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HOME > Osong Public Health Res Perspect > Volume 14(1); 2023 > Article
Brief Report
Early countermeasures to COVID-19 at long-term care facilities in Gwangju Metropolitan City, Republic of Korea
Hye-Jin Kim1orcid, Jieun Kim1orcid, Yoon Suk Jang1orcid, Hanul Park1orcid, Jong Mu Kim1orcid, Young Joon Park1orcid, So-Yeon Ryu2orcid, Jun Hwi Cho2orcid, So Yeong Park2orcid, Sang-Eun Lee1orcid
Osong Public Health and Research Perspectives 2023;14(1):59-65.
DOI: https://doi.org/10.24171/j.phrp.2022.0293
Published online: February 1, 2023

1COVID-19 National Emergency Response, Central Disease Control Headquarters, Korea Disease Control and Prevention Agency, Cheongju, Korea

2Gwangju Center for Infectious Disease Control and Prevention, Gwangju, Korea

Corresponding author: Sang-Eun Lee COVID-19 National Emergency Response, Central Disease Control Headquarters, Korea Disease Control and Prevention Agency, 187 Osongsaengmyeong 2-ro, Osong-eup, Heungdeok-gu, Cheongju 28159, Korea E-mail: ondalgl@korea.kr
• Received: November 7, 2022   • Revised: December 25, 2022   • Accepted: December 27, 2022

© 2023 Korea Disease Control and Prevention Agency.

