Background： Elderly subjects aged 75 or over with influenza are considered at high risk of developing severe influenza and influenza-related complications. Therefore, early therapeutic intervention with antiinfluenza medications is more important in elderly patients.
Objective： To evaluate the efficacy and safety of baloxavir marboxil as compared to placebo or oseltamivir in patients who are 75 years of age or older.
Methods： Data extracted from the randomized population of a global phase III study conducted in patients at high risk of influenza-related complications (CAPSTONE-2, N=2,184) were analyzed in a subgroup of patients who were 75 years of age or older (N=156). The primary endpoint was the time to improvement of influenza symptoms (TTIIS). The clinical secondary endpoints included the time to resolution of fever ,and the virological secondary endpoints included the change in infectious virus titer. In addition, adverse events were also assessed as the safety endpoint.
Results： The median TTIIS was significantly shorter in the baloxavir marboxil (baloxavir) group than in the placebo group (65.1 hours vs. 115.8 hours, p=0.0346) and numerically shorter than that in the oseltamivir group (79.7 hours, p=0.0846). In regard to changes in the virus titer after treatment, significantly greater reductions were observed at early time-points, namely, on Day 2 and Day 3, in the baloxavir group as compared to the placebo or oseltamivir group. In regard to adverse events, no clear differences were observed among three groups.
Conclusions： Baloxavir was superior to placebo in alleviating the symptoms of influenza in patients aged 75 or older. The results suggest a larger treatment benefit of baloxavir as compared to that of oseltamivir, based on the greater degree of reduction in the influenza virus titers.

Rapid antigen testing is widely employed for the diagnosis of influenza in Japan. The results, however, should be cautiously interpreted because the false-negative rate of the test is reported to be high, in the range of 40%-50%. Therefore, the investigation of factors that influence the diagnostic performance of the test is crucial. We conducted a single-center, prospective observational study in two influenza-epidemic seasons at the study site (December 2017 to February 2018 and December 2018 to March 2019). All patients clinically suspected as having influenza in whom rapid antigen testing was performed according to the clinical-care needs were included in the study. Real-time PCR was employed as the gold standard for the detection of the influenza virus. A total of 322 patients were screened (2017-2018：159；2018-2019：163), and 313 patients were finally included in this study. The results revealed that of the 313 patients, 129 (41.2%) tested positive for real-time PCR (typeA：88, 28.1%；typeB：41, 13.1%). The overall sensitivity and specificity of the antigen test were 54.3% (95% confidence interval [CI]：45.3-63.1) and 100% (95% CI：98.0-100), respectively. The sensitivity improved with the interval from the onset of the influenza-like symptoms, namely, elevated body temperature ≧37℃, chills or subjective fever, cough, sputum production, fatigue, sore throat, myalgia/arthralgia, headache, runny nose, or nasal blockage (interval to testing：＜12 h, 38.9% [95% CI：17.3-64.3]；12-24 h, 40.5% [95% CI：25.6-56.7]；24-48 h, 65.2% [95% CI：49.8-78.6]；＞48 h, 69.6% [95% CI：47.1-86.8], p=0.03). We conclude that the sensitivity of the antigen testing possibly improves with the passage of time over the course of the illness.

We report the case of an 88-year-old woman who was admitted with pneumonia. Sputum examination revealed aerobic actinomycetales, and we initiated the patient on therapy with imipenem/cilastatin (IPM/CS). However, the fever persisted, and the radiological findings started to worsen. On day 6 of the illness, N. otitidiscaviarum was identified by MALDI-TOF MS (Matrix As- sisted Laser Desorption Ionization Time of Flight Mass Spectrometry). We changed the antibacterial drug to ST, following which the patient improved. It has been reported that some bacterial species causing pulmonary nocardiosis show natural resistance to certain antibiotics. While not downplaying the significance of culture and drug sensitivity examinations, we suggest that for rare bacterial species, such as in the present case, the application of MALDI-TOF MS for identifying the bacterial species potentially allows early selection of effective therapeutic agents.

Background：Previous reports have documented ground-glass opacities (GGOs), followed by appearance of the crazy pavement pattern and consolidation as the typical findings on chest computed tomography (CT) in patients with Coronavirus Disease-2019 (COVID-19). Case : A 69-year-old man with chronic renal failure and diabetes mellitus presented with a 2-day history of fever and fatigue, without cough or sputum production. Chest auscultation revealed coarse crackles at the right base. Laboratory findings included a normal leukocyte count, normal serum procalcitonin level, and a slightly elevated serum C-reactive protein level. Chest CT performed on day 2 after symptom onset revealed consolidation in the right lower lobe with an air bronchogram. The patient was tentatively diagnosed as having bacterial pneumonia, however, antibiotic treatment with ampicillin/sulbactam yielded no improvement of the symptoms, respiratory status, or laboratory findings. A repeat chest CT revealed changes in the findings of the right lower lobe from areas of focal consolidation to GGOs. GGOs and areas of consolidation were also detected in the other lung lobes. A polymerase chain reaction test for Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-CoV-2) returned a positive result. Discussion：Focal areas of lung consolidation is an atypical radiological presentation of coronavirus pneumonia. It is possible that the initial findings of CT represented those of bacterial pneumonia which responded to the antibiotic therapy, and that the GGOs that developed subsequently reflected newonset SARS-CoV-2 pneumonia. However, the symptom of fatigue without cough or sputum, a normal leukocyte count, and a poor response to antibiotics are not typical findings of bacterial pneumonia. Our experience suggests that it is important to consider other or concomitant diseases when the initial treatment is followed by a deteriorating clinical course in patients with pneumonia. Moreover, it is essential to prevent the spread of hospital-acquired infection, especially if epidemic diseases need to be included in the initial differential diagnosis. Conclusion：Patients with focal consolidations could have COVID-19. Further research into consolidation as a feature of this disease is warranted.

