Selecting coronavirus disease 2019 patients with negligible risk of progression: early experience from non-hospital isolation facility in Korea

Features of antibody responses after SARS-COV-2 infection in healthcare workers in the first wave of COVID-19 pandemic in Mexico City

Objective

To investigate the antibody response to SARS-CoV-2 and identify associated factors in frontline and second-line healthcare workers (HCWs) at a large hospital in Mexico City during the first wave of COVID-19 pandemic.

Methods

This was a cross-sectional study of HCWs returning to work following mandatory isolation after recovering from COVID-19. Immunoglobulin (Ig) M and IgG antibodies elicited by SARS-CoV-2 were semiquantitatively measured using densitometric analysis of band intensities in lateral flow assay (LFA) devices. The mean pixel intensity (dots-per-inch [dpi]) of each band on the LFA was considered a measure of antibody titre.

Results

Of the 111 HCWs involved in the study, antibody responses were detected in 73/111 (66%) participants. Severe COVID symptoms was associated with old age. No differences in IgM intensity were observed between men and women, but IgG intensity was significantly higher in men than in women. Second-line HCWs produced a higher IgG intensity than firstline HCWs. The IgG intensity was high in severe cases.

Conclusions

For HCWs who may acquire SARS-CoV-2 infection, it is necessary to establish a routine program for detection of the virus to avoid risk of infection and spread of COVID-19.

Risk factors for the deterioration of patients with mild COVID-19 admitted to a COVID-19 community treatment center

Background: The rapid increase in the number of coronavirus disease (COVID-19) patients led to the operation of COVID-19 facilities for patients with mild COVID-19 in South Korea. We analyzed the correlation and effect of risk factors associated with the worsening of patients with mild COVID-19 leading to their transfer from a community treatment center to a hospital.Methods: This retrospective cohort observational study included 1,208 COVID-19 patients with mild symptoms who were admitted to the Namsan Community Treatment Center between June 2020 and January 2021. A chi-square test was performed to examine the differences in the transfer rate by age, sex, nationality, presence of symptoms at admission, and season, and a multivariable logistic regression analysis was performed to examine the association of variables to the hospitalization rate.Results: Of the 1,208 patients, 212 (17.5%) were transferred to a hospital due to clinical deterioration. Increasing odds of hospital transfer were associated significantly with higher age and presentation in autumn, whereas sex and symptomatic illness at admission did not show a statistically significant association.Conclusion: The findings indicate the importance of the initial risk classification of COVID-19 patients based on thorough assessment and close monitoring, timely allocation of appropriate resources to high-risk groups that are likely to develop severe disease, and reduction of medical resource wastage and limiting of administrative force to ensure that patients receive the best treatment.

Persistent Antibody Responses up to 18 Months after Mild SARS-CoV-2 Infection

Background

Humoral immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may wane rapidly in persons recovered from mild coronavirus disease 2019 (COVID-19), but little is known about the longevity.

Methods

Serum samples were obtained 8, 12, and 18 months after infection from 20 patients with mild COVID-19. The binding activities of serum antibodies (IgA, IgG, and IgM) against SARS-CoV-2 antigens of the Wuhan-1 reference strain (wild-type) and the B.1.1.7, P.1, B.1.167.2, and B.1.1.529 variants were measured by enzyme-linked immunosorbent assays. Neutralizing antibody titers were measured using a cytopathic effect-based live virus neutralization assay.

Results

Serum IgA and IgG antibodies against spike or receptor-binding domain (RBD) protein of wild-type SARS-CoV-2 were detected for up to 18 months, and neutralizing antibodies persisted for 8 to 18 months after infection. However, any significant antibody responses against RBD proteins of SARS-CoV-2 variants were not observed, and median neutralizing antibody titers against the Delta variant at 8, 12, and 18 months were 8–11 fold lower than against wild-type viruses (P < .001).

Conclusions

Humoral immunity persisted for up to 18 months after SARS-CoV-2 infection in patients with mild COVID-19. Humoral immune activity against more recently circulating variants, however, was reduced in this population.

Kinetics of Neutralizing Antibody Responses Against SARS-CoV-2 Delta Variant in Patients Infected at the Beginning of the Pandemic

We investigated the kinetics of the neutralizing antibody responses to the severe acute respiratory syndrome-coronavirus-2 delta variant over the course of 1 year in 16 patients infected at the beginning of the pandemic. In patients with severe disease, neutralizing responses to the delta variant were detectable, albeit at lower levels than responses to the wild type. Neutralizing responses to the delta variant were undetectable, however, in asymptomatic persons. This finding implies that the vaccination strategy for persons with past natural infection should depend on the severity of the previous infection.

