Community-Acquired Pneumococcal Pneumonia in Highly Vaccinated Population: Analysis by Serotypes, Vaccination Status, and Underlying Medical Conditions

Background@#Targeted risk population has been highly vaccinated against pneumococcal diseases in South Korea. Despite this, the pneumococcal serotype distribution is evolving, which impedes efficient roll-out of vaccines. @*Methods@#This prospective cohort study included patients aged ≥ 19 years with communityacquired pneumonia (CAP) from five university hospitals in South Korea between September 2018 and July 2021. The outcomes of interest were the demographic and clinical characteristics of patients with CAP, pneumococcal serotype distribution, and risk factors of 30-day mortality in patients with pneumococcal CAP (pCAP). Considering the high seroprevalence, we analyzed the clinical characteristics of serotype 3 pCAP. @*Results@#A total of 5,009 patients hospitalized with CAP was included (mean age ± standard deviation, 70.3 ± 16.0 years; 3,159 [63.1%] men). Streptococcus pneumoniae was the leading causative agent of CAP (11.8% overall, 17.7% in individuals aged < 65 years with chronic medical conditions). Among the 280 serotyped Streptococcus pneumococcus, serotype 3 was the most common (10.0%), followed by serotypes 19A (8.9%), 34 (8.9%), and 35B (8.9%).Non-vaccine serotypes (serotype 35B [13.9%] and 34 [12.0%]) were the most prevalent in 108 individuals vaccinated with 23-valent pneumococcal polysaccharide vaccine (PPSV23).Serotype 3 was prevalent, irrespective of PPSV23 vaccination status, and more common in individuals with chronic lung disease (P = 0.008). Advanced age (adjusted odds ratio [aOR], 1.040; 95% confidence interval [CI], 1.011–1.071), long-term care facility residence (aOR, 2.161; 95% CI, 1.071–4.357), and bacteremia (aOR, 4.193; 95% CI, 1.604–10.962) were independent risk factors for 30-day mortality in patients with pCAP. PPSV23 vaccination reduced the risk of mortality (aOR, 0.507; 95% CI, 0.267–0.961). @*Conclusion@#Serotype 3 and 19A were still the most common serotypes of pCAP in South Korea despite the national immunization program of 13-valent pneumococcal conjugated vaccine in children and PPSV23 in old adults. PPSV23 vaccination might reduce the risk of mortality in patients with pCAP.

Concurrent Subacute Thyroiditis and Graves’ Disease After COVID-19:A Case Report

There are many reports of subacute thyroiditis (SAT) that occurred after the coronavirus disease 2019 (COVID-19), but no such case has been reported in Korea. Moreover, the simultaneous occurrence of SAT and Graves’ disease (GD) is rare. Here, we describe a patient who developed SAT and GD after the second episode of COVID-19. A 27-year-old woman with no known history of thyroid disease presented with fever, upper respiratory tract symptoms, and painful neck swelling. Thyroid function tests revealed thyrotoxicosis, and thyroid ultrasound showed heterogeneous echogenicity of enlarged thyroid glands. Her initial clinical presentation was consistent with SAT after viral infection, with typical neck tenderness and spontaneous improvement of thyrotoxicosis without antithyroid drug use. However, this case had some atypical features, such as an elevated thyroid-stimulating immunoglobulin level, relapse of thyrotoxicosis in short-term follow-up, and increased Tc-99m pertechnetate uptake, suggesting the coexistence of GD. About two months after methimazole (15 mg/day) was prescribed, she was lost to follow up again. We report the first case of unusual co-occurrence of SAT and GD following COVID-19.

Vaccination Rates of Hospitalized Patients at High Risk of Severe COVID-19: A Single-Center CrossSectional Study / 감염과화학요법

We investigated coronavirus disease 2019 (COVID-19) vaccination rate in patients admitted to chronic pulmonary disease, cardiovascular disease, chronic kidney disease, and cancer wards in the third week of April 2022 to determine the immunity level of these vulnerable groups. Compared to the general population, our study subjects had lower vaccination rates, except for higher percentages of boosted individuals in patients with chronic pulmonary disease and cardiovascular disease. This tendency was most pronounced in cancer patients, less than half of whom were boosted. Patients with cancer should be encouraged to complete their COVID-19 vaccination.

