The Proportion of Long-term Response to Anti-N IgG Antibody after 12 Months for COVID-19 Subclinical Infections and a Longitudinal Survey for COVID-19 Subclinical Infections in 2021.

Objective To examine the continuation of antibody prevalence status after 12 months and background factors in antibody-positive subjects following asymptomatic infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Methods We initially determined the SARS-CoV-2 anti-nucleocapsid protein immunoglobulin G (anti-N IgG) antibody prevalence in 1,603 patients, doctors, and nurses at 65 medical institutions in Kanagawa Prefecture, Japan. We then obtained consent from 33 of the 39 subjects who tested positive and performed follow-up for 12 months. Results Follow-up for up to 12 months showed that a long-term response of the anti-N IgG antibody could be detected in 6 of the 33 participants (18.2%). The proportions with hypertension, using an angiotensin-receptor blocker, and without a drinking habit were higher among the participants with a long-term anti-N IgG antibody response for up to 12 months than among those without a long-term antibody response. Conclusions The proportion of individuals with subclinical COVID-19 who continuously had a positive result for the anti-N IgG antibody at 12 months was low.

Impact of a telemedicine system on work burden and mental health of healthcare providers working with COVID-19: a multicenter pre-post prospective study.

Background: The coronavirus disease 2019 (COVID-19) pandemic impacts not only patients but also healthcare providers. This study seeks to investigate whether a telemedicine system reduces physical contact in addressing the COVID-19 pandemic and mitigates nurses' distress and depression. Methods: Patients hospitalized with COVID-19 in 4 hospitals and 1 designated accommodation measured and uploaded their vital signs to secure cloud storage for remote monitoring. Additionally, a mat-type sensor placed under the bed monitored the patients' respiratory rates. Using the pre-post prospective design, visit counts and health care providers' mental health were assessed before and after the system was introduced. Results: A total of 100 nurses participated in the study. We counted the daily visits for 48 and 69 patients with and without using the telemedicine system. The average patient visits were significantly less with the system (16.3 [5.5-20.3] vs 7.5 [4.5-17.5] times/day, P = .009). Specifically, the visit count for each vital sign assessment was about half with the telemedicine system (all P < .0001). Most nurses responded that the system was easy to use (87.1%), reduced work burden (75.2%), made them feel relieved (74.3%), and was effective in reducing the infection risk in hospitals (79.1%) and nursing accommodations (95.0%). Distress assessed by Impact of Event Scale-Revised and depression by Patient Health Questionnaire-9 were at their minimum even without the system and did not show any significant difference with the system (P = .72 and .57, respectively). Conclusions: Telemedicine-based self-assessment of vital signs reduces nurses' physical contact with COVID-19 patients. Most nurses responded that the system is easy and effective in reducing healthcare providers' infection risk.

Study on Continuation of Antibody Prevalence Six Months after Detection of Subclinical Severe Acute Respiratory Syndrome Coronavirus 2 Infections.

Objective To examine the continuation of antibody prevalence and background factors in antibody-positive subjects after asymptomatic infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Methods A study was carried out to investigate the SARS-CoV-2 antibody (IgG) prevalence. SARS-CoV-2 antibodies (IgG) were measured and analyzed with immunochromatographic tests. Patients Among 1,603 subjects, comprising patients, physicians, and nurses at 65 medical institutes in Kanagawa, Japan, 39 antibody-positive subjects received follow-up for 6 months. Results Of the 33 subjects who consented to the follow-up (23 patients and 10 medical professionals), continued positivity of IgG antibodies was confirmed in 11 of 32 cases (34.4%) after 2 months, 8 of 33 (24.2%) after 4 months, and 8 of 33 (24.2%) after 6 months. A significant difference was found in the sleeping time, drinking habits, hypertension, and use of angiotensin-receptor blockers on comparing subject background characteristics among three groups: patients with antibody production that continued for six months after the first detection of positivity, patients in whom antibody production stopped at four months, and patients in whom antibody production stopped at two months. Conclusion The continuation rate of IgG antibody prevalence was 24.2% at 6 months after the first detection of antibody positivity in cases with asymptomatic coronavirus disease 2019 (COVID-19) infections. This percentage is low compared with the antibody continuation rate in patients who have recovered from symptomatic COVID-19 infection.

Survey of the current status of subclinical coronavirus disease 2019 (COVID-19).

OBJECTIVES: We investigated relationships between subclinical COVID-19 (coronavirus disease 2019) and background factors. METHODS: We determined SARS-CoV-2 antibody (IgG) prevalence in 1603 patients, doctors, and nurses in 65 medical institutions in Kanagawa Prefecture, Japan and investigated their background factors. Antibodies (IgG) against SARS-CoV-2 were analyzed by Immunochromatographic test. RESULTS: The 39 subjects (2.4%) were found to be IgG antibody-positive: 29 in the patient group (2.9%), 10 in the doctor/nurse group (2.0%), and 0 in the control group. After adjustment for age, sex, and the antibody prevalence in the control group, antibody prevalence was 2.7% in the patient group and 2.1% in the doctor/nurse group. There was no significant difference between the antibody-positive subjects and the antibody-negative subjects in any background factors investigated including overseas travel, contact with overseas travelers, presence/absence of infected individuals in the living area, use of trains 5 times a week or more, BCG vaccination, and use of ACE inhibitor and ARB. CONCLUSIONS: Antibody prevalence in the present survey at medical institution is higher than that in Tokyo and in Osaka measured by the government suggesting that subclinical infections are occurring more frequently than expected. No background factor that influenced antibody-positive status due to subclinical infection was identified.

[Clinical Study of 45 Cases of COVID-19 and a Consideration of Severity Classification by the Kanagawa Model]

The outbreak of the novel coronavirus infection in Wuhan City, Hubei Province, China, in December 2019, has spread rapidly around the world, and the number of cases with no apparent route of transmission (cases of community transmission) is increasing in Japan. We have encountered 45 cases of COVID-19 infection, including 33 male and 12 female patients. The average age of the patients was 50.6 years. The symptoms were fever in 39 (86.7%) cases, cough in 33 (73.3%) cases, malaise in 24 (53.3%) cases, and diarrhea in 5 (11.1%) cases. In addition, according to the Kanagawa-model severity classification constructed by Kanagawa Prefecture to avoid collapse of the medical infrastructure caused by a sudden increase in patients, 30 cases were classified as having mild disease, 14 as having moderately severe disease, and 1 as having severe disease. Of the 30 patients with mild disease, 1 (3.3%) showed deterioration to moderately severe disease during the clinical course, and of the 14 patients with moderately severe disease, 6 (42.9%) showed deterioration to severe disease. The findings in respect of the subsequent clinical course of the patients suggest that the Kanagawa-model severity classification is a reasonable classification for satisfactory triage of patients.