Coronavirus Disease 2019 Patients with Mild Symptoms or without Symptom Using Residential Treatment Center Model

Background

The rapid rise in coronavirus disease worldwide has drastically limited the availability of hospital facilities for patients. Residential treatment centers were opened in South Korea for the admission of asymptomatic or patients with mild symptoms. This study discusses the appropriateness of the admission criteria set by the centers in a pandemic situation, the prioritization of patients for admission, and ways to minimize the risk of self-isolation.

Methods

A total of 217 low-risk patients (n=217) were admitted to the Nowon Residential Treatment Center between August 22 and October 14, 2020. The following criteria were met at the time of admission: patients (1) were asymptomatic or had mild symptoms, (2) had either a controlled or no underlying chronic disease, and (3) did not need oxygen treatment. Among them, 202 patients who were eligible for inclusion in the study were retrospectively investigated through periodic interviews.

Results

Of the 202 patients, 153 satisfied the criteria for symptomatic isolation standards, and 25 for asymptomatic isolation standards. The clinical conditions of 24 patients were aggravated, and these patients were transferred to other hospitals, among which 12 had persistent fever and 13 were suffering dyspnea with oxygen saturation (SpO₂) <95%.

Conclusion

In the event of another large-scale epidemic, it would be appropriate to prioritize accommodating patients who are elderly or have underlying diseases and self-isolate young patients with no underlying diseases and provide them with SpO₂ meters and thermometers to self-measure SpO₂ and body temperature.

Management of the COVID-19 Pandemic in the Republic of Korea from the Perspective of Governance and Public-Private Partnership

The government of the Republic of Korea (ROK) has established relevant laws and a master plan for infectious disease control and prevention based on their experiences with past epidemics. In addition, the Ministry of Health and Welfare has designed a standard manual for risk management that involves pan-governmental crisis management systems. This national infectious disease management system is constantly being supplemented and developed in face of infectious disease-related crises. In this study, we set out to present directions for infectious disease prevention and flow of management and governance between central and local governments to ensure systematic quarantine activities in the ROK. During the coronavirus disease 2019 (COVID-19) pandemic, public-private partnerships have been established to collect, provide, process, and disseminate information for effective quarantine. This has enabled the development and rapid approval of test kits, the tracking of cases, and the allocation of appropriate resources for patient treatment. Additionally, the Infectious Disease Control Agency has actively utilized information and communication technology platforms to disclose information necessary in real-time for COVID-19 quarantine and management. Overall, these efforts have played an important role in epidemiological investigations, patient management, and quarantine in the early stages of the COVID-19 pandemic.

Predication of oxygen requirement in COVID-19 patients using dynamic change of inflammatory markers: CRP, hypertension, age, neutrophil and lymphocyte (CHANeL)

The objective of the study was to develop and validate a prediction model that identifies COVID-19 patients at risk of requiring oxygen support based on five parameters: C-reactive protein (CRP), hypertension, age, and neutrophil and lymphocyte counts (CHANeL). This retrospective cohort study included 221 consecutive COVID-19 patients and the patients were randomly assigned randomly to a training set and a test set in a ratio of 1:1. Logistic regression, logistic LASSO regression, Random Forest, Support Vector Machine, and XGBoost analyses were performed based on age, hypertension status, serial CRP, and neutrophil and lymphocyte counts during the first 3 days of hospitalization. The ability of the model to predict oxygen requirement during hospitalization was tested. During hospitalization, 45 (41.8%) patients in the training set (n = 110) and 41 (36.9%) in the test set (n = 111) required supplementary oxygen support. The logistic LASSO regression model exhibited the highest AUC for the test set, with a sensitivity of 0.927 and a specificity of 0.814. An online risk calculator for oxygen requirement using CHANeL predictors was developed. “CHANeL” prediction models based on serial CRP, neutrophil, and lymphocyte counts during the first 3 days of hospitalization, along with age and hypertension status, provide a reliable estimate of the risk of supplement oxygen requirement among patients hospitalized with COVID-19.

Antibody Responses One Year after Mild SARS-CoV-2 Infection

Understanding the long-term kinetics of antibodies in coronavirus disease 2019 (COVID-19) is essential in interpreting serosurvey data. We investigated the antibody response one year after infection in 52 mildly symptomatic patients with severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection, using three commercial immunoassays and a surrogate virus neutralization test (sVNT) kit. Anti-N pan-immunoglobulin (Ig), anti-S IgG, and anti-S1 IgG were detected in 43 (82.7%), 44 (84.6%), and 30 (57.7%), respectively. In 49 (94.2%), the antibody could be detected by either anti-N pan-Ig or anti-S IgG assay. In the sVNT, 30 (57.7%) had positive neutralizing activity. Despite waning immunity, SARS-CoV-2 antibodies can be detected up to one year after infection, even in mild COVID-19 patients.

