI-JP invites voluntary participation by facilities, selection bias is inevitable. The current study examined the representativeness of COVIREGI-JP data in comparison to open-source national data. The number of infections and deaths among hospitalized COVID-19 patients in COVIREGI-JP were compared to those in national data recorded during the six waves of the COVID-19 epidemic until March 6, 2022. During the period studied, patients in COVIREGI-JP represented 1% of the total COVID-19 cases according to national data; the proportion was high during the first wave (32.7%) and tended to decrease, especially after the fourth wave. The overall proportion of patients from each region varied from 0.8% to 2.5%, but case fatality rates in COVIREGI-JP tended to be higher than those in the national data, with the exception of a few waves, in several regions. The difference was smallest during the first wave. Although COVIREGI-JP consistently registered cases from all regions of the country, the proportion tended to decline after the beginning of the epidemic. Given the epidemiological persistence and the ever-changing epidemiology of COVID-19, continued case registration and data utilization in COVIREGI-JP is desirable, although selection bias in COVIREGI-JP registration of cases should be carefully interpreted.

Impact of long-COVID on health-related quality of life in Japanese COVID-19 patients

Background

The empirical basis for a quantitative assessment of the disease burden imposed by long-COVID is currently scant. We aimed to inform the disease burden caused by long-COVID in Japan.

Methods

We conducted a cross sectional self-report questionnaire survey. The questionnaire was mailed to 526 eligible patients, who were recovered from acute COVID-19 in April 2021. Answers were classified into two groups; participants who have no symptom and those who have any ongoing prolonged symptoms that lasted longer than four weeks at the time of the survey. We estimated the average treatment effect (ATE) of ongoing prolonged symptoms on EQ-VAS and EQ-5D-3L questionnaire using inverse probability weighting. In addition to symptom prolongation, we investigated whether other factors (including demography, lifestyle, and acute severity) were associated with low EQ-VAS and EQ-5D-3L values, by multivariable linear regression.

Results

349 participants reported no symptoms and 108 reported any symptoms at the time of the survey. The participants who reported any symptoms showed a lower average value on the EQ-VAS (69.9 vs 82.8, respectively) and on the EQ-5D-3L (0.85 vs 0.96, respectively) than those reporting no symptoms considering the ATE of ongoing prolonged symptoms. The ATE of ongoing prolonged symptoms on EQ-VAS was − 12.9 [95% CI − 15.9 to − 9.8], and on the EQ-5D-3L it was − 0.11 [95% CI − 0.13 to − 0.09], implying prolonged symptoms have a negative impact on patients’ EQ-VAS and EQ-5D-3L score. In multivariable linear regression, only having prolonged symptoms was associated with lower scores (− 11.7 [95% CI − 15.0 to − 8.5] for EQ-VAS and − 0.10 [95% CI − 0.13 to − 0.08] for EQ-5D-3L).

Conclusions

Due to their long duration, long-COVID symptoms represent a substantial disease burden expressed in impact on health-related quality of life.

Post COVID-19 condition of the Omicron variant of SARS-CoV-2

Objectives

To investigate the prevalence of post coronavirus disease (COVID-19) condition of the Omicron variant in comparison to other strains.

Study design

A single-center cross-sectional study.

Methods

Patients who recovered from Omicron COVID-19 infection (Omicron group) were interviewed via telephone, and patients infected with other strains (control group) were surveyed via a self-reporting questionnaire. Data on patients’ characteristics, information regarding the acute-phase COVID-19, as well as presence and duration of COVID-19-related symptoms were obtained. Post COVID-19 condition in this study was defined as a symptom that lasted for at least 2 months, within 3 months of COVID-19 onset. We investigated and compared the prevalence of post COVID-19 condition in both groups after performing propensity score matching.

Results

We conducted interviews for 53 out of 128 patients with Omicron and obtained 502 responses in the control group. After matching cases with controls, 18 patients from both groups had improved covariate balance of the factors: older adult, female sex, obesity, and vaccination status. There were no significant differences in the prevalence of each post COVID-19 condition between the two groups. The number of patients with at least one post COVID-19 condition in the Omicron and control groups were 1 (5.6%) and 10 (55.6%) (p = 0.003), respectively.

Conclusions

The prevalence of post Omicron COVID-19 conditions was less than that of the other strains. Further research with a larger sample size is needed to investigate the precise epidemiology of post COVID-19 condition of Omicron, and its impact on health-related quality of life and social productivity.

Clinical characteristics of COVID-19 in hospitalized children during the Omicron variant predominant period

Introduction

Information regarding the clinical manifestations and outcomes of coronavirus disease 2019 (COVID-19) in children under the Omicron variant predominant period is still limited.