The Incidence and Risk Factors of Renal Insufficiency among Korean HIV infected Patients: The Korea HIV/AIDS Cohort Study / 감염과화학요법

Renal insufficiency is one of the common issues in people living with human immunodeficiency virus (PLHIV). We studied the incidence and risk factors for renal insufficiency in male PLHIV using the Korea HIV/acquired immunodeficiency syndrome (AIDS) Cohort Study. Among the 830 enrolled patients, 32 (3.9%) cases of renal insufficiency occurred over 9576 patient-years of follow-up. The incidence of renal insufficiency in HIVinfected men in this study was 3.3 per 1000 patient-years. Diabetes mellitus, dyslipidemia, tenofovir or non-nucleoside reverse transcriptase inhibitor exposure for >1 year, and AIDSdefining illness were risk factors for renal insufficiency.

Immunogenicity and Reactogenicity of Ad26.COV2.S in Korean Adults: A Prospective Cohort Study

Background@#As the coronavirus disease 2019 (COVID-19) pandemic continues, there are concerns regarding waning immunity and the emergence of viral variants. The immunogenicity of Ad26.COV2.S against wild-type (WT) and variants of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) needs to be evaluated.Method: This prospective cohort study was conducted between June 2021 and January 2022 at two university hospitals in South Korea. Healthy adults who were scheduled to be vaccinated with Ad26.COV2.S were enrolled in this study. The main outcomes included anti-spike (S) IgG antibody and neutralizing antibody responses, S-specific T-cell responses (interferon-γ enzyme-linked immunospot assay), solicited adverse events (AEs), and serious AEs. @*Results@#Fifty participants aged ≥ 19 years were included in the study. Geometric mean titers (GMTs) of anti-S IgG were 0.4 U/mL at baseline, 5.2 ± 3.0 U/mL at 3–4 weeks, 55.7 ± 2.4 U/mL at 5–8 weeks, and 81.3 ± 2.5 U/mL at 10–12 weeks after vaccination. GMTs of 50% neutralizing dilution (ND50) against WT SARS-CoV-2 were 164.6 ± 4.6 at 3-4 weeks, 313.9 ± 3.6 at 5–8 weeks, and 124.4 ± 2.6 at 10–12 weeks after vaccination. As for the S-specific T-cell responses, the median number of spot-forming units/10 6 peripheral blood mononuclear cell was 25.0 (5.0–29.2) at baseline, 60.0 (23.3–178.3) at 5-8 weeks, and 35.0 (13.3–71.7) at 10–12 weeks after vaccination. Compared to WT SARS-CoV-2, ND50 against Delta and Omicron variants was attenuated by 3.6-fold and 8.2-fold, respectively. The most frequent AE was injection site pain (82%), followed by myalgia (80%), fatigue (70%), and fever (50%). Most AEs were grade 1–2, and resolved within two days. @*Conclusion@#Single-dose Ad26.COV2.S was safe and immunogenic. NAb titer and S-specific T-cell immunity peak at 5–8 weeks and rather decrease at 10–12 weeks after vaccination.Cross-reactive neutralizing activity against the Omicron variant was negligible.

How lessons learned from the 2015 Middle East respiratory syndrome outbreak affected the response to coronavirus disease 2019 in the Republic of Korea

The Republic of Korea (ROK) experienced a public health crisis due to Middle East respiratory syndrome (MERS) in 2015 and is currently going through the coronavirus disease 2019 (COVID-19) pandemic. Lessons learned from the disastrous MERS outbreak were ref lected in the preparedness system, and the readiness capabilities that were subsequently developed enabled the country to successfully flatten the epidemic curve of COVID-19 in late February and March 2020. In this review, we summarize and compare the epidemiology and response of the ROK to the 2015 MERS outbreak and the COVID-19 epidemic in early 2020. We emphasize that, because further COVID-19 waves seem inevitable, it is urgent to develop comprehensive preparedness and response plans for the worst-case scenarios of the COVID-19 pandemic. Simultaneously strengthening healthcare capacity to endure the peak demand and implementing smart strategies to sustain social distancing and public hygiene are necessary until safe and effective therapeutics and vaccines against COVID-19 are available.

