Development of a COVID-19 vaccine effectiveness and safety assessment system in Japan: The VENUS study.

BACKGROUND: There are currently no COVID-19 vaccine assessment systems in Japan that allow for the active surveillance of both vaccinated and unvaccinated persons. Herein, we describe the development of Japan's first COVID-19 vaccine effectiveness and safety assessment system with active surveillance capabilities. METHODS: The Vaccine Effectiveness, Networking, and Universal Safety (VENUS) Study was developed as a multi-source database that links four data types at the individual resident level: Basic Resident Register (base population information), Vaccination Record System (vaccination-related information), Health Center Real-time Information-sharing System on COVID-19 (HER-SYS; information on COVID-19 occurrence), and health care claims data (information on diagnoses, hospitalizations, diagnostic tests, and treatments). These data were obtained from four municipalities. Individual residents were linked across the data types using five matching algorithms based on names, birth dates, and sex; the data were anonymized after linkage. To ascertain the viability of the VENUS Study's database for COVID-19 vaccine assessments, we examined the trends in COVID-19 vaccinations, COVID-19 cases, and polymerase chain reaction (PCR) test numbers. We also evaluated the linkage rates across the data types. RESULTS: Our multi-source database was able to monitor COVID-19 vaccinations, COVID-19 cases, and PCR test numbers throughout the pandemic. Using the five algorithms, the data linkage rates between the COVID-19 occurrence information in the HER-SYS and the Basic Resident Register ranged from 85·4% to 91·7%. CONCLUSION: If used judiciously with an understanding of each data source's characteristics, the VENUS Study can provide a viable data platform that facilitates active surveillance and comparative analyses for population-based research on COVID-19 vaccine effectiveness and safety in Japan.

Survey of psychiatric symptoms among inpatients with COVID-19 using the Diagnosis Procedure Combination data and medical records in Japan.

Physical symptoms such as fatigue and muscle weakness, and psychiatric symptoms like depression and anxiety are considered as complications and sequelae of COVID-19. This epidemiological study investigated the actual status of psychiatric symptoms and disorders caused by COVID-19, from four major university hospitals and five general hospitals in Fukuoka Prefecture, Japan, having a population of 5 million. We conducted a survey of psychiatric disorders associated with COVID-19 using Diagnosis Procedure Combination (DPC) data and the psychiatric records of the hospitals. In the study period from January 2019 to September 2021, 2743 COVID-19 admissions were determined from DPC data across the nine sites. These subjects had significantly more anxiety, depression, and insomnia, and were receiving higher rates of various psychotropic medications than controls influenza and respiratory infections. A review of psychiatric records revealed that the frequency of organic mental illness with insomnia and confusion was proportional to the severity of COVID-19 infection and that anxiety symptoms appeared independent of infection severity. These results indicate that COVID-19 is more likely to produce psychiatric symptoms such as anxiety and insomnia than conventional infections.

Effectiveness of a Third Dose of COVID-19 mRNA Vaccine During the Omicron BA.1- and BA.2-Predominant Periods in Japan: The VENUS Study.

Background: Vaccine effectiveness against the severe acute respiratory syndrome coronavirus 2 Omicron BA.2 sublineage in Japan is unknown. We assessed the effectiveness of a third dose of COVID-19 mRNA vaccine compared with that of 2 doses. Methods: We performed a population-based cohort study using a municipality database located in the Chubu region of Japan during the Omicron BA.1- and BA.2-predominant periods (January 1-March 31, 2022 and April 1-27, 2022, respectively). We included residents aged ≥16 years who received a second vaccine dose at ≥14 days before the start of each period, regardless of the third dose. We compared the data at 14 days after the second and third dose and at 2-week intervals from 14 days to 10 weeks after the third dose using a Cox regression model. Vaccine effectiveness was defined as (1 - hazard ratio) × 100 (%). Results: In total, 295 705 and 288 184 individuals were included in the BA.1- and BA.2-predominant periods, respectively. The effectiveness of a third dose against infection was 62.4% and 48.1% in the BA.1- and BA.2-predominant periods, respectively. Vaccine effectiveness at 2-3 weeks and ≥10 weeks after the third dose decreased from 63.6% (95% confidence interval [CI], 56.4-69.5%) to 52.9% (95% CI, 41.1-62.3%) and from 54.5% (95% CI, 3.0-78.7%) to 40.1% (95% CI, 15.1-57.7%) in the BA.1- and BA.2-predominant periods, respectively. Conclusions: A third dose was moderately effective against BA.1 and BA.2 sublineages, but its effectiveness decreased by approximately 10% age points from 2-3 weeks to ≥10 weeks after the third vaccination.

