ABSTRACT
We propose an inference method for detecting multiple change points in high-dimensional time series, targeting dense or spatially clustered signals. Our method aggregates moving sum (MOSUM) statistics cross-sectionally by an $\ell^2$-norm and maximizes them over time. We further introduce a novel Two-Way MOSUM, which utilizes spatial-temporal moving regions to search for breaks, with the added advantage of enhancing testing power when breaks occur in only a few groups. The limiting distribution of an $\ell^2$-aggregated statistic is established for testing break existence by extending a high-dimensional Gaussian approximation theorem to spatial-temporal non-stationary processes. Simulation studies exhibit promising performance of our test in detecting non-sparse weak signals. Two applications, analyzing equity returns and COVID-19 cases in the United States, showcase the real-world relevance of our proposed algorithms.
Subject(s)
COVID-19ABSTRACT
Background: Hainan Island, which is a popular tourist destination, received many imported cases of Coronavirus disease 2019 (COVID-19) but successfully contained the epidemic within one month. We described the epidemiological and clinical characteristics of COVID-19 in Hainan and compared these features between imported and local cases to provide information for other international epidemic areas. Methods: : We included 91 patients (56 imported and 35 local cases) from two designated hospitals for COVID-19 in Haikou, China, from January 20 to February 19, 2020. Data on the demographic, epidemiological, clinical and laboratory characteristics were extracted from medical records. Patients were followed until April 21, 2020, and the levels of antibodies at the follow-ups were also analyzed. Results: : Of the 91 patients, 78 (85.7%) patients were diagnosed within the first three weeks after the first case was identified (Day 1: Jan 22, 2020), while the number of local cases started to increase during the third week. No new cases occurred after Day 29. Fever and cough were two main clinical manifestations. In total, 15 (16.5%) patients were severe, 14 (15.4%) had complicated infections, nine (9.9%) were admitted to the ICU, and three died. The median duration of viral shedding in feces was longer than that in nasopharyngeal swabs (19 days vs 16 days, P =0.007). Compared with local cases, imported cases were older and had a higher incidence of fever and concurrent infections. There was no difference in outcomes between the two groups. IgG was positive in 92.8% patients (77/83) in the follow-up at week 2 after discharge, while 88.4% patients (38/43) had a reduction in IgG levels in the follow-up at week 4 after discharge, and the median level was lower than that in the follow-up at week 2 (10.95 S/CO vs 15.02 S/CO, P<0.001). Conclusion: Imported cases were more severe than local cases but had similar prognoses. The level of IgG antibodies declined from week 6 to week 8 after onset. The short epidemic period in Hainan suggests that the epidemic could be quickly brought under control if proper timely measures were taken.
Subject(s)
COVID-19 , Encephalitis, Arbovirus , FeverABSTRACT
Background: Confirmed cases of coronavirus disease 2019 (COVID-19) is still increasing, detailed analysis of confirmed cases may be beneficial for disease control.Methods: To describe the clinical and radiological findings of patients confirmed with COVID-19 infection in Haikou, China.Results: A total of 67 patients confirmed with COVID-19 infection were included in this study. 50 were imported cases. Most infected patients presented with fever and cough. The typical CT findings of lung lesions were bilateral, multifocal lung lesions (52[78%]), with subpleural distribution, and more than two lobes involved (51[78%]). 54 (81%) patients of COVID-19 pneumonia had ground glass opacities. Consolidation was in 30 (45%) patients, crazy paving pattern or interlobular thickening in 17 (25%), adjacent pleura thickening in 23 (34%) patients. Additionally, baseline chest CT did not reveal positive CT findings in 7 patients (23%), but 3 patients presented unilateral ground glass opacities at follow-up. Importantly, the follow-up CT findings were fitted well with the clinical outcomes.Conclusions: Chest CT could be used as an important tool for early diagnosis of COVID-19, monitoring the disease evolution, judging the treatment effectiveness and predicting the clinical outcomes.
Subject(s)
Lung Diseases , Infections , Fever , Pneumonia , Cough , COVID-19ABSTRACT
Background Hainan Island, a popular tourist destination, had received many imported cases of Coronavirus disease 2019 (COVID-19), but successfully contained the epidemics in one month. We described epidemiological and clinical characteristics of COVID-19 in Hainan and compared these features between imported and local cases to provide information for other international epidemic areas. Methods We included 91 patients (56 imported and 35 local cases) from two designed hospitals for COVID-19 in Haikou, China, from January 20 to February 19, 2020. Data on demographic, epidemiological, clinical and laboratory characteristics were extracted from medical records. Results Of the 91 patients, 78 (85.7%) patients were diagnosed within the first three weeks after the first case identified (Day 1: Jan 22, 2020), while the number of local cases started to increase from the third week. No new cases occurred after Day 29. Fever and cough were two main clinical manifestations. 15 (16.5%) were severe, 14 (15.4%) had complicated infections, nine (9.9%) were admitted to ICU, and three died. Median duration of viral shedding in feces was longer than that in nasopharyngeal swabs (19 days vs 16 days, P =0.007). Compared with local cases, imported cases were older, have higher incidence of fever and concurrent infections. There was no difference in outcomes between the two groups. Conclusion Imported cases were more severe than local cases, but could have similar prognosis. The short epidemic period in Hainan suggests that the epidemics could be quickly brought under control if proper timely measures were taken.