Developing a Framework for Pandemic COVID-19 Vaccine Allocation: a Modified Delphi Consensus Study in Korea

Background@#This study presents a framework for determining the allocation and distribution of the limited amount of vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). @*Methods@#After analyzing the pandemic strategies of the major organizations and countries and with a literature review conducted by a core panel, a modified Delphi survey was administered to 13 experts in the fields of vaccination, infectious disease, and public health in the Republic of Korea. The following topics were discussed: 1) identifying the objectives of the vaccination strategy, 2) identifying allocation criteria, and 3) establishing a step-bystep vaccination framework and prioritization strategy based on the allocation criteria. Two rounds of surveys were conducted for each topic, with a structured questionnaire provided via e-mail in the first round. After analyzing the responses, a meeting with the experts was held to obtain consensus on how to prioritize the population groups. @*Results@#The first objective of the vaccination strategy was maintenance of the integrity of the healthcare system and critical infrastructure, followed by reduction of morbidity and mortality and reduction of community transmission. In the initial phase, older adult residents in care homes, high-risk health and social care workers, and personal support workers who work in direct contact with coronavirus disease 2019 (COVID-19) patients would be prioritized. Expansion of vaccine supply would allow immunization of older adults not included in phase 1, followed by healthcare workers not previously included and individuals with comorbidities. Further widespread vaccine supply would ensure availability to the extended adult age groups (50–64 years old), critical workers outside the health sector, residents who cannot socially distance, and, eventually, the remaining populations. @*Conclusion@#This survey provides the much needed insight into the decision-making process for vaccine allocation at the national level. However, flexibility in adapting to strategies will be essential, as new information is constantly emerging.

Polyarthralgia and Myalgia Syndrome after ChAdOx1 nCOV-19 Vaccination

Since February 26, 2021, when vaccination against coronavirus disease 2019 (COVID-19) began in South Korea, patients who visited the Korea University Guro Hospital with suspected adverse events after COVID-19 vaccination were monitored actively with interest. We encountered five unusual cases of polyarthralgia and myalgia syndrome in patients who received the ChAdOx1 nCOV-19 (AstraZeneca) vaccine. The patients (median age 67 years) were not previously diagnosed with arthropathy and rheumatologic diseases. They developed fever, myalgia, joint pain, and swelling three to seven days after vaccination. The symptoms persisted for up to 47 days despite antipyretic treatment. Arthralgia occurred in multiple joints, including small and large joints. A whole-body Technetium-99m methylene diphosphonate bone scan revealed unusual uptakes in the affected joints. Non-steroidal anti-inflammatory drugs with or without prednisolone relieved the symptoms of all patients. Further monitoring is required to clarify the long-term prognosis of this syndrome.

Early Safety Monitoring of COVID-19 Vaccines in Healthcare Workers

Hospital-based surveillance for adverse events was conducted on healthcare workers after they received the first dose of coronavirus disease 2019 (COVID-19) vaccine. Among the two new platform vaccines (messenger RNA- and adenoviral vector-based vaccines), the rates of systemic adverse events were significantly higher among adenovirus-vectored vaccine recipients. Fatigue (87.6% vs. 53.8%), myalgia (80.8% vs. 50.0%), headache (72.0% vs.28.8%), and fever (≥ 38.0°C, 38.7% vs. 0%) were the most common adverse events among adenovirus-vectored vaccine recipients, but most symptoms resolved within 2 days. Both types of COVID-19 vaccines were generally safe, and serious adverse events rarely occurred.

Developing a Framework for Pandemic COVID-19 Vaccine Allocation: a Modified Delphi Consensus Study in Korea

Background@#This study presents a framework for determining the allocation and distribution of the limited amount of vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). @*Methods@#After analyzing the pandemic strategies of the major organizations and countries and with a literature review conducted by a core panel, a modified Delphi survey was administered to 13 experts in the fields of vaccination, infectious disease, and public health in the Republic of Korea. The following topics were discussed: 1) identifying the objectives of the vaccination strategy, 2) identifying allocation criteria, and 3) establishing a step-bystep vaccination framework and prioritization strategy based on the allocation criteria. Two rounds of surveys were conducted for each topic, with a structured questionnaire provided via e-mail in the first round. After analyzing the responses, a meeting with the experts was held to obtain consensus on how to prioritize the population groups. @*Results@#The first objective of the vaccination strategy was maintenance of the integrity of the healthcare system and critical infrastructure, followed by reduction of morbidity and mortality and reduction of community transmission. In the initial phase, older adult residents in care homes, high-risk health and social care workers, and personal support workers who work in direct contact with coronavirus disease 2019 (COVID-19) patients would be prioritized. Expansion of vaccine supply would allow immunization of older adults not included in phase 1, followed by healthcare workers not previously included and individuals with comorbidities. Further widespread vaccine supply would ensure availability to the extended adult age groups (50–64 years old), critical workers outside the health sector, residents who cannot socially distance, and, eventually, the remaining populations. @*Conclusion@#This survey provides the much needed insight into the decision-making process for vaccine allocation at the national level. However, flexibility in adapting to strategies will be essential, as new information is constantly emerging.