This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

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  • Objectives
    The coronavirus disease 2019 (COVID-19) pandemic has continued since its first detection in the Republic of Korea on January 20, 2020. This study describes the early countermeasures used to minimize the risk of COVID-19 outbreaks during cohort quarantine and compares the epidemiological characteristics of 2 outbreaks in long-term care facilities (LTCFs) in Gwangju Metropolitan City in summer 2020.
  • Methods
    An epidemiological investigation was conducted via direct visits. We investigated epidemiological characteristics, including incidence, morbidity, and mortality rates, for all residents and staff members. Demographic characteristics were analyzed using a statistical program. Additionally, the method of managing infection in LTCFs is described.
  • Results
    Residents and caregivers had high incidence rates in LTCF-A and LTCF-B, respectively. LTCF-B had a longer quarantine period than LTCF-A. The attack rate was 20.02% in LTCF-A and 27.9% in LTCF-B. The mortality rate was 2.3% (1/43) in LTCF-B, the only facility in which a COVID-19 death occurred.
  • Conclusion
    Extensive management requires contact minimization, which involves testing all contacts to mitigate further transmission in the early stages of LTCF outbreaks. The findings of this study can help inform and prepare public health authorities for COVID-19 outbreaks, particularly for early control in vulnerable facilities.
Since the first case of coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was confirmed in the Republic of Korea (ROK) on January 20, 2020, the disease has been identified in diverse sites in cluster patterns. Moreover, SARS-CoV-2 infection can manifest as a respiratory disease with severe pneumonia-like symptoms that require critical care [1]. The elderly population is generally susceptible, with a high incidence of severe disease and mortality. Those who attend gatherings face a high risk of infection and risk of complications. Deaths related to COVID-19 have been reported in other countries [24]. Eighty percent of deaths associated with COVID-19 were among adults aged ≥65 years, with the highest percentage of severe outcomes among persons aged ≥85 years [5]. Mortality was reported most commonly among individuals aged ≥80 years [6].
According to the Korea Disease Control and Prevention Agency (KDCA), as of July 1, 2020, deaths in the ROK due to COVID-19 totaled 282 cases of 1,285,231 individuals tested, with a mortality rate of 2.1%. The total number of cases in Gwangju Metropolitan City was 56 [7]. COVID-19 outbreaks have resulted from a variety of gatherings, including in churches and temples. The first long-term care facility (LTCF) outbreak and resident death occurred in Gwangju Metropolitan City. There have been no prior reports on early countermeasures for cluster LTCF outbreaks. This study describes the epidemiological characteristics and efforts to mitigate the spread of COVID-19 in LTCFs. It compares 2 LTCFs’ extensive public health responses to COVID-19 outbreaks in order to assess similarities and differences in disease spread and individuals affected.
Epidemiological Investigation
Based on the Infectious Disease Control and Prevention Act, we identified and investigated patients as relevant who had worked at and been infected at LTCF-A and LTCF-B, and their contacts between June 26, 2020 and July 30, 2020 [8]. A confirmed person was defined as someone with laboratory-confirmed COVID-19 infection, regardless of clinical signs and symptoms [9,10], and the index case was defined as the first confirmed case of SARS-CoV-2 infection within a cluster outbreak. After epidemiological investigation to confirm the route of transmission, origin, and exposure environment, patients with COVID-19 were given appropriate medical care. We obtained information on demographic characteristics from interviews using standardized epidemiological investigation forms. For supplemental measures to trace contacts, we obtained additional personal epidemiological information using the global positioning system (GPS), credit card transactions, drug utilization review, and closed-circuit television.
Outbreak Recognition and Response Measures
We were alerted to the index cases of COVID-19 as caregivers who worked in LTCF-A and LTCF-B. The first confirmed case included another cluster associated with suspected acute respiratory illness.
The KDCA’s immediate response team was sent to the spot for epidemiological investigation with contact tracing. Countermeasure response teams were launched immediately, namely the Gwangju Center for Infectious Disease Control and Prevention, Gwangju Infectious Disease Response Team, and Gwangju Buk-gu Public Health Center. The investigative response identified an outbreak during the cohort isolation group’s quarantine period in LTCF-A and LTCF-B in Gwangju Metropolitan City, during a COVID-19 mass screening of residents (n=52) and staff members (n=31).
After the index case was identified, movement within LTCF-A and LTCF-B was limited. Visitors were prohibited from entering the facilities in order to limit exposure, since interaction had the potential for disease transmission. Each resident was assigned to a single room or a room with divided partitions, and no group activities were allowed. To prevent additional transmission, personal protective equipment (PPE) for staff members was always worn when caring for residents. Fever and symptoms such as cough, myalgia, and headaches were monitored and recorded daily. Nasopharyngeal swab specimens from all residents and staff, including caregivers, were screened using real-time reverse-transcription polymerase chain reaction (RT-PCR). All residents and staff were isolated for testing every 3 days and quarantined for 14 days after a positive result was confirmed. Those who were confirmed positive were transferred to other hospitals or treatment centers in the community. A person who had a negative test result after contact with a confirmed case was mandated to remain quarantined at the facility for 14 days.
Enhanced hygiene measures were implemented, including disinfection of surfaces and periodic natural ventilation through windows. In addition, after the contaminated room or area was cleaned, environmental sampling was performed. Environmental testing for SARS-CoV-2 at LTCF-A and LTCF-B was performed on July 1, 2020 and July 9, 2020, respectively.
Ethics Statement
Ethics approval was waived for this study because it was considered part of a response to a public health crisis.
LTCF-A is a 2-story structure located near a residential area. Twenty-six residents were managed by 14 staff members between June 26, 2020 and July 30, 2020. Resident space was located on the first and second floors of the building. The space was utilized by placing 2 persons per room. An elevator was used to move food and supplies, but not people, between floors. Ventilation was possible only by opening the window.
LTCF-B is a 4-story structure located in a rural area. Twenty-six residents were managed by 17 staff members. The space was utilized by placing 2 to 4 persons per room. Resident space was located on the first and second floors, and staff space was located on the third floor and the first basement floor of the building. Air conditioning and open windows were used for ventilation.
LTCF-A was quarantined immediately on July 1, 2020, after a caregiver on staff was identified on June 30 as the index case, and RT-PCR testing was performed on all personnel. As a result, 3 residents were confirmed to be positive and were transferred immediately to a hospital. As a complementary measure, all remaining personnel were quarantined for cohort isolation. On July 3, 3 asymptomatic residents were confirmed positive, after which no further positive results occurred until July 17, due to the 14-day quarantine.
