Face mask use is a critical behavior to prevent the spread of SARS-CoV-2. We aimed to evaluate the association between social integration and face mask use during the COVID-19 pandemic in a random sample of households in Utsunomiya City, Greater Tokyo, Japan. Data included 645 adults in the Utsunomiya COVID-19 seROprevalence Neighborhood Association (U-CORONA) study, which was conducted after the first wave of the pandemic, between 14 June 2020 and 5 July 2020, in Utsunomiya City. Social integration before the pandemic was assessed by counting the number of social roles, based on the Cohen’s social network index. Face mask use before and during the pandemic was assessed by questionnaire, and participants were categorized into consistent mask users, new users, and current non-users. Multinomial logistic regression analysis was used to examine the association between lower social integration score and face mask use. To account for possible differential non-response bias, non-response weights were used. Of the 645 participants, 172 (26.7%) were consistent mask users and 460 (71.3%) were new users, while 13 (2.0%) were current non-users. Lower social integration level was positively associated with non-users (RRR: 1.76, 95% CI: 1.10, 2.82). Social integration may be important to promote face mask use.

Background: The number of confirmed cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in Japan are substantially lower in comparison to the US and UK, potentially due to the under-implementation of polymerase chain reaction (PCR) tests. Studies reported that more than half of the SARS-CoV-2 infections are asymptomatic, confirming the importance for conducting seroepidemiological studies. Although the seroepidemiological studies in Japan observed a reported prevalence of 0.10% in Tokyo, 0.17% in Osaka, and 0.03% in Miyagi, sampling bias was not considered. The study objective was to assess the seroprevalence of SARS-CoV-2 in a random sample of households in Utsunomiya City in Tochigi Prefecture, Greater Tokyo, Japan. Methods: We launched the Utsunomiya COVID-19 seROprevalence Neighborhood Association (U-CORONA) Study to assess the seroprevalence of COVID-19 in Utsunomiya City. The survey was conducted between 14 June 2020 and 5 July 2020, in between the first and second wave of the pandemic. Invitations enclosed with a questionnaire were sent to 2,290 people in 1,000 households randomly selected from Utsunomiya basic resident registry. Written informed consent was obtained from all participants. The level of IgG antibodies to SARS-CoV-2 was assessed by chemiluminescence immunoassay analysis. Results: Among 2,290 candidates, 753 returned the questionnaire and 742 received IgG tests (32.4 % participation rate). Of the 742 participants, 86.8% were 18 years or older, 52.6% were women, 71.1% were residing within 10 km from the test clinic, and 89.2% were living with another person. The age and sex distribution, distance to clinic and police district were similar with those of non-participants, while the proportion of single-person households was higher among non-participants than participants (16.2% vs. 10.8%). We confirmed three positive cases through quantitative antibody testing. No positive cases were found among the people who live in the same household as someone with positive. All cases were afebrile. The estimated unweighted and weighted prevalence of SARS-CoV-2 infection were 0.40% (95% confidence interval: 0.08-1.18%) and 1.23% (95% confidence interval: 0.17-2.28%), respectively. Conclusion: This study suggests the importance of detecting all cases using PCR or antigen testing, not only at a hospital, but also in areas where people assemble. Further prospective studies using this cohort are needed to monitor SARS-CoV-2 antibody levels.

Objective: Coronavirus disease 2019 (COVID-19) has spread worldwide, including Japan. However, little is known about the clinical symptoms which discriminate between COVID-19 and non-COVID-19 among outpatients in general practitioner clinics, which is important for efficient case detection. The aim of this study was to investigate the clinical symptoms to discriminate between COVID-19 and non-COVID-19 cases among outpatients in general practitioner clinics during the second wave of the COVID-19 pandemic in Japan in August 2020. Methods: The records of 360 patients who visited a clinic with suspicion of infectious disease and underwent COVID-19 PCR test between 1 and 14 August 2020 were used. The patients filled out a questionnaire on possible clinical symptoms and transmission routes. Multivariate logistic regression was used to investigate the association between clinical symptoms and COVID-19 status. Results: COVID-19-positive patients were 17 (4.7%). Multiple logistic regression analyses showed that anosmia (odds ratio (OR), 25.94 95% confidence interval (CI), 7.15–94.14; p < 0.001), headache (OR, 3.31 95% confidence interval (CI), 0.98–11.20; p = 0.054), sputum production (OR, 3.32 CI, 1.01–10.90; p = 0.048) and history of visiting an izakaya or bar (OR, 4.23 CI, 0.99–18.03; p = 0.051) were marginally significantly associated withbeing COVID-19 positive. This model showed moderate predictive power (area under receiver operating characteristic curve = 0.870 CI, 0.761 to 0.971). Conclusions: We found that anosmia, headache, sputum production, history of visiting an izakaya or bar were associated with COVID-19, which can be used to detect patients with COVID-19 in out-patient clinics in Japan. The findings of this study need to be verified in other clinics and hospitals in Japan and other countries with universal healthcare coverages.

BACKGROUND Persistent COVID-19 in immunocompromised patients, such as those with B-cell depletion or hematologic malignancies, is an important clinical challenge. Clinically, cases that do not respond to guideline-based antivirals, such as molnupiravir, remdesivir, and nirmatrelvir/ritonavir, are occasionally encountered, but effective therapeutic alternatives remain scarce. We report a case of persistent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection unresponsive to guideline-based antivirals, for which the traditional Japanese herbal medicine Mao-to (Ma-huang-tang) led to clinical improvement. CASE REPORT A 62-year-old man, who underwent treatment for follicular lymphoma with anti-cluster of differentiation-20 antibody and achieved remission, developed persistent SARS-CoV-2 infection. Despite 1 course of molnupiravir and nirmatrelvir/ritonavir each and multiple courses of remdesivir and corticosteroids each, SARS-CoV-2 infection persisted for over 2 months. Following these treatments, the SARS-CoV-2 polymerase chain reaction cycle threshold (Ct) value was 27.6, indicating active COVID-19. Given the lack of further treatment options and clinical stability, Mao-to (Ma-huang-tang), a Japanese herbal medicine ("Kampo"), was then administered as a commercially available extract granule (2.5 g, 3 times daily) for 14 days. The SARS-CoV-2 polymerase Ct value improved to 41, suggesting a marked reduction in viral load, with improved clinical symptoms. CONCLUSIONS Mao-to may offer a cost-effective adjunctive option for persistent COVID-19 in immunocompromised patients who fail to respond to conventional therapies. In addition, 14 days of Mao-to treatment cost approximately 1200 JPY (USD $8), significantly less than extended courses of standard antivirals. This case suggests the potential utility of traditional herbal medicine in managing persistent SARS-CoV-2 infections when conventional therapies fail.