Clinical Characteristics of COVID-19: Risk Factors for Early Oxygen Requirement after Hospitalization

BACKGROUND

Some coronavirus disease 2019 (COVID-19) patients initially present with early oxygen demand, requiring more medical resources, and some develop severe conditions, while others worsen later in their clinical course. Whether the nature of the two groups is the same but in the spectrum of different diagnostic time points is not certain.

METHODS

Hospitalized COVID-19 patients who needed oxygen therapy from February to November 2020 were included in the study. The patients were divided into early and late groups based on the time when the oxygen requirement occurred. Basic and epidemiologic characteristics were compared. Clinical variables were analyzed in both groups.

RESULTS

A total of 164 patients needed oxygen therapy, 94 of whom were in the early group and 70 of whom were in the late group. The early and late groups had similar baseline characteristics except age (median age, 73 vs. 67 years), uncertain exposure history (50% vs. 31.4%) and the time from the onset of illness to admission (median, 5 vs. 2 days). Multivariate analysis showed that age > 65 years (OR, 4.65), symptom onset > 5 days (OR, 9.13) and several clinical manifestations, such as febrile sensation (OR, 6.01), dyspnea (OR, 30.0), C-reactive protein > 1 mg/dL (OR, 7.87) and chest X-ray abnormality (OR, 8.15), were predictive factors in the early group. The early group required more intensive care such as mechanical ventilation care, extracorporeal membrane oxygenation and death (29.8% vs. 14.3%, P = 0.002).

CONCLUSION

Older age, especially > 65 years, and a delay of over 5 days from the onset of illness to admission were associated with early oxygen demand in COVID-19 patients. Interventions for earlier diagnosis of elderly people may benefit clinical outcomes.

Antibody Responses 8 Months after Asymptomatic or Mild SARS-CoV-2 Infection

Waning humoral immunity in coronavirus disease patients has raised concern over usefulness of serologic testing. We investigated antibody responses of 58 persons 8 months after asymptomatic or mildly symptomatic infection with severe acute respiratory syndrome coronavirus 2. For 3 of 4 immunoassays used, seropositivity rates were high (69.0%–91.4%).

Quarantine Facility for Patients with COVID-19 with Mild Symptoms in Korea: Experience from Eighteen Residential Treatment Centers

With the rapid spread of coronavirus disease 2019 (COVID-19), a particularly sharp increase in the number of confirmed cases in Daegu and Gyeongbuk regions at the end of February, Korea faced an unprecedented shortage of medical resources, including hospital beds. To cope with this shortage, the government introduced a severity scoring system for patients with COVID-19 and designed a new type of quarantine facility for treating and isolating patients with mild symptoms out of the hospital, namely, the Residential Treatment Center (RTC). A patient with mild symptoms was immediately isolated in the RTC and continuously monitored to detect changes in symptoms. If the symptoms aggravate, the patient was transferred to a hospital. RTCs were designed by creating a quarantine environment in existing lodging facilities capable of accommodating > 100 individuals. The facilities were entirely divided into a clean zone (working area) and contaminated zone (patient zone), separating the space, air, and movement routes, and the staff wore level D personal protective equipment (PPE) in the contaminated zone. The staffs consisted of medical personnel, police officers, soldiers, and operation personnel, and worked in two or three shifts per day. Their duty was mainly to monitor the health conditions of quarantined patients, provide accommodations, and regularly collect specimens to determine if they can be released. For the past two months, RTCs secured approximately 4,000 isolation rooms and treated approximately 3,000 patients with mild symptoms and operated stably without additional spread of the disease in and out of the centers. Based on these experience, we would like to suggest the utilization of RTCs as strategic quarantine facilities in pandemic situations.

Waning Antibody Responses in Asymptomatic and Symptomatic SARS-CoV-2 Infection

We investigated the kinetics of severe acute respiratory syndrome coronavirus 2 neutralizing antibodies in 7 asymptomatic persons and 11 patients with pneumonia. The geometric mean titer of neutralizing antibodies declined from 219.4 at 2 months to 143.7 at 5 months after infection, indicating a waning antibody response.