Methods

A nationwide retrospective cohort study was conducted. Pediatric COVID-19 patients (<18 years of age) hospitalized between August 1, 2021 and March 31, 2022 were enrolled. Epidemiological and clinical characteristics between the Delta variant predominant period (August 1 to December 31, 2021) and the Omicron variant predominant period (January 1 to March 31, 2022) were compared.

Results

During the study period, 458 cases in the Delta predominant period and 389 cases in the Omicron predominant period were identified. Median age was younger (6.0 vs. 8.0 years, P = 0.004) and underlying diseases were more common (n = 65, 16.7% vs. n = 53, 11.6%) in the Omicron predominant period than those in the Delta variant predominant era. For clinical manifestations, fever ≥38.0 °C at 2 to <13 years old, sore throat at ≥ 13 years, and seizures at 2 to <13 years old were more commonly observed, and dysgeusia and olfactory dysfunction at ≥ 6 years old were less commonly observed in the Omicron variant predominant period. The number of patients requiring noninvasive oxygen support was higher in the Omicron predominant period than that in the Delta predominant period; however, intensive care unit admission rates were similar and no patients died in both periods.

Conclusions

In the Omicron variant predominant period, more pediatric COVID-19 patients experienced fever and seizures, although the overall outcomes were still favorable.

Predictive model of risk factors of High Flow Nasal Cannula using machine learning in COVID-19

With the rapid increase in the number of COVID-19 patients in Japan, the number of patients receiving oxygen at home has also increased rapidly, and some of these patients have died. An efficient approach to identify high-risk patients with slowly progressing and rapidly worsening COVID-19, and to avoid missing the timing of therapeutic intervention will improve patient prognosis and prevent medical complications. Patients admitted to medical institutions in Japan from November 14, 2020 to April 11, 2021 and registered in the COVID-19 Registry Japan were included. Risk factors for patients with High Flow Nasal Cannula invasive respiratory management or higher were comprehensively explored using machine learning. Age-specific cohorts were created, and severity prediction was performed for the patient surge period. We were able to obtain a model that was able to predict severe disease with a sensitivity of 57% when the specificity was set at 90% for those aged 40–59 years, and with a specificity of 50% and 43% when the sensitivity was set at 90% for those aged 60–79 years and 80 years and older, respectively. We were able to identify lactate dehydrogenase level (LDH) as an important factor in predicting the severity of illness in all age groups. Using machine learning, we were able to identify risk factors with high accuracy, and predict the severity of the disease. We plan to develop a tool that will be useful in determining the indications for hospitalisation for patients undergoing home care and early hospitalisation.

Predictors of silent hypoxia in hospitalized patients with COVID-19 in Japan

INTRODUCTION

Silent hypoxia (SH) is common in patients with coronavirus disease (COVID-19) in Japan and other countries. Early identification of SH is important as more treatment options for COVID-19 have become available. This study aimed to identify predictors of SH using a nationwide COVID-19 registry of hospitalized patients.

METHODS

Adult patients who were admitted to hospital with COVID-19 between January 2020 and June 2021 and who were hypoxic on admission (SpO₂: 70-93%), not transferred from another facility, and who did not have disturbance of consciousness, confusion, or dementia, were included. SH was defined as hypoxia in the absence of shortness of breath/dyspnea upon admission. Predictors of SH were identified using univariable and multivariable logistic regression.

RESULTS

The study included 1904 patients, of whom 990 (52%) satisfied the criteria for SH. Compared to patients without SH, patients with SH were older, more likely to be female, and had a slightly higher SpO₂ on admission. Compared to patients without SH, patients with SH had a lower prevalence of chronic lung disease (CLD) other than chronic obstructive pulmonary disease (COPD), asthma, and obesity. Multivariable analysis revealed that the independent predictors of SH were older age, a shorter interval from symptom onset to admission, higher SpO₂, and an absence of CLD or COPD.

CONCLUSIONS

The absence of underlying lung disease and older age were important predictors of SH. The results of this study, which is the largest such study reported to date in Japan, may help clarify the mechanism of SH.

Factors associated with development and persistence of post-COVID conditions: A cross-sectional study

INTRODUCTION

The post-COVID condition has become a social concern. Although the patient characteristics associated with the development of this condition are partially known, those associated with its persistence have not been identified.

METHODS

We conducted a cross-sectional questionnaire-based survey among patients who had recovered from COVID-19 and visited the National Center for Global Health and Medicine between February 2021 and March 2021. Demographic and clinical data, and data regarding the presence and duration of post-COVID conditions were obtained. We identified factors associated with the development and persistence of post-COVID conditions using multivariate logistic and linear regression analyses, respectively.

