Addressing practical issues in the smooth implementation of revised guidelines for non-clinical studies of vaccines for infectious disease prevention.

Herein, we investigated possible practical issues for the smooth implementation of the revised Japanese Guidelines for Non-clinical Studies of Vaccines for the Prevention of Infectious Diseases, which were raised in response to public comments on the proposed guideline revision and a gap analysis of the World Health Organization and European Medicines Agency guidelines. We identified main issues such as the non-clinical safety studies of adjuvants and evaluation of local cumulative tolerance in toxicity studies. The revised Japanese Pharmaceuticals and Medical Devices Agency (PMDA)/Ministry of Health, Labour and Welfare (MHLW) guidelines require non-clinical safety studies for vaccines containing new adjuvants, but additional safety pharmacology studies or safety studies in two animal species may be required if non-clinical safety studies raise any concerns (i.e., systemic distribution). Adjuvant biodistribution studies may aid in understanding vaccine characteristics. The evaluation of local cumulative tolerance in non-clinical studies, which was the focus of the Japanese review, can be omitted by including a warning in the package insert to avoid injection to the same site. The study's findings will be reflected in a Q&A to be released by the Japanese MHLW. We hope that this study will contribute to the global and harmonized development of vaccines.

The clinical characteristics of pediatric coronavirus disease 2019 in 2020 in Japan.

BACKGROUND: The COVID-19 pandemic has affected the lives of people of all ages. Most reports on pediatric cases suggest that children experience fewer and milder symptoms than do adults. This is the first nationwide study in Japan focusing on pediatric cases reported by pediatricians, including cases with no or mild symptoms. METHODS: We analyzed the epidemiological and clinical characteristics and transmission patterns of 840 pediatric (<16 years old) COVID-19 cases reported between February and December 2020 in Japan, using a dedicated database which was maintained voluntarily by members of the Japan Pediatric Society. RESULTS: Almost half of the patients (47.7%) were asymptomatic, while most of the others presented mild symptoms. At the time of admission or first outpatient clinic visit, 84.0% of the cases were afebrile (<37.5°C). In total, 609 cases (72.5%) were exposed to COVID-19-positive household members. We analyzed the influence of nationwide school closures that were introduced in March 2020 on COVID-19 transmission routes among children in Japan. Transmission within households occurred most frequently, with no significant difference between the periods before and after declaring nationwide school closures (70.9% and 74.5%, respectively). CONCLUSIONS: COVID-19 symptoms in children are less severe than those in adults. School closure appeared to have a limited effect on transmission. Controlling household transmission from adult family members is the most important measure for prevention of COVID-19 among children.

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.

Zika virus protease induces caspase-independent pyroptotic cell death by directly cleaving gasdermin D.

The association of Zika virus (ZIKV) infection with a congenital malformation in fetuses, neurological, and other systemic complications in adults have brought significant global health emergency. ZIKV targets nerve cells in the brain and causes cell death, such as pyroptosis, leading to neuroinflammation. Here we described a novel mechanism of pyroptosis caused by ZIKV protease. We found that ZIKV protease directly cleaved the GSDMD into N-terminal fragment (1-249) leading to pyroptosis in a caspase-independent manner, suggesting a direct mechanism of ZIKV-induced cell death and subsequent inflammation. Our findings might shed new light to explore the pathogenesis of ZIKV infections where ZIKV protease might be a suitable target for the development of antiviral agents.

Prolonged viral shedding of SARS-CoV-2 in an immunocompromised patient.

The duration of viral shedding of SARS-CoV-2 is usually less than 10 days. We experienced a COVID-19 case with prolonged viral shedding for 2 months. His cell mediated immunity has been depressed (CD4+T cell <100/µl) due to advanced malignant lymphoma and chemotherapy which had been completed 4 months prior to the onset of symptoms of COVID-19. We administered several treatments against COVID-19, however the results of Polymerase Chain Reaction (PCR) from nasopharyngeal specimens remained positive to SARS-CoV-2 for 2 months. Moreover, virus isolation assays performed on Day 59 also remained positive. He was finally discharged on Day 69 with two consecutive negative PCR results for SARS-CoV-2. Immunocompromised status may prolong viral shedding and it is therefore important for the clinician to take into account this when assessing such patients.

