What Proportion of Population has achieved Cellular Immunity against SARS-CoV-2 after Booster Vaccination: A Cross-sectional Study (preprint)

Background Booster vaccination reduces the incidence of severe cases and mortality of COVID-19, with cellular immunity playing an important role. However, little is known about what proportion of population has achieved cellular immunity after booster vaccination. Methods We conducted a Fukushima cohort database and assessed the humoral and cellular immunity in 2526 residents and HCWs in Fukushima Prefecture in Japan by continuous blood collection every 3 months since September 2021. We identified the proportion of people with induced cellular immunity after booster vaccination, using T-SPOT.COVID test, and analyzed their background characteristics. Results Among 1089 participants, 64.3 % (700/1089) had reactive cellular immunity after booster vaccination. Multivariable analysis revealed the following as independent predictors of reactive cellular immunity: age <40 years (adjusted odds ratio: 1.81, 95 % confidence interval: 1.19–2.75, p-value: 0.005), and adverse reactions after vaccination (1.92, 1.19-3.09, 0.007). Notably, despite IgG(S) and neutralizing antibody titers of ≥500 AU/mL, 33.9 % (349/1031) and 33.5 % (341/1017) of participants, respectively, did not have reactive cellular immunity. Conclusion This is the first study to evaluate cellular immunity at the population level after booster vaccination using T-SPOT.COVID test, however, with several limitations. Future studies will need to evaluate previously infected subjects and their T-cell subsets.

Difficulty in continuing home care after informal caregiver was exposed to the covid-19: a case report (preprint)

There are many challenges that can arise while providing home care to a terminally ill patient. Isolation of infected patients was used to prevent COVID-19 infection. In home care, where informal caregivers play an important role, such measures could result in the loss of caregivers.

End-of-life home care during the COVID-19 pandemic (preprint)

Patients and their families are discouraged from the restrictions on hospital visits for coronavirus Infection control. This separation might further deteriorate the mental health of both vulnerable patients and their family members. Home care could be a preferable solution to this problem.

Prevalence of novel coronavirus pneumonia in the early stage of transmission and responding strategies in Japan / 上海预防医学

Novel coronavirus pneumonia disease (COVID-19) caused by SARS-CoV-2 began to emerge in Wuhan, Hubei, China in December 2019. It is currently spreading globally including Japan. The COVID-19 case in Japan began to appear in middle January 2020 and continued to increase over time. The period from middle January to the end of February is considered to be the initial stage of domestic transmission in Japan. This article described the spread of 935 COVID-19 cases related to Japan by the end of February 2020, including the 15 infected Japanese returned from Wuhan, the 696 infected individuals in the large-scale cruise ship 'Diamond Princess' and the 224 infected individuals in Japan. This paper summarizes the measures to control the spread of SARS-CoV-2 in Japan, such as limiting RT-PCR detection for SARS-CoV-2, reducing the number of patients with mild illness who go to medical institutions unnecessarily, formulating guidelines for SARS-CoV-2 infection consultation, canceling large gatherings and temporarily closing schools. This paper further points out the problems encountered in the prevention and control of the spread of SARS-CoV-2 in Japan, such as the slow detection of RT-PCR, the risk of infection faced by medical staff, the regional differences in the domestic health care service system, the confusion of information disclosure and management. The above introduction as allows us to acquire a better understanding of the new coronavirus pneumonia in Japan and the world and may provide reference for the control the epidemic of COVID-19 in worldwide.