Rapid response to a coronavirus disease 2019 (COVID-19) outbreak in a psychiatry hospital—Kanazawa City, Japan, March to April 2020

A coronavirus disease 2019 (COVID-19) outbreak in a psychiatry hospital revealed specific challenges in its response such as difficulty in isolation, transfer, and identification of close contacts, suboptimal infection control practices, and shortage of personal protective equipment, which were overcome by support from the public health center and a neighboring university hospital.

Association of severe COVID-19 outcomes with radiological scoring and cardiomegaly: findings from the COVID-19 inpatients database, Japan.

PURPOSE: We aimed to characterize novel coronavirus infections based on imaging [chest X-ray and chest computed tomography (CT)] at the time of admission. MATERIALS AND METHODS: We extracted data from 396 patients with laboratory-confirmed COVID-19 who were managed at 68 hospitals in Japan from January 25 to September 2, 2020. Case patients were categorized as severe (death or treatment with invasive ventilation during hospitalization) and non-severe groups. The imaging findings of the groups were compared by calculating odds ratios (ORs) and 95% confidence intervals (95% CIs), adjusted for sex, age, and hospital size (and radiographic patient positioning for cardiomegaly). Chest X-ray and CT scores ranged from 0 to 72 and 0 to 20, respectively. Optimal cut-off values for these scores were determined by a receiver-operating characteristic (ROC) curve analysis. RESULTS: The median age of the 396 patients was 48 years (interquartile range 28-65) and 211 (53.3%) patients were male. Thirty-two severe cases were compared to 364 non-severe cases. At the time of admission, abnormal lesions on chest X-ray and CT were mainly observed in the lower zone/lobe. Among severe cases, abnormal lesions were also seen in the upper zone/lobe. After adjustment, the total chest X-ray and CT score values showed a dose-dependent association with severe disease. For chest X-ray scores, the area under the ROC curve (AUC) was 0.91 (95% CI = 0.86-0.97) and an optimal cut-off value of 9 points predicted severe disease with 83.3% sensitivity and 84.7% specificity. For chest CT scores, the AUC was 0.94 (95% CI = 0.89-0.98) and an optimal cut-off value of 11 points predicted severe disease with 90.9% sensitivity and 82.2% specificity. Cardiomegaly was strongly associated with severe disease [adjusted OR = 24.6 (95% CI = 3.7-166.0)]. CONCLUSION: Chest CT and X-ray scores and the identification of cardiomegaly could be useful for classifying severe COVID-19 on admission.

Rapid response to a coronavirus disease 2019 (COVID-19) outbreak in a psychiatry hospital-Kanazawa City, Japan, March to April 2020.

A coronavirus disease 2019 (COVID-19) outbreak in a psychiatry hospital revealed specific challenges in its response such as difficulty in isolation, transfer, and identification of close contacts, suboptimal infection control practices, and shortage of personal protective equipment, which were overcome by support from the public health center and a neighboring university hospital.

Singing Is a Risk Factor for Severe Acute Respiratory Syndrome Coronavirus 2 Infection: A Case-Control Study of Karaoke-Related Coronavirus Disease 2019 Outbreaks in 2 Cities in Hokkaido, Japan, Linked by Whole Genome Analysis.

Background: Singing in an indoor space may increase the risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We conducted a case-control study of karaoke-related coronavirus disease 2019 (COVID-19) outbreaks to reveal the risk factors for SARS-CoV-2 infection among individuals who participate in karaoke. Methods: Cases were defined as people who enjoyed karaoke at a bar and who tested positive for SARS-CoV-2 by reverse-transcription polymerase chain reaction between 16 May and 3 July 2020. Controls were defined as people who enjoyed karaoke at the same bar during the same period as the cases and tested negative. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. ORs of key variables adjusted for each other were also estimated (aOR). Results: We identified 81 cases, the majority of whom were active elderly individuals (median age, 75 years). Six cases died (case fatality ratio, 7%). Among the cases, 68 (84%) were guests, 18 of whom had visited ≧2 karaoke bars. A genome analysis conducted in 30 cases showed 6 types of isolates within 4 single-nucleotide variation difference. The case-control study revealed that singing (aOR, 11.0 [95% CI, 1.2-101.0]), not wearing a mask (aOR, 3.7 [95% CI, 1.2-11.2]), and additional hour spent per visit (aOR, 1.7 [95% CI, 1.1-2.7]) were associated with COVID-19 infection. Conclusions: A karaoke-related COVID-19 outbreak that occurred in 2 different cities was confirmed by the results of genome analysis. Singing in less-ventilated, indoor and crowded environments increases the risk of acquiring SARS-CoV-2 infection. Wearing a mask and staying for only a short time can reduce the risk of infection during karaoke.