Passive surveillance of rotavirus gastroenteritis-associated hospitalization using nationwide administrative databases in Japan.

Simple, systematic, and sustainable passive surveillance systems for vaccine-preventable diseases (VPDs) should be useful to quantify the clinical and economic burden in a timely manner with minimum investment. This pilot study evaluated the usefulness of nationwide administrative databases (a hospital-based administrative database and an insurance claims database) for such passive surveillance of children hospitalized for VPDs using rotavirus gastroenteritis (RGE) as an example. Two rotavirus vaccines were launched in November 2011 and July 2012 in Japan. We assessed changes in the proportion of RGE hospitalizations among all-cause hospitalizations (N = 506,524) from the hospital database (April 2008-December 2016) and annual RGE hospitalization rates from the insurance claims database (January 2011-December 2016, n of beneficiaries = 460,585) in children aged <6 years. A total of 12,599 hospitalizations in 12,366 patients were associated with RGE from the hospital database. Similarly, 2038 patients had 2137 RGE-related hospitalizations from the insurance claims database. From 2009 to 2013, the proportion of RGE hospitalizations increased from 2.2% (95% confidence interval, 1.8-2.6) to 3.9% (3.7-4.0), then decreased and remained consistently low from 2014 (1.9% [1.8-2.0]) to 2016 (2.2% [2.1-2.3]). The RGE hospitalization rate decreased sharply in 2014, ranging between 2.85 and 3.52 during 2011-2013 to 0.97 (0.84-1.09) in 2014, and remained low through 2016 (1.18 [1.04-1.32]). In conclusion, we observed changes in RGE hospitalizations over time, without requiring additional data entry by clinicians. Nationwide administrative databases can be useful tools for passive surveillance of VPDs in Japan.

Association of severe abnormal behavior and acetaminophen with/without neuraminidase inhibitors.

BACKGROUND: Even though abnormal behavior related with influenza and neuraminidase inhibitors (NI) has been discussed, the risks of acetaminophen and co-administration of NI and acetaminophen have not been examined. This study assesses those risks. MATERIALS AND METHODS: All cases of patients with influenza who present with severe abnormal behavior are reported by physicians of all clinics and hospitals throughout Japan. The numbers of people diagnosed as having influenza, whether prescribed NI and acetaminophen or not, were extracted from the National Database of Electronic Medical Claims (NDBEMC). The study period was from September 2009 to March 2016. RESULTS: We found two consistent results among four combinations of age class and severity. The one was that patients who did not use NI or acetaminophen showed significantly higher incidence of abnormal behavior than zanamivir with acetaminophen, another one was that patients with oseltamivir only has higher incidence than zanamivir with acetaminophen. Concerning about acetaminophen, the use of it significantly decrease risk for severe and the most severe instances in 5-9-year-old patients with laninamivir and the severe instances in 10-19-year-old patients with zanamivir. DISCUSSION: We also demonstrated that acetaminophen alone or co-administered with NI does not seem to raise the risk of abnormal behavior in influenza patients.

Phylogeny and Immunoreactivity of Norovirus GII.P16-GII.2, Japan, 2016-17.

During the 2016-17 winter season in Japan, human norovirus GII.P16-GII.2 strains (2016 strains) caused large outbreaks of acute gastroenteritis. Phylogenetic analyses suggested that the 2016 strains derived from the GII.2 strains detected during 2010-12. Immunochromatography between 2016 strains and the pre-2016 GII.2 strains showed similar reactivity.

Severe abnormal behavior incidence after administration of neuraminidase inhibitors using the national database of medical claims.

An earlier study using the number of abnormal behaviors reported to the study group as the numerator and the number of influenza patient prescribed each neuraminidase inhibitor (NI) estimated by respective pharmaceutical companies found no significant difference among incidence rates of the most severe abnormal behaviors by type of NI throughout Japan. However, the dataset for the denominator used in that earlier study was the estimated number of prescriptions. In the present study, to compare the incidence rates of abnormal behavior more precisely among influenza patients administered several sorts of NI or administered no NI, we used data obtained from the National Database of Electronic Medical Claims (NDBEMC) as the denominator to reach a definitive conclusion. Results show that patients not administered any NI (hereinafter un-administered) or those administered peramivir sometimes showed higher risk of abnormal behavior than those administered oseltamivir, zanamivir, or laninamivir. However, the un-administered or peramivir patients were fewer than those taking other NI. Therefore, accumulation of data through continued research is expected to be necessary to reach a definitive conclusion about the relation between abnormal behavior and NI in influenza patients. Since severe abnormal behaviors with all types of NI or of un-administered patients have been reported, there are some risks in the administration of NI or even in un-administered cases. Therefore, we infer that the policy mandating package inserts in all types of NI.

