Infectious disease activity during the COVID-19 epidemic in Japan: Lessons learned from prevention and control measures

Clinical efficacy of baloxavir marboxil versus oseltamivir in kidney transplant recipients with influenza

Kidney transplant recipients (KTRs) are at high risk for severe influenza and its complications. The effectiveness of baloxavir marboxil (hereafter baloxavir) in infected KTRs is still unknown. In this multicenter retrospective study conducted at eight Grade IIIA hospitals in China, KTRs diagnosed with influenza between October 2023 and March 2024 were enrolled. Of the 246 patients assessed, 117 met the inclusion criteria. There were 59 patients who received baloxavir and 58 patients who received oseltamivir. Patients receiving baloxavir had a longer time from symptom onset to treatment (≤48 h, 59.3% versus 79.3%; P = 0.019). Nevertheless, in comparison with those who were administered oseltamivir, they exhibited no statistically significant difference in time to alleviation of influenza symptoms [4 (2-6) versus 5 (3-7); P = 0.054], duration of fever [3 (2-4) versus 3 (2-4); P = 0.347], or viral clearance [6 (40.0%) versus 10 (58.8%); P = 0.479]. However, among patients who received antivirals within 48 h, baloxavir showed a significant correlation with fever resolution when compared with oseltamivir [2 (2, 3) versus 3 (2-4); P = 0.030]. Meanwhile, among patients who received antivirals after 48 h, a remarkable improvement of symptom alleviation in 5 days was observed in the baloxavir-treated group as compared to the oseltamivir-treated group [18 (75.0%) versus 2 (16.7%); P = 0.001]. In conclusion, compared to oseltamivir, patients may derive benefits from baloxavir treatment within 48 h, but especially after 48 h from symptom onset.IMPORTANCEThe multicenter cohort study is the first to compare the clinical efficacy of baloxavir with oseltamivir in influenza kidney transplant recipients (KTRs). The results showed that there were fewer influenza symptoms but a longer time for viral shedding in KTRs compared to non-immunosuppressed patients. No significant difference regarding time to alleviation of influenza symptoms and fever resolution between baloxavir and oseltamivir was found, which is consistent with CAPSTONE-1, whereas influenza KTRs who received baloxavir could have a shorter fever duration and symptom alleviation in 5 days compared to the oseltamivir-treated group. Our findings may provide guidance for influenza therapy in KTRs, solid organ transplant recipients, and immunocompromised patients.

Disease burden of rotavirus related diarrhea in children under 5 years in China: a meta-analysis

Rotavirus (RV) is a leading cause of severe diarrhea among children under five years of age in China. In this meta-analysis, we assessed the disease burden of RV-related diarrhea by analyzing 73 studies retrieved from the PubMed, Web of Science, China National Knowledge Infrastructure, and Wanfang databases (2013-2023). The incidence of RV-related diarrhea ranged from 0.637 /1000 to 31.46/1000 persons. The pooled RV positivity rate for the under-5 age group was 24.7% (95% confidence interval: 22.1-27.4), with higher positivity rates observed among inpatients compared to outpatients (24.1% vs. 22.2%). Notably, the RV positivity rate declined from 27.3 to 21.5% pre- and post- the RotaTeq® licensure and 28.8-22.5% following the COVID-19 pandemic. The G9P[8] genotype was predominant, accounting for 71.7% of the RV cases in the under-5 age group. Given the dynamic nature of the incidence rate of RV-related diarrhea and the prevalence of the G9P[8] genotype, it is imperative to enhance surveillance efforts targeting incidence of RV-related diarrhea and the circulating genotypes of rotavirus.

