A 35-year-old woman presented with fever and mild diarrhoea without any respiratory symptoms 9 days after travelling to Japan from Wuhan, China. Her computed tomography scan revealed pneumonia. The first polymerase chain reaction (PCR) test on throat swab for the novel corona virus upon admission was negative. Therefore, she was treated for communityacquired pneumonia, but fever persisted. On hospital day 5, PCR test on induced sputum was positive, but a second polymerase chain reaction test on throat swab remained negative. She was discharged, fully recovered, on hospital day 12. A lower respiratory tract specimen should be obtained for better diagnosis of corona virus disease 2019, even in the absence of respiratory symptoms for patients with significant travel or exposure history. KEYWORDS Coronavirus disease 2019 (COVID-19) the novel corona virus (SARS-CoV-2) real-time reverse transcription-polymerase chain reaction (RT-PCR) assay ARTICLE HISTORY

A 42-year-old man exhibiting hypoxia was diagnosed with coronavirus disease 2019. He had medical histories of type 2 diabetes, hyperlipidemia, hyperuricemia, and gout attack. He received favipiravir for compassionate use for 14 days. Subsequently, he showed increased uric acid levels and developed acute gouty arthritis. Favipiravir may induce not only hyperuricemia but also acute gouty arthritis. It should therefore be used with caution in patients with a history of gout and those with hyperuricemia, especially when used at a higher dose and for a longer duration than is typical.

The mortality of coronavirus disease 2019 (COVID-19) is strongly correlated with pulmonary vascular pathology accompanied by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection–triggered immune dysregulation and aberrant activation of platelets. We combined histological analyses using field emission scanning electron microscopy with energy-dispersive X-ray spectroscopy analyses of the lungs from autopsy samples and single-cell RNA sequencing of peripheral blood mononuclear cells to investigate the pathogenesis of vasculitis and immunothrombosis in COVID-19. We found that SARS-CoV-2 accumulated in the pulmonary vessels, causing exudative vasculitis accompanied by the emergence of thrombospondin-1–expressing noncanonical monocytes and the formation of myosin light chain 9 (Myl9)–containing microthrombi in the lung of COVID-19 patients with fatal disease. The amount of plasma Myl9 in COVID-19 was correlated with the clinical severity, and measuring plasma Myl9 together with other markers allowed us to predict the severity of the disease more accurately. This study provides detailed insight into the pathogenesis of vasculitis and immunothrombosis, which may lead to optimal medical treatment for COVID-19.

We herein report the first case of a fever induced by favipiravir, a potential coronavirus disease 2019 therapeutic drug. An 82-year-old man diagnosed with bilateral pneumonia was transferred to our hospital following a positive severe acute respiratory syndrome coronavirus 2 polymerase chain reaction test. He was treated with compassionate use of favipiravir. Both his oxygen demand and fever gradually improved after admission; however, his fever relapsed, and the C-reactive protein (CRP) levels increased on day 7. We diagnosed his fever as being favipiravir-induced. The fever resolved a few days after favipiravir discontinuation, demonstrating the accuracy of the diagnosis. This case revealed that favipiravir can induce a fever.

Limited data are available regarding the seroprevalence of measles, mumps, rubella, and varicella (MMRV) among emergency medical technicians (EMTs) in Japan. The present study aimed to review a project to evaluate adequate immunity against MMRV for the requirement of additional vaccination among EMTs in accordance with the Japanese Society for Infection Prevention and Control guidelines. A retrospective observational study was conducted as part of a vaccination program for EMTs. Each participant was evaluated for medical history, vaccination history, and serology using the criteria established by the Japanese Society of Infection Prevention and Control. In total, 85 EMTs (median age, 31 years; male, 92.9%) were included. Among the included EMTs, 32 (37.6%), 54 (63.5%), 46 (54.1%), and 84 (98.9%) were seropositive for measles, rubella, mumps, and varicella, respectively, whereas 1 (1.2%), 6 (7.1%), 5 (5.9%), and 0 (0%) were seronegative. Furthermore, 48 (56.5%), 27 (31.8%), 45 (52.9%), and 8 (9.4%) EMTs received an additional dose of vaccines for measles, rubella, mumps, and varicella, respectively. The present study suggests that EMTs are not fully immune to MMRV, which highlights the need for confirming the immune status and additional vaccination requirement to prevent occupational infections.