Efficacy and Safety of an mRNA-Based RSV PreF Vaccine in Older Adults.

BACKGROUND: Respiratory syncytial virus (RSV) can cause substantial morbidity and mortality among older adults. An mRNA-based RSV vaccine, mRNA-1345, encoding the stabilized RSV prefusion F glycoprotein, is under clinical investigation. METHODS: In this ongoing, randomized, double-blind, placebo-controlled, phase 2-3 trial, we randomly assigned, in a 1:1 ratio, adults 60 years of age or older to receive one dose of mRNA-1345 (50 µg) or placebo. The two primary efficacy end points were the prevention of RSV-associated lower respiratory tract disease with at least two signs or symptoms and with at least three signs or symptoms. A key secondary efficacy end point was the prevention of RSV-associated acute respiratory disease. Safety was also assessed. RESULTS: Overall, 35,541 participants were assigned to receive the mRNA-1345 vaccine (17,793 participants) or placebo (17,748). The median follow-up was 112 days (range, 1 to 379). The primary analyses were conducted when at least 50% of the anticipated cases of RSV-associated lower respiratory tract disease had occurred. Vaccine efficacy was 83.7% (95.88% confidence interval [CI], 66.0 to 92.2) against RSV-associated lower respiratory tract disease with at least two signs or symptoms and 82.4% (96.36% CI, 34.8 to 95.3) against the disease with at least three signs or symptoms. Vaccine efficacy was 68.4% (95% CI, 50.9 to 79.7) against RSV-associated acute respiratory disease. Protection was observed against both RSV subtypes (A and B) and was generally consistent across subgroups defined according to age and coexisting conditions. Participants in the mRNA-1345 group had a higher incidence than those in the placebo group of solicited local adverse reactions (58.7% vs. 16.2%) and of systemic adverse reactions (47.7% vs. 32.9%); most reactions were mild to moderate in severity and were transient. Serious adverse events occurred in 2.8% of the participants in each trial group. CONCLUSIONS: A single dose of the mRNA-1345 vaccine resulted in no evident safety concerns and led to a lower incidence of RSV-associated lower respiratory tract disease and of RSV-associated acute respiratory disease than placebo among adults 60 years of age or older. (Funded by Moderna; ConquerRSV ClinicalTrials.gov number, NCT05127434.).

Humoral Immunogenicity of mRNA-1345 RSV Vaccine in Older Adults.

BACKGROUND: The mRNA-1345 vaccine demonstrated efficacy against RSV disease with acceptable safety in adults ≥60 years in the ConquerRSV trial. Here, humoral immunogenicity results from the trial are presented. METHODS: This phase 2/3 trial randomly assigned adults (≥60 years) to mRNA-1345 50-µg encoding prefusion F (preF) glycoprotein (n = 17,793) vaccine or placebo (n = 17,748). RSV-A and RSV-B neutralizing antibody (nAb) and preF binding antibody (bAb) levels at baseline and day 29 post-vaccination were assessed in a per-protocol immunogenicity subset ([PPIS]; mRNA-1345, n = 1515; placebo, n = 333). RESULTS: Day 29 nAb geometric mean titers (GMTs) increased 8.4-fold against RSV-A and 5.1-fold against RSV-B from baseline. Seroresponses (4-fold rise from baseline) in the mRNA-1345 groups were 74.2% and 56.5% for RSV-A and RSV-B, respectively. Baseline GMTs were lower among participants who met the seroresponse criteria than those who did not. mRNA-1345 induced preF bAbs at day 29, with a pattern similar to nAbs. Day 29 antibody responses across demographic and risk subgroups were generally consistent with the overall PPIS. CONCLUSION: mRNA-1345 enhanced RSV-A and RSV-B nAbs and preF bAbs in adults (≥60 years) across various subgroups, including those at risk for severe disease, consistent with its demonstrated efficacy in the prevention of RSV disease.

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.

Two Cases of Breakthrough Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infections Caused by the Omicron Variant (B.1.1.529 Lineage) in International Travelers to Japan.

In November 2021, the World Health Organization designated a new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant of concern, Omicron (PANGO lineage B.1.1.529). We report on the first 2 cases of breakthrough coronavirus disease 2019 (COVID-19) caused by Omicron in Japan among international travelers returning from the country with undetected infection. The spread of infection by Omicron were considered.

Duration of Infectious Virus Shedding by SARS-CoV-2 Omicron Variant-Infected Vaccinees.

To determine virus shedding duration, we examined clinical samples collected from the upper respiratory tracts of persons infected with severe acute respiratory syndrome coronavirus 2 Omicron variant in Japan during November 29-December 18, 2021. Vaccinees with mild or asymptomatic infection shed infectious virus 6-9 days after onset or diagnosis, even after symptom resolution.

Neutralising activity and antibody titre in 10 patients with breakthrough infections of the SARS-CoV-2 Omicron variant in Japan.