Occurrence and transmission potential of asymptomatic and presymptomatic SARS-CoV-2 infections: A living systematic review and meta-analysis

BACKGROUND

There is disagreement about the level of asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We conducted a living systematic review and meta-analysis to address three questions: (1) Amongst people who become infected with SARS-CoV-2, what proportion does not experience symptoms at all during their infection? (2) Amongst people with SARS-CoV-2 infection who are asymptomatic when diagnosed, what proportion will develop symptoms later? (3) What proportion of SARS-CoV-2 transmission is accounted for by people who are either asymptomatic throughout infection or presymptomatic?

METHODS AND FINDINGS

We searched PubMed, Embase, bioRxiv, and medRxiv using a database of SARS-CoV-2 literature that is updated daily, on 25 March 2020, 20 April 2020, and 10 June 2020. Studies of people with SARS-CoV-2 diagnosed by reverse transcriptase PCR (RT-PCR) that documented follow-up and symptom status at the beginning and end of follow-up or modelling studies were included. One reviewer extracted data and a second verified the extraction, with disagreement resolved by discussion or a third reviewer. Risk of bias in empirical studies was assessed with an adapted checklist for case series, and the relevance and credibility of modelling studies were assessed using a published checklist. We included a total of 94 studies. The overall estimate of the proportion of people who become infected with SARS-CoV-2 and remain asymptomatic throughout infection was 20% (95% confidence interval [CI] 17-25) with a prediction interval of 3%-67% in 79 studies that addressed this review question. There was some evidence that biases in the selection of participants influence the estimate. In seven studies of defined populations screened for SARS-CoV-2 and then followed, 31% (95% CI 26%-37%, prediction interval 24%-38%) remained asymptomatic. The proportion of people that is presymptomatic could not be summarised, owing to heterogeneity. The secondary attack rate was lower in contacts of people with asymptomatic infection than those with symptomatic infection (relative risk 0.35, 95% CI 0.10-1.27). Modelling studies fit to data found a higher proportion of all SARS-CoV-2 infections resulting from transmission from presymptomatic individuals than from asymptomatic individuals. Limitations of the review include that most included studies were not designed to estimate the proportion of asymptomatic SARS-CoV-2 infections and were at risk of selection biases; we did not consider the possible impact of false negative RT-PCR results, which would underestimate the proportion of asymptomatic infections; and the database does not include all sources.

CONCLUSIONS

The findings of this living systematic review suggest that most people who become infected with SARS-CoV-2 will not remain asymptomatic throughout the course of the infection. The contribution of presymptomatic and asymptomatic infections to overall SARS-CoV-2 transmission means that combination prevention measures, with enhanced hand hygiene, masks, testing tracing, and isolation strategies and social distancing, will continue to be needed.

Occurrence and transmission potential of asymptomatic and presymptomatic SARS-CoV-2 infections: A living systematic review and meta-analysis

BACKGROUND

There is disagreement about the level of asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We conducted a living systematic review and meta-analysis to address three questions: (1) Amongst people who become infected with SARS-CoV-2, what proportion does not experience symptoms at all during their infection? (2) Amongst people with SARS-CoV-2 infection who are asymptomatic when diagnosed, what proportion will develop symptoms later? (3) What proportion of SARS-CoV-2 transmission is accounted for by people who are either asymptomatic throughout infection or presymptomatic?

METHODS AND FINDINGS

We searched PubMed, Embase, bioRxiv, and medRxiv using a database of SARS-CoV-2 literature that is updated daily, on 25 March 2020, 20 April 2020, and 10 June 2020. Studies of people with SARS-CoV-2 diagnosed by reverse transcriptase PCR (RT-PCR) that documented follow-up and symptom status at the beginning and end of follow-up or modelling studies were included. One reviewer extracted data and a second verified the extraction, with disagreement resolved by discussion or a third reviewer. Risk of bias in empirical studies was assessed with an adapted checklist for case series, and the relevance and credibility of modelling studies were assessed using a published checklist. We included a total of 94 studies. The overall estimate of the proportion of people who become infected with SARS-CoV-2 and remain asymptomatic throughout infection was 20% (95% confidence interval [CI] 17-25) with a prediction interval of 3%-67% in 79 studies that addressed this review question. There was some evidence that biases in the selection of participants influence the estimate. In seven studies of defined populations screened for SARS-CoV-2 and then followed, 31% (95% CI 26%-37%, prediction interval 24%-38%) remained asymptomatic. The proportion of people that is presymptomatic could not be summarised, owing to heterogeneity. The secondary attack rate was lower in contacts of people with asymptomatic infection than those with symptomatic infection (relative risk 0.35, 95% CI 0.10-1.27). Modelling studies fit to data found a higher proportion of all SARS-CoV-2 infections resulting from transmission from presymptomatic individuals than from asymptomatic individuals. Limitations of the review include that most included studies were not designed to estimate the proportion of asymptomatic SARS-CoV-2 infections and were at risk of selection biases; we did not consider the possible impact of false negative RT-PCR results, which would underestimate the proportion of asymptomatic infections; and the database does not include all sources.