RESULTS

We analyzed 457 of 526 responses (response rate, 86.9%). The median patient age was 47 years. Of these, 378 patients (84.4%) had mild disease in the acute phase. The number of patients with symptoms at 6 and 12 months after onset or diagnosis was 120 (26.3%) and 40 (8.8%), respectively. Women were at risk of developing fatigue (odds ratio [OR]: 2.03, 95% confidence interval [CI]: 1.31-3.14), dysosmia (OR: 1.91, 95%CI: 1.24-2.93), dysgeusia (OR: 1.56, 95%CI: 1.02-2.39), hair loss (OR: 3.00, 95%CI: 1.77-5.09), and persistence of any symptoms (coefficient: 38.0, 95%CI: 13.3-62.8). Younger age and low body mass index were factors for developing dysosmia (OR: 0.96, 95%CI: 0.94-0.98 and OR: 0.94, 95%CI: 0.89-0.99, respectively) and dysgeusia (OR: 0.98, 95%CI: 0.96-1.00 and OR: 0.93, 95%CI: 0.88-0.98, respectively).

CONCLUSION

We identified factors involved in the development and persistence of post-COVID conditions. Many patients, even those with mild conditions, experience long-term residual symptoms.

Long COVID: current status in Japan and knowledge about its molecular background

Even after recovering from coronavirus disease 2019 (COVID-19), patients can experience prolonged complaints, referred to as "long COVID". Similar to reports in Caucasians, a follow-up study in Japan revealed that fatigue, dyspnea, cough, anosmia/dysgeusia, and dyssomnia are common symptoms. Although the precise mode of long COVID remains elusive, multiple etiologies such as direct organ damage by infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), autoimmunity, prolonged inflammatory reactions, and psychiatric impairment seem to be involved. Notably, SARS-CoV-2 is neurotropic, and viral RNA and proteins are continuously detectable in multiple organs, including the brain. Viral proteins exert a number of different toxic effects on cells, suggesting that persistent infection is a key element for understanding long COVID. Here, we first reviewed the current status of long COVID in Japan, and then summarized literature that help us understand the molecular background of the symptoms. Finally, we discuss the feasibility of vaccination as a treatment for patients with long COVID.

The first eleven cases of SARS-CoV-2 Omicron variant infection in Japan: A focus on viral dynamics

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant has spread rapidly worldwide. We report the clinical characteristics and threshold cycle (Ct) values of the first 11 patients infected with the SARS-CoV-2 Omicron variant in Japan. All patients were younger returnees from abroad; 10 patients had received two doses of vaccine. Estimated Ct values for the 11 patients were 6.0 (95% confidence interval [CI] 4.2-7.3) days for > 30, 10.6 (95% CI 9.5-11.9) days for > 35, 15.1 (95% CI 13.6-17.6) days for > 40, and 19.7 (95% CI 17.3- 23.7) days for > 45. Our results provide important insights for indicators of infection control.

Effectiveness of Favipiravir on Nonsevere, Early-Stage COVID-19 in Japan: A Large Observational Study Using the COVID-19 Registry Japan

Introduction

Several randomized controlled trials have compared the effectiveness of favipiravir with that of placebo. However, evidence regarding its effect on nonsevere, early-stage coronavirus disease 2019 (COVID-19) remains insufficient.

Methods

We used the COVID-19 Registry Japan, a nationwide registry of inpatients with COVID-19, for evaluating the effectiveness of favipiravir on patients with nonsevere, early-stage COVID-19. Eligible patients, who did not need supplementary oxygen therapy at admission, were classified according to two regimens (starting favipiravir therapy within 4 days from admission vs. no favipiravir during hospitalization) and were then compared using a three-step method (cloning, censoring, and weighting). The primary outcome was supplementary oxygen requirement during hospitalization, and the secondary outcomes were the need for invasive mechanical ventilation or extracorporeal membrane oxygenation (IMV/ECMO) and overall mortality at 30 days.

Results

A total of 7654 cases were analyzed. The “start favipiravir” regimen did not show substantial differences in the primary outcome [hazard ratio 0.825, 95% confidence interval (CI) 0.657–1.04, p = 0.098] and both of the secondary outcomes [need for IMV/ECMO and overall 30-day mortality, hazard ratio 1.02 (95% CI 0.649–1.60) and 0.869 (95% CI 0.519–1.46), p = 0.929 and 0.594, respectively].

Conclusions

In this large cohort from a COVID-19 registry, favipiravir was not associated with a positive effect on the clinical outcome on patients with nonsevere, early-stage COVID-19, suggesting that it is not an essential drug for COVID-19 treatment.