The Omicron variant of severe acute respiratory syndrome coronavirus 2 has multiple amino acid mutations in its spike proteins, which may allow it to evade immunity elicited by vaccination. We examined the neutralising activity and S1-IgG titres in patients with breakthrough infections caused by the Omicron variant after two doses of vaccination. We found that neutralising activity was significantly lower for the Omicron variant than for the Wuhan strain. Two doses of vaccination might not induce sufficient neutralising activity for the Omicron variant.

Fatty liver on computed tomography scan on admission is a risk factor for severe coronavirus disease.

OBJECTIVES: To alleviate the overflow of coronavirus disease 2019 (COVID-19) patients in hospitals, less invasive and simple criteria are required to triage the patients. We evaluated the relationship between COVID-19 severity and fatty liver on plain computed tomography (CT) scan performed on admission. METHODS: In this retrospective cohort study, we considered all COVID-19 patients at a large tertiary care hospital between January 31 and August 31, 2020. COVID-19 severity was categorized into severe (moderate and severe) and non-severe (asymptomatic and mild) groups, based on the Japanese National COVID-19 guidelines. Fatty liver was detected on plain CT scan. Multivariate logistic regression analysis was performed to evaluate factors associated with severe COVID-19. RESULTS: Of 222 patients (median age: 52 years), 3.2%, 58.1%, 20.7%, and 18.0% presented with asymptomatic, mild, moderate, and severe COVID-19, respectively. Although 59.9% had no fatty liver on plain CT, mild, moderate, and severe fatty liver occurred in 13.1%, 18.9%, and 8.1%, respectively. Age and presence of fatty liver were significantly associated with severe COVID-19. CONCLUSION: Our study showed that fatty liver on plain CT scan on admission can become a risk factor for severe COVID-19. This finding may help clinicians to easily triage COVID-19 patients.

Resurgence of Respiratory Syncytial Virus Infections during COVID-19 Pandemic, Tokyo, Japan.

More than a year into the coronavirus-19 pandemic, intensified infection control measures have controlled most viral respiratory infections in Tokyo, Japan. As of July 2021, however, an unusually high number of respiratory syncytial virus infections were reported in Tokyo. This resurgence may have resulted from restarting social activities for children.

Novel SARS-CoV-2 Variant in Travelers from Brazil to Japan.

Multiple severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with higher transmission potential have been emerging globally, including SARS-CoV-2 variants from the United Kingdom and South Africa. We report 4 travelers from Brazil to Japan in January 2021 infected with a novel SARS-CoV-2 variant with an additional set of mutations.

Pulmonary histoplasmosis diagnosed in a Japanese woman after traveling to central and South America: A case report.

Histoplasmosis is a fungal infection caused by Histoplasma capsulatum, and Japan is considered a non-endemic area for histoplasmosis. Most patients diagnosed with histoplasmosis in the past usually have exposure to caves and bat guano with travel history to endemic areas. Therefore, travel history and risk activities should be comprehensively assessed when suspecting histoplasmosis because this important information may be overlooked. Although few, possibilities of indigenous cases have also been suggested. Moreover, it is assumed that the number of travelers and endemic mycoses has decreased with the recent coronavirus disease 2019 epidemic. However, clinicians should carefully consider the differential diagnosis of histoplasmosis for travelers traveling to endemic areas. In this case report, we describe an immunocompetent Japanese woman who developed histoplasmosis due to a history of travel to an endemic country. Our case report suggests that clinicians should not exclude histoplasmosis from the differential diagnosis even in the absence of risk features such as activities or immunodeficiencies during travel.

Asymptomatic COVID-19 re-infection in a Japanese male by elevated half-maximal inhibitory concentration (IC50) of neutralizing antibodies.

INTRODUCTION: "Re-infection" with COVID-19 is a growing concern; re-infection cases have reported worldwide. However, the clinical characteristics of SARS-CoV-2 re-infection, including the levels and role of anti-SARS-CoV-2 Spike protein IgG antibodies and the half-maximal concentration (IC50) of neutralizing antibodies remain unknown. METHODS: Both the epidemiological and clinical information has been collected during two episodes of COVID-19 in a patient. Laboratory results, including RT-PCR, Ct values, anti-SARS-CoV-2 Spike protein IgG antibodies, and the IC50 of neutralizing antibodies levels were analyzed on the patient. RESULTS: The patient was a 58-year-old man who developed moderate COVID-19 pneumonia with oxygen demand (cannula 2 L/min) in the first episode. By day 30, he recuperated and was discharged after testing negative for SARS-CoV-2. After two and a half months, his three family members showed COVID-19 symptoms and tested positive for SARS-CoV-2. He tested positive for SARS-CoV-2 once again and was asymptomatic (the second episode). The IC50 of neutralizing antibodies against SARS-CoV-2 greatly increased from 50.0 µg/mL (after the first episode) to 14.8 µg/mL (after the second episode), and remained strongly reactive (20.1 µl/mL) after 47 days of the second episode. CONCLUSIONS: Epidemiological, clinical, and serological analyses confirmed that the patient had re-infection instead of persistent viral shedding from first infection. Our results suggest that SARS-CoV-2 re-infection may manifest as asymptomatic with increased neutralizing antibody levels. Further studies such as the virus characteristics, immunology, and epidemiology on SARS-CoV-2 re-infection are needed.