Healthcare utilization among Japanese older adults during later stage of prolonged pandemic

This study examines healthcare utilization patterns among Japan's older population (aged 75 and above) during a prolonged public health emergency, focusing on the later phase of the COVID-19 pandemic (November 2021-September 2022). This period was characterized by the Omicron variant, widespread vaccination coverage, and adapted public health measures. Using a comprehensive dataset of 189,841,257 medical claims linked with income tax records, we analyze how healthcare utilization correlates with public health measures, pandemic severity, and income levels. Our findings reveal distinct utilization patterns: moderate decreases in healthcare visits during periods of public health measures, with the association between pandemic severity and healthcare use varying based on whether these measures are in place. Despite fluctuations in visit frequency, healthcare costs remain stable, indicating consistent service intensity. While income-related differences in general healthcare access are modest, dental care shows more pronounced socioeconomic variations. These patterns suggest a transition from initial widespread healthcare avoidance to more stable healthcare engagement, indicating adaptation to prolonged crisis conditions. Our findings provide insights for maintaining healthcare access during extended public health emergencies, particularly in aging societies where balancing healthcare needs with public health measures is crucial.

Association between confirmed COVID-19 cases at hospitals and SARS-CoV-2 levels in municipal wastewater during the pandemic and endemic phases

COVID-19 is now considered endemic in many countries. On May 8, 2023, Japan reclassified COVID-19 from a pandemic to an endemic status, shifting surveillance from universal to sentinel reporting and transitioning the testing and treatment cost of COVID-19 from public funding to individual health insurance coverage. Restrictions on movement, events, and business hours were lifted, potentially increasing cases and complicating tracking. Monitoring hospital cases remains essential to protect high-risk inpatients from nosocomial infections. In this study, 13,812 COVID-19 cases in 12 hospitals were analyzed and the results revealed a strong correlation between SARS-CoV-2 levels in municipal wastewater and weekly new cases during both the pandemic period (February 15, 2021 - February 26, 2023; Pearson's r = 0.8321) and the endemic period (May 8, 2023 - October 1, 2023; Pearson's r = 0.7501). SARS-CoV-2 RNA levels in wastewater from municipal catchment areas showed a stronger correlation with the number of COVID-19 cases at hospitals than did RNA levels in wastewater from the catchment area where the hospitals are located. The difference in correlations was more pronounced during the endemic period. During the endemic period, measurements of SARS-CoV-2 RNA levels in samples obtained from larger sewersheds may be more effective in capturing the overall trends of COVID-19 cases in a region. In other words, during the endemic period, municipal wastewater surveillance may reflect the number of COVID-19 cases in hospitals. Even for facilities that do not monitor SARS-CoV-2 in their own hospital wastewater, publicly available municipal wastewater data can be used to estimate the number of COVID-19 cases in hospitals. Furthermore, COVID-19 infection control measures within hospitals can be evaluated by comparing the number of nosocomial infection patients based on the concentration of SARS-CoV-2 in municipal wastewater.

Immunity debt: Hospitals need to be prepared in advance for multiple respiratory diseases that tend to co-occur

As SARS-CoV-2 transitions from a pandemic to an endemic presence, a significant rise in respiratory diseases such as influenza and Mycoplasma pneumonia is challenging healthcare systems weakened by the impact of COVID-19. This commentary examines the global resurgence of respiratory pathogens, heightened by the post-pandemic "immunity debt", through an analysis of WHO surveillance data and national health reports. Findings reveal a substantial increase in respiratory illnesses, notably among children, compounded by a shortage of pediatricians and growing antimicrobial resistance. This underscores the need to improve hospital preparedness, optimize clinical responses, and enhance public health strategies to effectively navigate the impending peak of concurrent respiratory infections.