Among the 26 residents of LTCF-A, all 6 positive cases were >70 years old (mean age, 81.5), and the 2 positive staff had a mean age of 43.5 years (Table 1). In LTCF-B, the average age of positive cases among residents was 87.6 years, and among staff was 56.4 years. More than 80% of the positive staff members showed initial symptoms such as fever, muscle pain, and fatigue. However, 100% (6/6) of the residents in LTCF-A and 71.4% (5/7) in LTCF-B were asymptomatic. Only 28.6% (2/7) of residents in LTCF-B showed symptoms, such as fever, muscle pain, sore throat, cough, and lethargy. Among the positive residents, 1 person died on July 16 from lethargy. The positive residents had comorbidities, including 11 with dementia (55%), 7 with hypertension (35%), 5 with diabetes (25%), and 3 with hyperlipidemia (n=3). Five residents were able to ambulate in a wheelchair, and 1 had difficulty in communication and movement (data not shown).
As illustrated in Figure 1, the index case at LTCF-B (symptomatic date: June 29), confirmed subsequently as positive for SARS-CoV-2, was already a patient under investigation on July 1. The index case at LTCF-B met the index case of LTCF-A on June 27 based on GPS tracking (data not shown). All LTCF-B personnel were evaluated and tested using RT-PCR as well. As a result of cumulative testing, on July 2, 2020, 4 people were confirmed positive for SARS-CoV-2, and the remaining personnel were isolated in single rooms on the second and third floors as a follow-up measure. Two people tested positive on July 5, 8, and July 10.
Cohort isolation was sustained for 14 days after the last confirmed case. After the start of quarantine on July 1 in LTCF-B, staff in the basement oversaw floor 1 residents, and staff on floor 3 oversaw floor 2 residents.
To prevent infection, staff members were required to wear protective suits when entering the room. Movement between floors outside of each person's living area was prohibited for disease control. The secondary attack rate was 8.3% (1/12), as close contacts with the first index case mingled among household members associated with LTCF-A.
For environmental evaluation, on July 1, LTCF-A collected 31 samples from patients’ contact places (door handles, toilet handles, toilet bowls, etc.). As indicated by RT-PCR, only the handle of the front door was confirmed to be positive for SARS-CoV-2. The exposure site was sterilized 1 hour before sampling; however, the entrance door handle was not sterilized because the front door was open. Cycle threshold values for the E gene and RdRp gene of the door handle were 33.25 and 35.07, respectively. On July 9, 25 samples were collected from major contact places, including air purifiers and ventilation systems in LTCF-B. All of these RT-PCR test results were negative.
As a result of the epidemiological investigation associated with contact tracing, the expected transmission is shown in Figure 2. The first transmission was initiated by a meeting between the index cases of LTCF-A and LTCF-B. Transmission within LTCF-A was caused by only 1 staff member, transmission in LTCF-B started from the staff of LTCF-A, and additional transmission was caused by each facility’s workers.
This report has shown that countermeasures to COVID-19 outbreaks among the elderly who have greater risk of developing a more severe form of the disease. Strategy measures for COVID-19 among the elderly were followed by comprehensive tracing of all identified contacts. The extensive public health response to support LTCF residents included active testing to ascertain a mass screening for case detection and mitigate the risk of SARS-CoV-2 infection, quarantine of all contacts, and treatment of confirmed cases.
A previous study indicated that most elderly people residing in LTCFs have a significantly higher risk of severe disease and death [11]. Numerous deaths due to SARS-CoV-2 in LTCFs have been reported in other countries [1214]. Previous studies have reported that most facilities requiring nursing had a significantly higher risk of severe disease and death, and it was estimated that approximately 42% of deaths were associated with COVID-19 [12]. In this study, the mortality rate was 8.33% (1/12) in LTCF-B. We found that the mortality rate was lower than previous findings, which ranged between 20.8% and 28.0% in similar populations [15,16]. This result indicates that the attack rate (incidence rate) was 20.02% and 27.9% in LTCF-A and LTCF-B, respectively. The morbidity rates were 5.0% (2/40) in LTCF-A and 14.0% (6/43) in LTCF-B. The mortality rate may be higher among those with pre-existing comorbidities, particularly cardiovascular disease, diabetes, chronic respiratory disease, hypertension, and cancer [17].
This study showed a high prevalence of asymptomatic infections among infected older residents, and of those who tested positive, only staff members exhibited symptoms. Viral shedding may peak in the pre-symptomatic phase within the primary stage of infection [18]. Most residents had a high risk due to the presence of multiple comorbidities, such as diabetes, high blood pressure, and dementia. Almost all the residents who tested positive had underlying chronic medical conditions. Among the positive residents in both facilities, all from LTCF-A and 71.4% from LTCF-B had dementia, which was in accordance with the asymptomatic state. Furthermore, none of the staff members of LTCF-A and 20% of those in LTCF-B were asymptomatic.
This result differs from a report wherein 75% of nursing home staff were asymptomatic [19]. The quarantine periods were 20 days for LTCF-A and 32 days for LTCF-B. The countermeasures were the same; however, the quarantine periods were different. It is estimated that the asymptomatic rate among caregivers is high. Contagious symptomatic or asymptomatic carriers of SAR-CoV-2 could represent the leading cause of increased COVID-19 transmission [20].
Social gatherings may pose an increased risk of infection. Residents and workers share space and materials in nursing facilities. Residents had a high incidence rate in LTCF-A while caregivers had a higher incidence rate in LTCF-B. The total quarantine period was extended (17 days at LTCF-A and 29 days at LTCF-B) after confirming the last positive case. There was no additional transmission by positive residents in LTCF-A, whereas more transmission occurred among caregivers in LTCF-B. Physical interactions with personnel may result in an increase in infectious diseases [21]. Therefore, staff must be educated to mitigate transmission during the quarantine period.
There were concerns about worsening of symptoms due to inherent characteristics of the elderly, such as the presence of underlying diseases like dementia, that required management. More effort was required to mitigate the risk of SARS-CoV-2 infection among these vulnerable groups. Therefore, RT-PCR diagnostic testing was conducted every 3 days as a countermeasure for the possibility of worsening asymptomatic cases. This method focused on rapidly identifying and relocating confirmed cases from the cohort environment to decrease the frequency of SARS-CoV-2 infection in the facility. To reduce contact and exposure, each resident was assigned to a single or double room. It has been reported that the incidence and mortality doubled as density increased [22]. Team-based approaches, such as space separation, routine symptom monitoring of staff and residents, allocation of sufficient PPE, community support, and testing capacity, have been implemented to reduce additional infections. Similarly, other reports have shown reductions in incidence and mortality through preventive isolation (self-confinement) [23,24].
The current study has some limitations. Analysis of exposure risk was not possible because research, such as surveys on individual behavioral characteristics, could not be conducted. Although it is a report on the early countermeasures of an LTCF group outbreak in the early stages of the COVID-19 pandemic, the findings of this study can help inform and prepare public health authorities for COVID-19 outbreaks or other infectious disease outbreaks, particularly in setting up quarantine in vulnerable facilities. We hope that our records can be effectively utilized to mitigate SARS-CoV-2 transmission and protect vulnerable populations in LTCFs.