Effectiveness of messenger RNA vaccines against infection with SARS-CoV-2 during the periods of Delta and Omicron variant predominance in Japan: the Vaccine Effectiveness, Networking, and Universal Safety (VENUS) study.

OBJECTIVES: We aimed to evaluate COVID-19 messenger RNA vaccine effectiveness during the Delta- and Omicron-predominant periods in Japan. METHODS: We conducted a population-based cohort study among individuals aged 16-64 years during two periods: the Delta-predominant period (July 1-December 31, 2021) and the Omicron-predominant period (January 1-March 29, 2022). RESULTS: When comparing individuals who were vaccinated with those who were unvaccinated, the effectiveness of a second dose against symptomatic infection was 89.8% (95% confidence interval [CI]: 80.5-94.7%) during the Delta-predominant period and 21.2% (95% CI: 11.0-30.3%) during the Omicron-predominant period. The effectiveness of a third dose against symptomatic infection was 71.8% (95% CI: 60.1-80.1%) during the Omicron-predominant period. CONCLUSION: Vaccine effectiveness against symptomatic infection decreased during the Omicron-predominant period but was maintained by a third dose.

Acute and delayed psychiatric sequelae among patients hospitalised with COVID-19: a cohort study using LIFE study data.

Background: Characterising the psychiatric sequelae of coronavirus disease 2019 (COVID-19) can inform the development of long-term treatment strategies. However, few studies have examined these sequelae at different time points after COVID-19 infection. Aims: The study aimed to investigate the incidences and risks of acute and delayed psychiatric sequelae in patients hospitalised with COVID-19 in Japan. Methods: This retrospective cohort study was conducted using a database comprising healthcare claims data from public health insurance enrollees residing in a Japanese city. We analysed a primary cohort comprising patients hospitalised with COVID-19 between March 2020 and July 2021 and two control cohorts comprising patients hospitalised with influenza or other respiratory tract infections (RTI) during the same period. We calculated the incidences of acute (1-3 months after infection) and delayed (4-6 months after infection) psychiatric sequelae. These sequelae were identified using diagnosis codes and categorised as mood/anxiety/psychotic disorder, mood disorder, anxiety disorder, psychotic disorder or insomnia. Multivariable logistic regression models were used to estimate the odds ratios (ORs) of psychiatric sequelae occurrence after COVID-19 infection compared with influenza and other RTI. Results: The study population with acute psychiatric sequela consisted of 662 patients with COVID-19, 644 patients with influenza, and 7369 patients with RTI who could be followed for 3 months; the study population with delayed psychiatric sequelae consisted of 371 patients with COVID-19, 546 patients with influenza, and 5397 patients with RTI who could be followed for 6 months. In the analysis of acute psychiatric sequelae, COVID-19 had significantly higher odds of mood/anxiety/psychotic disorder (OR: 1.39, p=0.026), psychotic disorder (OR: 2.13, p<0.001), and insomnia (OR: 2.59, p<0.001) than influenza, and significantly higher odds of insomnia (OR: 1.44, p=0.002) and significantly lower odds of anxiety disorder (OR: 0.56, p<0.001) than other RTI. In the analysis of delayed psychiatric sequelae, COVID-19 had significantly higher odds of psychotic disorder (OR: 2.25, p=0.007) than influenza, but significantly lower odds of anxiety disorder (OR: 0.55, p=0.011) than other RTI. Conclusions: COVID-19 was generally associated with an increased risk of psychiatric sequelae occurring within 3 months after infection, but had a lower risk of new psychiatric sequelae developing 4-6 months after infection.