Alpha and Delta variants and vaccination effectiveness against severity in COVID-19 inpatients based on medical claims in Japan

Some mutated strains of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) presumably have high infectivity and pathogenicity. Using Japanese medical claims data, we assessed the pathogenicity of Alpha and Delta variants and vaccine effectiveness by severity. Inpatient records from the Medical Information Analysis Databank for the National Hospital Organization were used. Severity was defined as the proportion of inpatients using respiratory ventilators among inpatients with oxygen administration. We regressed severity and fatality on the proportion of patients with Alpha or Delta variant and on vaccination coverage, while allowing for some lag to reflect development from infection to hospitalization. We also examined results obtained when using data for all new inpatients, instead of inpatients with oxygen administration, as the denominator for severity. Estimation results were better when using severity defined by inpatients with oxygen administration as the denominator than when using all new inpatients. Especially for severity measures for inpatients 65 years old or older with oxygen administration, we confirmed an association of vaccination with lower severity and an association of Delta variant infection with high severity. Vaccines were most effective for people 65 years old or older. The age distributions of inpatients and confirmed patients were greater than for people younger than 65 years old. Vaccination reduced severity and fatality and Alpha and Delta variants might increase severity and fatality among inpatients 65 years old or older receiving oxygen therapy.

As the SARS-CoV-2 virus evolves, should Omicron subvariant BA.2 be subjected to quarantine, or should we learn to live with it?

It has been nearly 35 months since the COVID-19 outbreak. The pathogen SARS-CoV-2 has evolved into several variants. Among them, Omicron is the fifth variant of concern which have rapidly spread globally during the past 8 months. Omicron variant shows different characteristics from previous variants, which is highly infectious, highly transmissible, minimally pathogenic, vaccine and antibody tolerant; however, it is less likely to cause severe illness, resulting in fewer deaths. Omicron has evolved into five main lineages, including BA.1, BA.2, BA.3, BA.4, and BA.5. Before BA.5, Omicron BA.2 sublineage was the dominant strain all over the world for several months. The experience of prevention and treatment against BA.2 is worth studying and learning for overcoming other Omicron subvariants. Although the Omicron subvariant BA.2 is significantly less severe than that caused by ancestral strains, it is still far more dangerous than influenza, and its long-term sequelae are unknown. Effective treatments are currently limited; therefore, effective defense may be the key to controlling the epidemic today, rather than just "living with" the virus.

Malaria Publications before and during COVID-19 Pandemic: A Bibliometric Analysis

Coronavirus disease 2019 (COVID-19) has been reported to affect malaria intervention strategies, the suspension of malaria elimination programs, and the publication of malaria research. We compared differences in authorship, affiliations, countries, funding sources, article types, keywords, languages, and citations between studies published before and during the COVID-19 pandemic. The searches were performed online using the Scopus database on 8 April 2022. The searches were limited to two periods: before the COVID-19 pandemic (2018–2019) and during the COVID-19 pandemic (2020–2021). The information of authorship, affiliations, countries, funding sources, article types, keywords, languages, and citations between studies published before and during the COVID-19 pandemic were compared using frequency and percentage. The relationships between the most productive authors, countries, affiliations, journals, and frequently used keywords were visualized using the VOSviewer (version 1.6.18) software. A total of 2965 articles were identified in two periods and, among those, 1291 relevant studies were included. There was no difference in malaria publications before and during the COVID-19 pandemic (679 articles, 52.6% vs. 612 articles, 47.4%). Compared between the two periods, the preliminary trend of malaria publications in terms of authorship, affiliations, countries, funding sources, article types, keywords, languages, and citations were different. In conclusion, the current study showed the preliminary trends in malaria publications before and during the COVID-19 pandemic. The findings of this study would encourage researchers to perform a scoping review or systematic review to better understand the direction of malaria publications during the COVID-19 pandemic.

Dynamics of a stochastic SIRS epidemic model with standard incidence and vaccination

A stochastic SIRS epidemic model with vaccination is discussed. A new stochastic threshold $ R_0^s $ is determined. When the noise is very low ($ R_0^s < 1 $), the disease becomes extinct, and if $ R_0^s > 1 $, the disease persists. Furthermore, we show that the solution of the stochastic model oscillates around the endemic equilibrium point and the intensity of the fluctuation is proportional to the intensity of the white noise. Computer simulations are used to support our findings.

The role of influenza in the era of COVID-19: Can we forget it?