Travel-associated chikungunya acquired in Myanmar in 2019.

Eighteen cases of chikungunya virus infection in travellers returning from Myanmar were reported to the GeoSentinel Surveillance Network, its subnetwork EuroTravNet and TropNet in 2019, reflecting an ongoing local outbreak. This report reinforces the importance of travellers as sentinels of emerging arboviral outbreaks and highlights the importance of vigilance for imported cases, due to the potential for dissemination of the virus into areas with competent local vectors and conducive environmental conditions.

Rabies post-exposure prophylactic vaccination for returning travelers to Japan.

BACKGROUND: Rabies post-exposure prophylaxis (PEP) in Japan is administered using 6 subcutaneous doses (on days 0, 3, 7, 14, 30, and 90), which is not in line with international recommendations of 4 or 5 intramuscular doses. For reducing dose frequency, we evaluate the immunogenicity of PEP with a regimen of 6 subcutaneous doses. METHOD: This prospective single-center cross-sectional study was performed between September 2013 and December 2014. We included patients underwent rabies PEP by purified chick embryo-cultured rabies vaccine Kaketsuken (PCEC-K) at our clinic, and excluded patients with a history of pre-exposure prophylaxis or PEP using rabies immunoglobulin. The rabies virus-neutralizing antibody tests were performed at the first visit to our office (doses 1-4) and at the fifth and sixth doses. RESULTS: Data were available for 43 of 59 enrolled patients. Thirty-two patients did not start PEP within 48 h after exposure to animals. The seroprotection rates (≥0.5 IU/mL) were 90.7% and 75.7%, at days 30 and 90, respectively. Despite receiving a fifth dose, 85.3% of the patients exhibited decreasing antibody titers during days 30-90 (p < 0.001). CONCLUSIONS: The seroprotection rates of PCEC-K induced subcutaneously were insufficient to prevent rabies at day 30 and 90.

[A Case of Blackwater Fever after Treatment for Plasmodium falciparum Malaria].

Blackwater fever (BWF), which causes massive intravascular hemolysis and the passage of black-colored urine, is a poorly understood condition that is rarely seen during the course of malaria. Here, we present a case of BWF that developed after treatment for falciparum malaria complicated by hyperparasitemia in a Japanese traveler. A 29-year-old woman returning from Ghana visited our travel clinic with complaints of sudden fever and headache on the third day of illness. She had taken anti-malarial drugs for intermittent malaria prophylaxis and the treatment of malaria while in Ghana. Falciparum malaria was diagnosed based on the results of a blood smear and was confirmed using PCR. She was successfully treated with a single artesunate suppository and one dose of intravenous quinine followed by artemether-lumefantrin for 3 days. She was discharged without complications on the 11th day of illness. However, she was re-admitted for fever and headache on the 16th day of illness. The recrudescence of malaria was excluded by peripheral blood smear results. BWF was diagnosed based on the presence of fever, black-colored urine, and laboratory findings suggesting intravascular hemolysis. She was treated with supportive care, including the transfusion of 10 packs of red blood cells and the maintenance of fluid and electrolyte balance, and she gradually improved within two weeks. BWF is a rare but severe complication induced by severe falciparum malaria and/or the use of the aryl-amino alcohol group of antimalarial drugs. Thus, consideration of BWF is particularly important for a rapid and accurate diagnosis.

The first case of adult-onset PFAPA syndrome in Japan.

A 26-year-old woman presented with fever and pharyngitis. She previously experienced four periodic febrile episodes at 30- to 40-day intervals. We suspected periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) syndrome, and prescribed predisolone, thereby her fever rapidly subsided. Her febrile episodes improved after daily cimetidine treatment. Genetic testing results of genomic DNA for periodic fever syndromes were negative, although she was heterozygous for p.Glu148Gln variation in MEFV, supporting the diagnosis of PFAPA syndrome.

Response to Ebola virus disease outbreak in West Africa by the Ministry of Health, Labour and Welfare of Japan in 2014-2015.

Ebola Virus Disease (EVD) is categorized in the Category 1 Infectious Disease under the Act on Infectious Disease Control. Since the Act came into effect in 1999, no confirmed case of viral hemorrhagic fevers (VHF) has been reported, though some clinical samples have been tested for VHF in the National Institute of Infectious Diseases of Japan. Ministry of Health, Labour and Welfare has monitored the situation of the EVD outbreak in West Africa since the first report from Guinea in March 2014 and reinforced quarantine and public health preparedness in August. The whole-of-government response was activated at the end of October, establishing the Ministerial meeting on the Response to the EVD presided by the Prime Minister. The responses have raised the level of preparedness for such a rare import disease like VHF; however elicited many lessons. Even if the current VHF outbreak is over, the risk of the global infectious diseases outbreak will be unchanged. The maintenance and improvement of preparedness and response for infectious diseases emergency such as the Category 1 Infectious Disease outbreak by the improvement of manuals and continuous exercises are crucial for a future domestic response. In addition, human resource development is essential for contributing to global response efforts.