Ethics Approval

Ethics approval was waived for this study because it was considered part of a response to a public health crisis.

Conflicts of Interest

The authors have no conflicts of interest to declare.

Funding

This work was supported by funding from the Korea Disease Control and Prevention Agency (2020, 6231-335-210-01).

Availability of Data

All data generated or analyzed during this study are included in this published article. Other data may be requested through the corresponding author.

Authors’ Contributions

Investigation: HJK, JK, YSJ, HP, JMK, SYR, JHC, SYP; Project administration: YJP; Supervision: SEL; Writing–original draft: HJK; Writing–review & editing: all authors. All authors read and approved the final manuscript.

Figure 1.
Epidemic curve of coronavirus disease 2019 outbreaks in long-term care facilities (LCTFs) by date of symptom onset. (A) LTCF-A, (B) LTCF-B.
j-phrp-2022-0293f1.jpg
Figure 2.
Identification of transmission route according to contact tracing in long-term care facilities (LCTFs). (A) LTCF-A, (B) LTCF-B.
j-phrp-2022-0293f2.jpg
j-phrp-2022-0293f3.jpg
Table 1.
Demographic characteristics of COVID-19 patients at facilities A and B
Characteristic Overall Facility A
Facility B
Total Resident Worker Total Resident Worker
Total 40 26 14 43 26 17
 Mean age (y) 74.4 87.1 50.9 72.3 87.2 49.5
 Sex
  Male 5 2 1 1 3 1 2
  Female 78 38 25 13 40 25 15
Confirmed cases 20 8 6 2 12 7 5
 Mean age (y) 72.0 81.5 43.5 74.6 87.6 56.4
 Sex
  Male 1 1 1 0 0 0 0
  Female 19 7 5 2 12 7 5
 Symptoms before diagnosis
  Symptomatic 8 2 0 2 6 2 4
  Asymptomatic 12 6 6 0 6 5 1
 Sign
  Fever 5 1 0 1 4 1 3
  Headache 1 1 0 1 0 0 0
  Muscle pain, fatigue 2 1 0 1 1 0 1
  Sore throat, cough 2 0 0 0 2 0 2
  Lethargy 1 0 0 0 1 1 0
 Underlying disease
  Dementia 11 6 6 0 5 5 0
  Hypertension 7 3 3 0 4 4 0
  Diabetes 5 1 1 0 4 3 1
  Hyperlipidemia 3 0 0 0 3 1 2
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