Singing Is a Risk Factor for SARS-CoV-2 Infection: A Case-control Study of Karaoke-related COVID-19 Outbreaks in Two Cities in Hokkaido, Japan, Linked by Whole Genome Analysis

Background Singing in an indoor space may increase the risk of SARS-CoV-2 infection. We conducted a case-control study of karaoke-related COVID-19 outbreaks to reveal the risk factors for SARS-CoV-2 infection among individuals who participate in karaoke. Methods Cases were defined as people who enjoyed karaoke at a bar and who tested positive for SARS-CoV-2 by RT-PCR between May 16 and July 3, 2020. Controls were defined as people who enjoyed karaoke at the same bar during the same period as the cases and tested negative. Odds ratio (OR) and confidence interval (CI) were calculated. ORs were adjusted by variables with significantly high odds ratio (aOR). Results We identified 81 cases, the majority of whom were active elderly individuals (median age: 75 years). Six cases died (case fatality ratio: 7%). Among the cases, 68 (84%) were guests, 18 of whom had visited more than two karaoke bars. A genome analysis conducted in 30 cases showed six types of isolates within four single-nucleotide variations difference. The case-control study revealed that singing (aOR 11.0, 95% CI, 1.2-101.0), not wearing a mask (aOR 3.7, 95% CI 1.2-11.2) and time spent per visit (aOR 1.7, 95% CI 1.1-2.7) were associated with COVID-19 infection. Conclusions A karaoke-related COVID-19 outbreak that occurred in two different cities was confirmed by the results of genome analysis. Singing in less-ventilated, indoor and crowded environments increases the risk of acquiring SARS-CoV-2 infection. Wearing a mask and staying for only a short time can reduce the risk of infection during karaoke.

Transmission Risk of Severe Acute Respiratory Syndrome Coronavirus 2 before and after Symptom Onset of the Infector.

An outbreak of coronavirus 2019 (COVID-19) occurred in Ueda City, Nagano prefecture, Japan, which has a population of 150,000. The residents were a population naïve to COVID-19, and many of them had only one chance of exposure, in which careful epidemiological investigation could reveal attack rates among close contact on the specific date of exposure. We identified 89 cases and 328 close contacts. Among the close contacts, 114 had only one chance of exposure to the 20 index cases. During the follow-up period, 17 close contacts tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), overall attack rate of 15%, after the exposure to 6 infectors. The median number of close contacts for the 6 infectors was 5.5 (range 2-14). Attack rates among these close contacts were 13% (1/8), 20% (2/5), 33% (2/6), 50% (1/2), 64% (4/9 and 5/5), and 100% (2/2), respectively. The transmission risk of SARS-CoV-2 appears to peak one day before symptom onset, and is at similar levels two days before (16%) and on the day (20%) of symptom onset. A multidisciplinary approach is needed to control the COVID-19 outbreak, in addition to investigation, which began after case identification.

Enhanced event-based surveillance for imported diseases during the Tokyo 2020 Olympic and Paralympic Games.

In 2021, the National Institute of Infectious Diseases, Japan, undertook enhanced event-based surveillance (EBS) for infectious diseases occurring overseas that have potential for importation (excluding coronavirus disease 2019 [COVID-19]) for the Tokyo 2020 Olympic and Paralympic Summer Games (the Games). The pre-existing EBS system was enhanced using the World Health Organization Epidemic Intelligence from Open Sources system and the BlueDot Epidemic Intelligence platform. The enhanced EBS before and during the Games did not detect any major public health event that would warrant action for the Games. However, information from multiple sources helped us identify events, characterize risk and improve confidence in risk assessment. The collaboration also reduced the surveillance workload of the host country, while ensuring the quality of surveillance, even during the COVID-19 pandemic.

Reduced mortality during the COVID-19 outbreak in Japan, 2020: a two-stage interrupted time-series design.