[Evaluation of real-time surveillance of influenza incidence in Kawasaki City by comparison using the National Epidemiological Surveillance of Infectious Diseases].

Objectives　In Japan, nationwide data of the incidence of infectious diseases have been collected via the National Epidemiological Surveillance of Infectious Diseases (NESID) since 1981. In addition, since March 2014, Kawasaki City has operated its own real-time surveillance (RTS) system to collect data of the incidence of influenza from medical institutions across the city. This study aimed to describe the characteristics of the RTS system and compare the two surveillance systems to improve measures against infectious diseases in the future.Methods　NESID and RTS data from March 2014 to October 2017 were obtained from the Kawasaki City Institute for Public Health. First, the operating methodologies of the two surveillance systems were compared. Second, RTS data were used to analyze the daily epidemic curve, and then the daily number of influenza cases was converted into weekly data for comparison with NESID data. Pearson's correlation coefficients and 95% confidence intervals (CIs) were calculated. Correlations were also analyzed after data for the last and first weeks of each year were excluded because few hospitals remain open around the New Year holiday, resulting in a disproportionately large number of patients visiting the few institutions that remain open.Results　The NESID relies on data provided by a fixed number of medical institutions determined each fiscal year (mean: 56.0±4.2 institutions), while the number of institutions providing data for the RTS varies daily or monthly. In September 2017, 691 of the 1,032 eligible institutions (67.0%) were registered for the RTS. Pearson's correlation coefficient for the two surveillance systems was 0.975 (95%CI, 0.967-0.981); when data for the last and first week of each year were excluded, it was 0.989 (95%CI 0.986-0.992). In each of the three seasons that were investigated, an increase in the incidence of type A influenza preceded an increase in the incidence of type B influenza.Conclusion　The operating methodologies of the two surveillance systems differed; however, the results identified a strong correlation, confirming the reliability of the RTS. The RTS collects daily data by influenza type; therefore, it detects epidemic onsets at an earlier stage, facilitating more detailed epidemiological analysis, compared with that of the NESID. It is necessary to understand differences in the characteristics between two surveillance systems when we analyze influenza surveillance data.

A method for detecting rash and fever illness-associated viruses using multiplex reverse transcription polymerase chain reaction.

In this study, a new multiplex RT-PCR method for detecting various viral genes in patients with rash and fever illnesses (RFIs) was constructed. New primer sets were designed for detection of herpes simplex viruses 1 and 2 (HSV1 and 2), and Epstein-Barr virus (EBV). The newly designed and previously reported primer sets were used to detect 13 types of RFI-associated viruses by multiplex RT-PCR assay systems. Moreover, to eliminate non-specific PCR products, a double-stranded specific DNase was used to digest double-stranded DNA derived from the templates in clinical specimens. RFI-associated viruses were detected in 77.0% of the patients (97/126 cases) by the presented method, multiple viruses being identified in 27.8% of the described cases (35/126 cases). Detected viruses and clinical diagnoses were compatible in 32.5% of the patients (41/126 cases). Sensitivity limits for these viruses were estimated to be 101 -103 copies/assay. Furthermore, non-specific PCR products were eliminated by a double-stranded specific DNase with no influence on sensitivity. These results suggest that this method can detect various RFI-associated viruses in clinical specimens with high sensitivity and specificity.

Evaluation of streptococcal toxic shock-like syndrome caused by group B streptococcus in adults in Japan between 2009 and 2013.