CONCLUSIONS

The findings of this living systematic review suggest that most people who become infected with SARS-CoV-2 will not remain asymptomatic throughout the course of the infection. The contribution of presymptomatic and asymptomatic infections to overall SARS-CoV-2 transmission means that combination prevention measures, with enhanced hand hygiene, masks, testing tracing, and isolation strategies and social distancing, will continue to be needed.

Clinical Characteristics of COVID-19: Clinical Dynamics of Mild Severe Acute Respiratory Syndrome Coronavirus 2 Infection Detected by Early Active Surveillance

BACKGROUND

There is limited information describing the presenting characteristics and dynamic clinical changes in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection diagnosed in the early phase of illness. This study is a case series of patients with coronavirus disease 2019 (COVID-19) admitted to 11 hospitals in Korea.

METHODS

Patients with confirmed SARS-CoV-2 infection by positive polymerase chain reaction (PCR) testing of respiratory specimens by active surveillance that were finally discharged between February 20 and April 30, 2020 were included. Patients were classified into mild and non-mild groups on initial admission according to oxygen demand and Sequential Organ Failure Assessment score, and the mild group was followed up and subgrouped into non-aggravation and aggravation groups.

RESULTS

A total of 161 patients with SARS-CoV2 infection were enrolled. Among the mild group of 136 patients, 11.7% of patients experienced clinical aggravation during hospitalization, but there was no initial clinical parameter on admission predicting their aggravation. Fever (odds ratio [OR], 4.56), thrombocytopenia (OR, 12.87), fever (OR, 27.22) and lactate dehydrogenase (LDH) > 300 U/L (OR, 18.35), and CRP > 1 mg/dL (OR, 11.31) significantly indicated aggravation in the 1st, 2nd, 3rd, and 4th 5-day periods, respectively. PCR positivity lasted for a median of 22 days and 32 days after the onset of illness in the non-aggravation and aggravation groups, respectively.

CONCLUSION

Old age was associated with early severe presentation. Clinical aggravation among asymptomatic or mild patients could not be predicted initially but was heralded by fever and several laboratory markers during the clinical course.

Consensus statement on coronary intervention during the coronavirus disease 19 pandemic: from the Korean Society of Interventional Cardiology

Coronavirus disease 2019 (COVID-19) is a highly contagious disease caused by the novel virus severe acute respiratory syndrome coronavirus 2. The first case developed in December, 2019 in Wuhan, China; several months later, COVID-19 has become pandemic, and there is no end in sight. This disaster is also causing serious health problems in the area of cardiovascular intervention. In response, the Korean Society of Interventional Cardiology formed a COVID-19 task force to develop practice guidelines. This special article introduces clinical practice guidelines to prevent secondary transmission of COVID-19 within facilities; the guidelines were developed to protect patients and healthcare workers from this highly contagious virus. We hope these guidelines help healthcare workers and cardiovascular disease patients around the world cope with the COVID-19 pandemic.

Antibody Responses to SARS-CoV-2 at 8 Weeks Postinfection in Asymptomatic Patients

We compared levels of severe acute respiratory syndrome coronavirus 2 neutralizing antibodies in recovery plasma from 7 completely asymptomatic coronavirus disease patients with those in symptomatic patients in South Korea. We found that serologic diagnostic testing was positive for 71% (5/7) of completely asymptomatic patients, but neutralizing antibody response occurred in all 7 patients.

Consensus Statement on Coronary Intervention during the Coronavirus Disease 2019 (COVID-19) Pandemic: from the Korean Society of Interventional Cardiology (KSIC)

Coronavirus disease 2019 (COVID-19) is a highly contagious disease caused by the novel virus severe acute respiratory syndrome coronavirus-2. The first case developed in December, 2019 in Wuhan, China; several months later, COVID-19 has become pandemic, and there is no end in sight. This disaster is also causing serious health problems in the area of cardiovascular intervention. In response, the Korean Society of Interventional Cardiology formed a COVID-19 task force to develop practice guidelines. This special article introduces clinical practice guidelines to prevent secondary transmission of COVID-19 within facilities; the guidelines were developed to protect patients and healthcare workers from this highly contagious virus. We hope these guidelines help healthcare workers and cardiovascular disease patients around the world cope with the COVID-19 pandemic.