Risk of death in old Japanese COVID-19 cases infected with the Omicron variant: a population-based study.

We assessed case fatality rates (CFRs) in cases aged ≥70 years in 10 Japanese prefectures (14.8 million residents) diagnosed between January 2022 and March 2023, when the Omicron variant was dominant in Japan. We selected incident reports on 283,052 study subjects from participating Public Health Centers adhering to the Infectious Diseases Control Law. Cases were passively followed up until the end of their isolation, date of death or 28 days after the COVID-19 diagnosis, whichever occurred first. We calculated age-standardized CFRs with 95% confidence intervals (CI) using the Japanese population aged 70-79, 80-89 and ≥90 in 2022 divided into 16 subgroups according to the period of COVID-19 diagnosis. The total overall CFR was 1.59% (95% CI 1.55-1.64); it ranged between 0.67% (95% CI 0.38-0.96, May 23-June 19) and 2.58% (95% CI 2.36-2.80, January 31-February 27). We observed three peaks of age-standardized CFRs paralleling the 6th, 7th and 8th endemic COVID-19 waves driven by Omicron in Japan (2.2% January 31-February 27, 1.0% July 18-August 14 and 1.6% December 26-January 22, 2023, respectively). Population-based CFRs for Omicron variant COVID-19 in Japanese aged ≥70 years remained <3% throughout the period January 2022-March 2023, including during three large endemic waves in this country.

Change over Time in the Risk of Death among Japanese COVID-19 Cases Caused by the Omicron Variant Depending on Prevalence of Sublineages.

To assess temporal changes to the risk of death in COVID-19 cases caused by the Omicron variant, we calculated age-standardized case fatality rates (CFR) in patients aged ≥40 years over nine diagnostic periods (3 January to 28 August 2022) in ten Japanese prefectures (14.8 million residents). Among 552,581 study subjects, we found that there were 1836 fatalities during the isolation period (up to 28 days from date of onset). The highest age-standardized CFR (0.85%, 95% confidence interval (CI):0.78-0.92) was observed in cases diagnosed in the second 4-week period (January 31 to February 27), after which it declined significantly up to the 6th 4-week period (0.23%, 95% CI: 0.13-0.33, May 23 to June 19). The CFR then increased again but remained at 0.39% in the eighth period (July 18 to August 28). The CFR in cases with the BA.2 or BA.5 sublineages in the age range 60-80 years was significantly lower than that with BA.1 infections (60 years: 0.19%, 0.02%, 0.053%, respectively; 70 years: 0.91%, 0.33%, 0.39%; ≥80 years: 3.78%, 1.96%, 1.81%, respectively). We conclude that the risk of death in Japanese COVID-19 patients infected with Omicron variants declined through February to mid-June 2022.

Improving Children's Sleep Habits Using an Interactive Smartphone App: Community-Based Intervention Study.

BACKGROUND: Sleep problems are quite common among young children and are often a challenge for parents and a hinderance to children's development. Although behavioral therapy has proven effective in reducing sleep problems in children, a lack of access to professionals who can provide effective support is a major barrier for many caregivers. Therefore, pediatric sleep experts have begun developing apps and web-based services for caregivers. Despite the substantial influence of cultural and familial factors on children's sleep, little effort has gone into developing cultural or family-tailored interventions. OBJECTIVE: This study aimed to examine the effectiveness of the interactive smartphone app "Nenne Navi," which provides culturally and family-tailored suggestions for improving sleep habits in young Japanese children through community-based long-term trials. The study also aimed to investigate the association between app-driven improvements in sleep and mental development in children. METHODS: This study adopted a community-based approach to recruit individuals from the Higashi-Osaka city (Japan) who met ≥1 of the following eligibility criteria for sleep problems: sleeping after 10 PM, getting <9 hours of nighttime sleep, and experiencing frequent nighttime awakenings. A total of 87 Japanese caregivers with young children (mean 19.50, SD 0.70 months) were recruited and assigned to the app use group (intervention group) or the video-only group (control group). Both groups received educational video content regarding sleep health literacy. The caregivers in the intervention group used the app, which provides family-tailored suggestions, once per month for 1 year. RESULTS: A total of 92% (33/36) of the caregivers in the app use group completed 1 year of the intervention. The participants' overall evaluation of the app was positive. The wake-up time was advanced (base mean 8:06 AM; post mean 7:48 AM; F1,65=6.769; P=.01 and sleep onset latency was decreased (base mean 34.45 minutes; post mean 20.05 minutes; F1,65=23.219; P<.001) significantly in the app use group at the 13th month compared with the video-only group. Moreover, multiple regression analysis showed that decreased social jetlag (ß=-0.302; P=.03) and increased sleep onset latency SD (ß=.426; P=.02) in children predicted a significant enhancement in the development of social relationships with adults. At 6 months after the completion of the app use, all the caregivers reported continuation of the new lifestyle. CONCLUSIONS: The present findings suggest that the app "Nenne Navi" has high continuity in community use and can improve sleep habits in young Japanese children and that interventions for sleep habits of young children may lead to the enhancement of children's social development. Future studies must focus on the effectiveness of the app in other regions with different regional characteristics and neuroscientific investigations on how changes in sleep impact brain development.

CMV DNA detection in dried blood spots for diagnosing congenital CMV infection in Japan.

Human cytomegalovirus (CMV) is a leading congenital infectious agent in developed countries. In the past, the incidence of congenital infection has been rather low in Japan because a high seroprevalence of CMV present in young women. However, this seroprevalence has been decreasing in recent years, so that the incidence of congenital CMV infection in Japanese neonates may increase and approach the level seen in other developed countries. The method was used for detecting CMV DNA reported by Barbi et al. [Barbi et al. (1996): Clin Diagn Virol 6:27-32] using a dried blood spot on filter paper, to diagnose congenital CMV infection in Japanese neonates. This method is effective and less laborious than virus isolation both for epidemiological studies and for identifying asymptomatic infected babies. Japanese neonates (1,176) were examined; two of who were asymptomatic were found to be infected.

Long-term hospitalization during pregnancy is a risk factor for vitamin D deficiency in neonates.

In order to examine the effects of long-term hospitalization during pregnancy on vitamin D metabolism in pregnant women and neonates, we measured the serum 25-hydroxyvitamin D (25OHD) levels in pregnant women, as well as measuring 25OHD levels in cord blood and breast milk. In pregnant women hospitalized for longer than 1 month, the serum 25OHD levels were decreased at delivery compared with those in control subjects (10.9 +/- 2.6 ng/l vs 19.5 +/- 4.9 ng/l; P < 0.01). Although the levels of 25OHD in the cord blood were not significantly different between the long-term hospitalized and control pregnant women in this study (9.36 +/- 1.7 ng/l vs 11.1 +/- 3.0 ng/l), the 25OHD concentrations in the cord blood were significantly lower than the maternal levels in both groups; the ratios of the levels in cord blood to sera in the long-term hospitalized women and control subjects were 82.1% and 60.3%, respectively. Long maternal hospitalization does not always cause neonatal vitamin D deficiency, but could be one of its major risk factors. Therefore, sufficient sunlight exposure and intake of sufficient vitamin D are considered to be important to prevent vitamin D deficiency in long-term hospitalized pregnant women as well as their babies.