Infection with Streptococcus agalactiae has long been recognized in infants. In recent years, S. agalactiae is an important cause of morbidity and mortality among adults and among those with underlying medical condition. Several cases of GBS infection and more fulminant disease similar to streptococcal toxic shock syndrome have recently been reported. We report here that 19 S. agalactiae strains were isolated from streptococcal toxic shock-like syndrome cases involving adult patients in Japan between 2009 and 2013. The average age of the patients was 66.3 years. At least one underlying disease was present in 47.4% (9/19) of the patients. The most prevalent serotype among these strains was Ib. All serotype Ib strains belonged to clonal complex 10 and were ciprofloxacin resistant. In contrast, all strains were susceptible to penicillin G, ampicillin, cefazolin, cefotaxime, imipenem, panipenem, and linezolid. The characteristic type distributions of streptococcal toxic shock-like syndrome isolates differed between isolates obtained from vaginal swabs of women and infants with invasive infections.

Association between first airborne cedar pollen level peak and pollinosis symptom onset: a web-based survey.

Cedar pollinosis in Japan affects nearly 25 % of Japanese citizens. To develop a treatment for cedar pollinosis, it is necessary to understand the relationship between the time of its occurrence and the amount of airborne cedar pollen. In the spring of 2009, we conducted daily Internet-based epidemiologic surveys, which included 1453 individuals. We examined the relationship between initial date of onset of pollinosis symptoms and daily amount of airborne cedar pollen to which subjects were exposed. Approximately 35.2 % of the subjects experienced the onset of pollinosis during a one-week interval in which the middle day coincided with the peak pollen count. The odds ratio for this one-week time interval was 4.03 (95 % confidence interval: 3.34-4.86). The predicted date of the cedar pollen peak can be used to determine the appropriate date for initiation of self-medication with anti-allergy drugs and thus avoid development of sustained and severe pollinosis.

[Frequency and Characterization of EPEC and EAggEC Isolated in Kawasaki City].

Thirty isolates of enteropathogenic Escherichia coli (EPEC) and 32 isolates of enteroaggregative E. coli (EAggEC) were isolated from 1,029 stool samples collected from Spring 2012 to December 2013 in Kawasaki city with the polymerase chain reaction (PCR) method targeting eae and aggR genes. Among the 30 EPEC and 32 EAggEC isolates, only 9 strains of EPEC and 8 strains of EAggEC were typed with the commercial O-antisera, whereas the majority of strains were untypable. However, several O-untypable EPEC and EAggEC strains were suggested to harbor the same O-antigen because of the detection of several examples of the same H-antigen. Analysis of the HEp-2 cell adherence test showed positive for only 2 strains (6.6%) of 30 EPEC isolates, meanwhile it showed positive for 16 strains (50.0%) of 32 EAggEC isolates. From these data, we concluded that EAggEC might be more virulent than EPEC, although both EAggEC and EPEC were isolated with almost similar rates from collected stool specimens.

Abnormal behavior during influenza in Japan during the last seven seasons: 2006-2007 to 2012-2013.

A few mortalities and cases of severe abnormal behavior have been reported after oseltamivir administration for influenza, thus increasing medical and public concerns regarding the drug's safety. We investigated the association between oseltamivir and abnormal behavior for seven years. All outpatient clinics and hospitals all over the country were requested to report severe abnormal behavior that could have resulted in a fatality if nobody intervened, such as abrupt running outside the home or intention of jumping off a building. The survey was performed prospectively between the 2007-2008 and 2012-2013 seasons, and retrospectively for the 2006-2007 season. As the result of the investigation, eight-hundred fifty-eight cases were reported and among of them 95.7% were positive by the influenza rapid diagnosis test. The epidemic curve of severe abnormal behavior showed a pattern similar to influenza-like illness. The same pattern was observed regardless of age group, gender, or timing of the incidents after waking. Consequently, specific association between the types of medications used or the types of antiviral and abnormal behavior was not observed clearly. The reported abnormal behaviors include fatal cases that would have died if nobody had stopped. This suggested that patients with influenza should be observed with caution for possible abnormal behavior whether taking oseltamivir or other neuraminidase inhibitor anti-influenza drugs.

Early therapy with neuraminidase inhibitors for influenza A (H1N1) pdm 2009 infection.