BACKGROUND: Coronavirus disease 2019 (COVID-19) continues to be a major global health burden. This study aims to estimate the all-cause excess mortality occurring in the COVID-19 outbreak in Japan, 2020, by sex and age group. METHODS: Daily time series of mortality for the period January 2015-December 2020 in all 47 prefectures of Japan were obtained from the Ministry of Health, Labour and Welfare, Japan. A two-stage interrupted time-series design was used to calculate excess mortality. In the first stage, we estimated excess mortality by prefecture using quasi-Poisson regression models in combination with distributed lag non-linear models, adjusting for seasonal and long-term variations, weather conditions and influenza activity. In the second stage, we used a random-effects multivariate meta-analysis to synthesize prefecture-specific estimates at the nationwide level. RESULTS: In 2020, we estimated an all-cause excess mortality of -20 982 deaths [95% empirical confidence intervals (eCI): -38 367 to -5472] in Japan, which corresponded to a percentage excess of -1.7% (95% eCI: -3.1 to -0.5) relative to the expected value. Reduced deaths were observed for both sexes and in all age groups except those aged <60 and 70-79 years. CONCLUSIONS: All-cause mortality during the COVID-19 outbreak in Japan in 2020 was decreased compared with a historical baseline. Further evaluation of cause-specific excess mortality is warranted.

Proactive Engagement of the Expert Meeting in Managing the Early Phase of the COVID-19 Epidemic, Japan, February-June 2020.

To deal with the risk of emerging diseases with many unknowns, close and timely collaboration and communication between science experts and policymakers are crucial to developing and implementing an effective science-based intervention strategy. The Expert Meeting, an ad hoc medical advisory body, was established in February 2020 to advise Japan's COVID-19 Response Headquarters. The group played an important role in the policymaking process, promoting timely situation awareness and developing science-based proposals on interventions that were promptly reflected in government actions. However, this expert group may have been overly proactive in taking on the government's role in crisis management. For the next stage of managing the coronavirus disease pandemic and future pandemics, the respective roles of the government and its advisory bodies need to be clearly defined. Leadership and strategic risk communication by the government are key.

Epidemiology of Coronavirus Disease 2019 in Japan: Descriptive Findings and Lessons Learned through Surveillance during the First Three Waves.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) has caused unprecedented global morbidity and mortality. Japan has faced three epidemic "waves" of COVID-19 from early 2020 through early 2021. Here we narratively review the three waves in Japan, describe the key epidemiologic features of COVID-19, and discuss lessons learned. METHODS: We assessed publicly available surveillance data, routine surveillance reports, and other relevant sources-multiple indicators were monitored to improve interpretation of surveillance data. Weekly trends for each wave were described based on the number of case notifications; number of tests performed; proportion of those tests that were positive for the novel coronavirus; the prevalent number of COVID-19 hospitalizations (total hospitalizations and those categorized as severe); and number of COVID-19 deaths. For each indicator and wave, we recorded the first calendar week to show an increase over two consecutive previous weeks, along with the peak week. RESULTS: The spring wave was characterized by detection of cases imported from China, followed by notifications of sporadic cases without travel history, clusters, and mild/asymptomatic cases. The summer wave saw a large increase in notifications and a younger age distribution, but in the context of increased testing with lower test positivity. The winter wave brought considerable morbidity and mortality, surpassing the cumulative case counts and fatalities from the earlier waves, with high peak values. Overall, relative to the first wave, the burden of severe outcomes was lower in the second and higher in the third wave, but varied by prefecture. In all three waves, severe outcomes peaked after notification counts and test positivity peaked; severe outcomes were also consistently skewed toward the elderly. CONCLUSIONS: Important lessons were learned from each wave and across waves-some aspects remained constant, while others changed over time. In order to rapidly detect an increase in incidence, continuous, timely, and sensitive surveillance-using multiple information sources with careful interpretations-will be key in COVID-19 control.

Clinical Characteristics and Risk Factors for Severe Outcomes of Novel Coronavirus Infection, January-March 2020, Japan.

BACKGROUND: Notifications of novel coronavirus infections increased in early 2020 in Japan. We described characteristics of novel coronavirus infection cases and analyzed risk factors for severe outcomes. METHODS: Cases were persons with laboratory-confirmed novel coronavirus infection reported under national surveillance between January and March 2020. Clinical characteristics were described, and risk factors of (1) intensive care unit [ICU] admission and (2) invasive ventilation/death were analyzed using Poisson regression. RESULTS: Among the 516 cases analyzed, median age was 60 years (range: 1-97 years) and 285 (55%) were male. Common symptoms/signs were fever (375/475, 79%), cough (353/465, 76%), and pneumonia (245/387, 63%). Ten (2%) cases died. Of the 348 cases with data, 50 (14%) required invasive ventilation. Adjusted for each other, male gender and 1-year increase in age were associated with ICU admission (risk ratio [RR] 4.18; 95% confidence interval [CI], 1.69-10.32 and RR 1.05; 95% CI, 1.03-1.08, respectively) and invasive ventilation/death (RR 2.79; 95% CI, 1.49-5.21 and RR 1.06; 95% CI, 1.04-1.08, respectively). Diabetes, dyslipidemia, hyperuricemia, and lung diseases were also associated with severe outcomes. Of the 80 cases asymptomatic at hospitalization, 40 developed symptoms and five of them >70 years of age required invasive ventilation. CONCLUSIONS: The early stage of the novel coronavirus epidemic in Japan disproportionately affected the elderly. Older age, male gender, and underlying conditions were associated with severe outcomes. Notably, some elderly case-patients who were asymptomatic at diagnosis and promptly hospitalized still went on to develop severe disease, indicating the importance of careful monitoring of certain populations.