Helicobacter cinaedi is a gram-negative spiral bacillus. The bacterium is known to cause opportunistic infections in immunocompromised hosts with blood cancer or HIV infection, but infected aneurysms caused by H. cinaedi are very rare. Herein, we report the case of a patient with an infected abdominal aortic aneurysm (AAA) caused by H. cinaedi. A man in his 60s complained of abdominal pain. He had the history of AAA and thoracic aortic aneurysm treated with graft replacements, respectively. Findings of abdominal computed tomography (CT) led to the suspicion of an AAA with impending rupture, and the patient was admitted to our hospital. On admission, laboratory tests revealed marked elevation of the serum levels of inflammatory biomarkers. An infected AAA was suspected and specimens were obtained for blood culture. The patient was started on treatment with doripenem (DRPM) plus daptomycin (DAP). However, the results of blood culture obtained three days later revealed gram-positive spiral bacilli, and DAP was switched to levofloxacin (LVFX). H. cinaedi was identified by Matrix Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS). On day 7 after admission, CT revealed an increase in the size of the AAA, suggesting an even higher risk of rupture. Therefore, laparotomy was performed for abdominal aortic replacement with a prosthetic graft. Since the antimicrobial susceptibility testing revealed that the H. cinaedi was resistant to LVFX, LVFX was discontinued after the operation. The postoperative course was uneventful and the patient was transferred to another hospital for further management on day 33. He had received antibiotics for six weeks. We confirmed H. cinaedi as the causative bacterium by genetic analysis of tissue samples obtained from the resected AAA, and the patient was diagnosed as having had an infected AAA caused by H. cinaedi. Although genetic analysis is the gold standard to identify H. cinaedi, MALDI-TOF MS is also useful. Thus, H. cinaedi should be considered as one of the possible causative pathogens in patients diagnosed as having infected aortic aneurysms.

The novel coronavirus disease 2019 (COVID-19) was first reported to the World Health Organization by the WHO country office in China in December 2019 and has since become a worldwide pandemic. In Japan, COVID-19 is a designated infectious disease under the Infectious Disease Control Act, meaning that hospitalization or isolation measures are required for infected persons. It has been noted that in some cases, patients show positive PCR test results even after discharge from the hospital upon meeting the discharge criteria for COVID-19. However, so far, there is a lack of substantial evidence on the pathogenesis of reinfection or relapse in patients with COVID-19. We report 4 cases of COVID-19 who showed repeat-positive PCR test results for SARS-COV-2 after discharge from the hospital, and assessed their infectivity using clinical information collected via a public epidemiological survey. All 4 cases showed a repeat-positive PCR test results within 40 days of the initial onset of symptoms. All the PCR test results showed high Ct values of 33 or higher in the repeat-positive test. In addition, neutralizing antibodies were detected in all cases within 3 days from the date of the repeat-positive test. Furthermore, an epidemiological survey was conducted in 18 persons who were in close contact with the 4 cases, and 11 of them tested negative by the PCR test, and no case of secondary infection was found. Based on these findings, the risk of secondary infection from the 4 cases was considered as low. No specimens collected at the time of the first infection or virus culture test results were available for further evaluation. Issues remain to be resolved in respect of the systems needed for cooperation with healthcare providers and the laboratory testing required for the evaluation of re-infection. In order to further elucidate the pathogenesis of COVID-19, and to provide appropriate medical care, it is essential to evaluate the infectivity of patients with a repeat-positive PCR test and to accumulate further knowledge about the disease.

The first wave of the coronavirus disease 2019 (COVID-19) epidemic occurred between March 2020 and May 2020 in Japan. The first epidemic wave in Chiba prefecture was analyzed based on the case series reported by the official health department of Chiba prefecture. The mean interval from the onset of symptoms to a definitive diagnosis by PCR was 6.9 days. The number of cases of infection, onset of symptoms, and of definitive diagnosis peaked on March 31, April 2 and April 10, respectively. The effective reproduction number was below 1.0 in February, 2.0 to 3.0 between March 17 and March 27, and decreased to under 1.0 again after April 2, 2020. Some patients with an infectious duration of more than 10 days showed an effective reproduction number in the 3.0 to 4.0 range at the peak of the first epidemic.