Subject(s)
COVID-19ABSTRACT
Background The outbreak of sever acute respiratory syndrome coronavirus 2(SARS-CoV-2) has become a great threat to the world. No study has been done on the mild or asymptomatic SARS-CoV-2 in a family cluster.Methods We report the epidemiological, clinical, laboratory, radiological, and clinical outcomes of five patients in a family cluster.Results We enrolled a family of five patients who was confirmed with SARS-CoV-2 infection. One of them worked in Wuhan and returned to Danzhou, Hainan on January 22,2020. The other four family members, who did not travel to Wuhan, became infected with the virus after several days of contact with the family member. Five family members (aged 33–57 years) presented with fever, cough or no symptom onset. Three of them had negative nucleic test on first swab sampling. One of them was not confirmed until the third nucleic acid test. Two of them had radiological ground-glass lung opacities. Two patients presenting with fever had lymphopenia or decreased white blood cells. No one had increased C-reactive protein or lactate dehydrogenase levels. After treatment, they were discharged.Conclusions Person-to-person transmission of SARS-CoV-2 was confirmed in family setting. Concerns should be raised for the asymptomatic persons in a family cluster.
Subject(s)
Fever , Severe Acute Respiratory Syndrome , Cough , COVID-19 , LymphopeniaABSTRACT
Background: The outbreak of sever acute respiratory syndrome coronavirus 2(SARS-CoV-2) has become a great threat to the world. No study has been done on the mild or asymptomatic SARS-CoV-2 in a family cluster.Methods: We report the epidemiological, clinical, laboratory, radiological, and clinical outcomes of five patients in a family cluster.Results: We enrolled a family of five patients who was confirmed with SARS-CoV-2 infection. One of them worked in Wuhan and returned to Danzhou, Hainan on January 22,2020. The other four family members, who did not travel to Wuhan, became infected with the virus after several days of contact with the family member. Five family members (aged 33–57years) presented with fever, cough or no symptom onset. Three of them had negative nucleic test on first swab sampling. One of them was not confirmed until the third nucleic acid test. Two of them had radiological ground-glass lung opacities. Two patients presenting with fever had lymphopenia or decreased white blood cells. No one had increased C-reactive protein or lactate dehydrogenase levels. After treatment, they were discharged.Conclusions: Person-to-person transmission of SARS-CoV-2 was confirmed in family setting. Concerns should be raised for the asymptomatic persons in a family cluster.
Subject(s)
Fever , Severe Acute Respiratory Syndrome , Cough , COVID-19 , LymphopeniaABSTRACT
To describe the clinical and radiological findings of patients confirmed with 2019 novel coronavirus disease (COVID-19) infection in Haikou, China. A total of 67 patients confirmed with COVID-19 infection were included in this study. 50 were imported cases. Most infected patients presented with fever and cough. The typical CT findings of lung lesions were bilateral, multifocal lung lesions (52[78%]), with subpleural distribution, and more than two lobes involved (51[78%]). 54 (81%) patients of COVID-19 pneumonia had ground glass opacities. Consolidation was in 30 (45%) patients, crazy paving pattern or interlobular thickening in 17 (25%), adjacent pleura thickening in 23 (34%) patients. Additionally, baseline chest CT did not reveal positive CT findings in 7 patients (23%), but 3 patients presented unilateral ground glass opacities at follow-up. Importantly, the follow-up CT findings were fitted well with the clinical outcomes.
Subject(s)
Lung Diseases , Infections , Fever , Pneumonia , Cough , COVID-19ABSTRACT
Objective: To elucidate the consistency between CT findings and real time reverse-transcription–polymerase chain- reaction (RT-PCR) results and investigate the relationship between CT features and clinical prognosis in COVID-19.Methods: The clinical manifestations, laboratory parameters and CT imaging findings were analyzed in thirty-four patients with COVID-19 confirmed by RT-PCR from January 20 to February 4 in Hainan province. CT score was compared between the discharged patients and ICU patients.Results: Fever (85%) and cough (79%) were most commonly seen. 10 (29%) patients demonstrated negative results on their first RT-PCR.22/34(65%) patients showed pure ground glass opacity (GGO). 17/34 (50%) patients had five lobes of lung involvement, while the 23(68%) patients had lower lobes were involved and 24/34 (71%) were subpleural. Lesions of 24 (71%) patients were distributed mainly in the subpleural. During follow-up, the initial CT lesions of ICU patients are distributed in both subpleural and parenchyma (80%) and the lesions are scattered. 60% of ICU patients had five lobes involved, while this was seen in only 25% discharged patients. Lesions of discharged patients are mainly in the subpleural (75%). 62.5% of discharged patients showed pure ground-glass opacity. 80% ICU demonstrated progressive stage on their first CT scan. 75 % discharged patients were at an early stage. CT score of ICU patients were significantly higher than that of the discharged patients.Conclusion: Chest CT plays a crucial role in the early diagnosis of COVID-19, particularly for those patients with negative RT-PCR. The initial features in CT may be associated with prognosis.Authors Hui Juan Chen and Jie Qiu contributed equally to this work.