Polyarthralgia and Myalgia Syndrome after ChAdOx1 nCOV-19 Vaccination

Since February 26, 2021, when vaccination against coronavirus disease 2019 (COVID-19) began in South Korea, patients who visited the Korea University Guro Hospital with suspected adverse events after COVID-19 vaccination were monitored actively with interest. We encountered five unusual cases of polyarthralgia and myalgia syndrome in patients who received the ChAdOx1 nCOV-19 (AstraZeneca) vaccine. The patients (median age 67 years) were not previously diagnosed with arthropathy and rheumatologic diseases. They developed fever, myalgia, joint pain, and swelling three to seven days after vaccination. The symptoms persisted for up to 47 days despite antipyretic treatment. Arthralgia occurred in multiple joints, including small and large joints. A whole-body Technetium-99m methylene diphosphonate bone scan revealed unusual uptakes in the affected joints. Non-steroidal anti-inflammatory drugs with or without prednisolone relieved the symptoms of all patients. Further monitoring is required to clarify the long-term prognosis of this syndrome.

Early Safety Monitoring of COVID-19 Vaccines in Healthcare Workers

Hospital-based surveillance for adverse events was conducted on healthcare workers after they received the first dose of coronavirus disease 2019 (COVID-19) vaccine. Among the two new platform vaccines (messenger RNA- and adenoviral vector-based vaccines), the rates of systemic adverse events were significantly higher among adenovirus-vectored vaccine recipients. Fatigue (87.6% vs. 53.8%), myalgia (80.8% vs. 50.0%), headache (72.0% vs.28.8%), and fever (≥ 38.0°C, 38.7% vs. 0%) were the most common adverse events among adenovirus-vectored vaccine recipients, but most symptoms resolved within 2 days. Both types of COVID-19 vaccines were generally safe, and serious adverse events rarely occurred.

The Practice Guideline for Vaccinating Korean Patients With Autoimmune Inflammatory Rheumatic Disease

To develop a clinical practice guideline for vaccination in patients with autoimmune inflammatory rheumatic disease (AIIRD), the Korean College of Rheumatology and the Korean Society of Infectious Diseases developed a clinical practice guideline according to the clinical practice guideline development manual. Since vaccination is unlikely to cause AIIRD or worsen disease activities, required vaccinations are recommended. Once patients are diagnosed with AIIRD, treatment strategies should be established and, at the same time, monitor their vaccination history. It is recommended to administer vaccines when the disease enters the stabilized stage. Administering live attenuated vaccines in patients with AIIRD who are taking immunosuppressants should be avoided. Vaccination should be considered in patients with AIIRD, prior to initiating immunosuppressants. It is recommended to administer influenza, Streptococcus pneumoniae, hepatitis A, hepatitis B, herpes zoster, measles-mumps-rubella virus, human papillomavirus, and tetanus-diphtheria-pertussis vaccines in patients with AIIRD; such patients who planned to travel are generally recommended to be vaccinated at the recommended vaccine level of healthy adults. Those who live in a household with patients with AIIRD and their caregivers should also be vaccinated at levels that are generally recommended for healthy adults.

Prospective cohort data quality assurance and quality control strategy and method: Korea HIV/AIDS Cohort Study / 한국역학회지

OBJECTIVES@#The aim of effective data quality control and management is to minimize the impact of errors on study results by identifying and correcting them. This study presents the results of a data quality control system for the Korea HIV/AIDS Cohort Study that took into account the characteristics of the data. @*METHODS@#The HIV/AIDS Cohort Study in Korea conducts repeated measurements every 6 months using an electronic survey administered to voluntarily consenting participants and collects data from 21 hospitals. In total, 5,795 sets of data from 1,442 participants were collected from the first investigation in 2006 to 2016. The data refining results of 2015 and 2019 were converted into the data refining rate and compared. @*RESULTS@#The quality control system involved 3 steps at different points in the process, and each step contributed to data quality management and results. By improving data quality control in the pre-phase and the data collection phase, the estimated error value in 2019 was 1,803, reflecting a 53.9% reduction from 2015. Due to improvements in the stage after data collection, the data refining rate was 92.7% in 2019, a 24.21%p increase from 2015. @*CONCLUSIONS@#Despite this quality management strategy, errors may still exist at each stage. Logically possible errors for the post-review refining of downloaded data should be actively identified with appropriate consideration of the purpose and epidemiological characteristics of the study data. To improve data quality and reliability, data management strategies should be systematically implemented.