BACKGROUND: Neuraminidase inhibitors have been reported to decrease mortality in patients infected with influenza A (H1N1) pdm 2009 (H1N1 pdm09), but it is not clear whether they are effective against H1N1pdm09 in apparently healthy children. METHODS: The effect of early treatment with neuraminidase inhibitors on 70 otherwise healthy children with possible H1N1 pdm09 (pH1N1pdm09) infection was investigated. The children were simultaneously treated with a neuraminidase inhibitor (oseltamivir or zanamivir) and maoto, a Japanese traditional herbal medicine, which had been reported to be effective against seasonal influenza. Clinical severity was assessed using patient history, namely the worst values for clinical vital signs and laboratory data on admission. After refining these parameters with univariate, decision tree and multiple regression analysis, mean covariance structure equation analysis was used to investigate the association of estimated clinical severity to the selected parameters. RESULTS: Total path analysis using a Bayesian method indicated that the estimated clinical severity of pH1N1pdm09 was positively associated with maximum body temperature, pulse rate, respiration rate, duration necessary for defervescence, admission duration and log urinary ß2-microglobulin/creatinine level, and negatively associated with age and the presence and duration of treatment with the neuraminidase inhibitor in the outpatient clinic. CONCLUSIONS: This study provides the first clinical evidence that early treatment with neuraminidase inhibitors in outpatient clinic decreased the estimated clinical severity of pH1N1pdm09 in apparently otherwise healthy pediatric inpatients.

Internet survey of the influence of environmental factors on human health: environmental epidemiologic investigation using the web-based daily questionnaire for health.

With increasing Internet coverage, the use of a web-based survey for epidemiological study is a possibility. We performed an investigation in Japan in winter 2008 using the web-based daily questionnaire for health (WDQH). The WDQH is a web-based questionnaire survey formulated to obtain information about the daily physical condition of the general public on a real-time basis, in order to study correlations between changes in physical health and changes in environmental factors. Respondents were asked whether they felt ill and had specific symptoms including fever. We analysed the environmental factors along with the health conditions obtained from the WDQH. Four factors were found to influence health: minimum temperature, hours of sunlight, median humidity and weekday or holiday. The WDQH allowed a daily health survey in the general population in real time via the Internet.

Acute and Postacute Clinical Characteristics of Coronavirus Disease 2019 in Children in Japan.

BACKGROUND: The clinical features of coronavirus disease 2019 (COVID-19) in children have been changing because of the emergence and rapid spread of variants of concern (VOC). The increase in cases infected with VOC has brought concern with persistent symptoms after COVID-19 in children. This survey aimed to analyze the clinical manifestations and persistent symptoms of pediatric COVID-19 cases in Japan. METHODS: We analyzed the clinical manifestations of pediatric COVID-19 cases reported between February 2020 and April 2022 in Japan, using a dedicated database updated voluntarily by the members of the Japan Pediatric Society. Using the same database, we also analyzed persistent symptoms after COVID-19 in children who were diagnosed between February 2020 and November 2021. RESULTS: A total of 5411 and 1697 pediatric COVID-19 cases were included for analyzing clinical manifestations and persistent symptoms, respectively. During the Omicron variant predominant period, the percentage of patients with seizures increased to 13.4% and 7.4% in patient groups 1-4 and 5-11 years of age, respectively, compared with the pre-Delta (1.3%, 0.4%) or Delta period (3.1%, 0.0%). Persistent and present symptoms after 28 days of COVID-19 onset were reported in 55 (3.2%). CONCLUSIONS: Our survey showed that the rate of symptomatic pediatric COVID-19 cases increased gradually, especially during the Omicron variant predominant period, and a certain percentage of pediatric cases had persistent symptoms. Certain percentages of pediatric COVID-19 patients had severe complications or prolonged symptoms. Further studies are needed to follow such patients.

Association between seasonal influenza vaccination in 2008-2009 and pandemic influenza A (H1N1) 2009 infection among school students from Kobe, Japan, April-June 2009.

We assessed the effect of seasonal trivalent inactivated influenza vaccination (TIV) on pandemic influenza 2009 (pH1N1)-related illness from April to June 2009 among 2849 students (aged 12-18 years). TIV was associated with an increase in the frequency of pH1N1-related illness among subjects (adjusted odds ratio, 1.47; 95% confidence interval, 1.14-1.89). TIV during the 2008-2009 season increased the risk of pH1N1-related illness from April to June 2009.