Excess All-Cause Deaths during Coronavirus Disease Pandemic, Japan, January-May 20201.

To provide insight into the mortality burden of coronavirus disease (COVID-19) in Japan, we estimated the excess all-cause deaths for each week during the pandemic, January-May 2020, by prefecture and age group. We applied quasi-Poisson regression models to vital statistics data. Excess deaths were expressed as the range of differences between the observed and expected number of all-cause deaths and the 95% upper bound of the 1-sided prediction interval. A total of 208-4,322 all-cause excess deaths at the national level indicated a 0.03%-0.72% excess in the observed number of deaths. Prefecture and age structure consistency between the reported COVID-19 deaths and our estimates was weak, suggesting the need to use cause-specific analyses to distinguish between direct and indirect consequences of COVID-19.

A Genome Epidemiological Study of SARS-CoV-2 Introduction into Japan.

After the first case of coronavirus disease 2019 (COVID-19) in Japan on 15 January 2020, multiple nationwide COVID-19 clusters were identified by the end of February. The Japanese government focused on mitigating the emerging COVID-19 clusters by conducting active nationwide epidemiological surveillance. However, an increasing number of cases continued to appear until early April 2020, many with unclear infection routes and no recent history of travel outside Japan. We aimed to evaluate the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genome sequences from the COVID-19 cases that appeared until early April 2020 and to characterize their genealogical networks in order to demonstrate possible routes of spread in Japan. Nasopharyngeal specimens were collected from patients, and reverse transcription-quantitative PCR tests for SARS-CoV-2 were performed. Positive RNA samples were subjected to whole-genome sequencing, and a haplotype network analysis was performed. Some of the primary clusters identified during January and February 2020 in Japan descended directly from the Wuhan-Hu-1-related isolates from China and other distinct clusters. Clusters were almost contained until mid-March; the haplotype network analysis demonstrated that the COVID-19 cases from late March through early April may have created an additional large cluster related to the outbreak in Europe, leading to additional spread within Japan. In conclusion, genome surveillance has suggested that there were at least two distinct SARS-CoV-2 introductions into Japan from China and other countries.IMPORTANCE This study aimed to evaluate the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genome sequences from COVID-19 cases and to characterize their genealogical networks to demonstrate possible routes of spread in Japan. We found that there were at least two distinct SARS-CoV-2 introductions into Japan, initially from China and subsequently from other countries, including Europe. Our findings can help understand how SARS-CoV-2 entered Japan and contribute to increased knowledge of SARS-CoV-2 in Asia and its association with implemented stay-at-home/shelter-in-place/self-restraint/lockdown measures. This study suggested that it is necessary to formulate a more efficient containment strategy using real-time genome surveillance to support epidemiological field investigations in order to highlight potential infection linkages and mitigate the next wave of COVID-19 in Japan.

Clusters of Coronavirus Disease in Communities, Japan, January-April 2020.

We analyzed 3,184 cases of coronavirus disease in Japan and identified 61 case-clusters in healthcare and other care facilities, restaurants and bars, workplaces, and music events. We also identified 22 probable primary case-patients for the clusters; most were 20-39 years of age and presymptomatic or asymptomatic at virus transmission.

Severe Acute Respiratory Syndrome Coronavirus 2 Infection among Returnees to Japan from Wuhan, China, 2020.

In early 2020, Japan repatriated 566 nationals from China. Universal laboratory testing and 14-day monitoring of returnees detected 12 cases of severe acute respiratory syndrome coronavirus 2 infection; initial screening results were negative for 5. Common outcomes were remaining asymptomatic (n = 4) and pneumonia (n = 6). Overall, screening performed poorly.