COVID-19 has been a topic of interest since a pandemic struck in 2019. The morbidity of influenza tended to decrease due to the measures to prevent COVID-19. Indeed, influenza seems to be "ignored" in this era of COVID-19. However, influenza has not disappeared from the scene. Presented here are two examples of recent influenza epidemics in China and Australia. Possible interactions between COVID-19 and influenza are discussed. Measures against COVID-19 may reduce contact with influenza, subsequently reducing adaptive immunity against influenza in the general population. Influenza might not be center stage right now, but insufficient adaptive immunity in the population may potentially trigger a future influenza pandemic. Coinfection with COVID-19 and influenza might potentially be a thorny problem. Hence, influenza cannot be ignored. Governments around the world should take measures to prepare for a possible influenza pandemic in the future.

The strategy behind Japan's response to COVID-19 from 2020-2021 and future challenges posed by the uncertainty of the Omicron variant in 2022

Japan has experienced five waves of the COVID-19 pandemic so far. Four states of emergency were declared, and the Tokyo 2020 Olympic (July 23-August 8, 2021) and Paralympic Games (August 24-September 5, 2021) were held during the fifth wave of the pandemic. Although a record 5,773 new cases were reported in Tokyo on August 13, the number abruptly decreased afterwards, and only 9 new cases were confirmed in Tokyo on November 1, 2021. The high vaccination rates (79.2% of the total population has received the first dose and 77.8% has received the second dose as of December 24, 2021) and behavioral changes (such as mask wearing rate in public places remains close to 100%) are considered to be important factors in curbing the spread of the virus. However, the new Omicron variant poses future challenges due to its uncertainty. A cumulative total of 231 cases of the Omicron variant were reported in Japan between November 30 and December 25, 2021. Preliminary data indicated that the Omicron variant could be more contagious but less deadly than the Delta variant. Since mankind may be forced to coexist with COVID-19, efforts such as vaccination campaigns will need to continue and behavioral changes will become increasingly important as the "new normal" to reduce population density and contact with people. This is evinced at least in Japan's successful practices in fighting the past five waves of the pandemic.

Public Health Measures During the COVID-19 Pandemic Reduce the Spread of Other Respiratory Infectious Diseases

Background: Public health measures (such as wearing masks, physical distancing, and isolation) have significantly reduced the spread of the coronavirus disease-2019 (COVID-19), but the impact of public health measures on other respiratory infectious diseases is unclear.

Objective: To assess the correlation between public health measures and the incidence of respiratory infectious diseases in China during the COVID-19 pandemic.

Methods: We collected the data from the National Health and Construction Commission in China on the number of patients with six respiratory infectious diseases (measles, tuberculosis, pertussis, scarlet fever, influenza, and mumps) from 2017 to 2020 and assessed the correlation between public health measures and the incidence of respiratory infectious diseases. Finally, we used the data of the six respiratory infectious diseases in 2021 to verify our results.

Results: We found public health measures significantly reduced the incidence of measles (p = 0.002), tuberculosis (p = 0.002), pertussis (p = 0.004), scarlet fever (p = 0.002), influenza (p = 0.034), and mumps (p = 0.002) in 2020, and prevented seasonal peaks. Moreover, the effects of public health measures were most marked during the peak seasons for these infections. Of the six respiratory infectious diseases considered, tuberculosis was least affected by public health measures.

Conclusion: Public health measures were very effective in reducing the incidence of respiratory infectious diseases, especially when the respiratory infectious diseases would normally have been at their peak.

Reduction of influenza in Osaka, Japan during the COVID-19 outbreak: a population-based ORION registry study

•

No reports using a population-based registry to evaluate COVID-19 impact on influenza

•

The Osaka Prefecture government created the ORION registry

•

ORION is the Osaka Emergency Information Research Intelligent Operation Network

•

ORION records emergency patients treated by emergency medical service (EMS) personnel

•

Number of influenza patients transported by EMS decreased during COVID-19 pandemic

Objectives

Methods

Results

Conclusions