Significance of Decreasing Rate of HIV and HBV Co-infection in a Nationwide Korean HIV/AIDS Cohort

From December 2006 to December 2016, 1093 human immunodeficiency virus (HIV) individuals < 70 years enrolled in Korea human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) cohort were analyzed to investigate the prevalence of HIV/HBV co-infection rate and hepatitis B virus surface antibody (HBsAb) positive rate based on birth year. The HBV co-infection prevalence rate was the highest (8.8%) in patients born between 1960 and 1964 and the lowest (0%) among those born between 1995 and 1999. A decreasing linear trend of HBV co-infection rate was observed according to the 5-year interval changes. HBsAb-positive rate was only 58.1% in our study. The national HBV vaccination programs have effectively lowered the HBV co-infection rate in HIV population. However, it is identified that the HIV population has low HBsAb positive rate. Further evidences supporting efficacy of booster immunization for HBsAb negative HIV patients are required and efforts should be made to increase HBsAb positive rates among HIV patients to prevent horizontal transmission.

A Debate on Public Health Responses to COVID-19: Focused Protection versus Sustained Suppression

With the coronavirus disease 2019 (COVID-19) pandemic persisting for a long time, there have been debates about the public health response strategies. We conducted a survey of adult infectious disease specialists on public health responses to COVID-19. Most responded that regulations on multi-use facilities should be maintained or strengthened, but schools should not be closed, except in cases where an outbreak occurs within the school. A slightly higher percentage of experts supported focused protection rather than sustained suppression. While the focused protection strategy might suffice in low-level epidemic situations, social distancing should be reinforced by shifting to a strategy closer to sustained suppression in the eventuality of rapid spread of outbreaks.

Prospective cohort data quality assurance and quality control strategy and method: Korea HIV/AIDS Cohort Study / 한국역학회지

OBJECTIVES@#The aim of effective data quality control and management is to minimize the impact of errors on study results by identifying and correcting them. This study presents the results of a data quality control system for the Korea HIV/AIDS Cohort Study that took into account the characteristics of the data. @*METHODS@#The HIV/AIDS Cohort Study in Korea conducts repeated measurements every 6 months using an electronic survey administered to voluntarily consenting participants and collects data from 21 hospitals. In total, 5,795 sets of data from 1,442 participants were collected from the first investigation in 2006 to 2016. The data refining results of 2015 and 2019 were converted into the data refining rate and compared. @*RESULTS@#The quality control system involved 3 steps at different points in the process, and each step contributed to data quality management and results. By improving data quality control in the pre-phase and the data collection phase, the estimated error value in 2019 was 1,803, reflecting a 53.9% reduction from 2015. Due to improvements in the stage after data collection, the data refining rate was 92.7% in 2019, a 24.21%p increase from 2015. @*CONCLUSIONS@#Despite this quality management strategy, errors may still exist at each stage. Logically possible errors for the post-review refining of downloaded data should be actively identified with appropriate consideration of the purpose and epidemiological characteristics of the study data. To improve data quality and reliability, data management strategies should be systematically implemented.

The Practice Guideline for Vaccinating Korean Patients with Autoimmune Inflammatory Rheumatic Disease / 감염과화학요법

To develop a clinical practice guideline for vaccination in patients with autoimmune inflammatory rheumatic disease (AIIRD), the Korean College of Rheumatology and theKorean Society of Infectious Diseases developed a clinical practice guideline according to the clinical practice guideline development manual. Since vaccination is unlikely to cause AIIRD or worsen disease activities, required vaccinations are recommended. Once patients are diagnosed with AIIRD, treatment strategies should be established and, at the same time, monitor their vaccination history. It is recommended to administer vaccines when the disease enters the stabilized stage. Administering live attenuated vaccines in patients with AIIRD who are taking immunosuppressants should be avoided. Vaccination should be considered in patients with AIIRD, prior to initiating immunosuppressants. It is recommended to administer influenza, Streptococcus pneumoniae, hepatitis A, hepatitis B, herpes zoster, measlesmumps- rubella virus, human papillomavirus, and tetanus-diphtheria-pertussis vaccines in patients with AIIRD; such patients who planned to travel are generally recommended to be vaccinated at the recommended vaccine level of healthy adults. Those who live in a household with patients with AIIRD and their caregivers should also be vaccinated at levels that are generally recommended for healthy adults.

Survival Trend of HIV/AIDS Patients Starting Antiretroviral Therapy in South Korea between 2001 and 2015

Purpose@#In the recent antiretroviral therapy (ART) era, a large proportion of Korean patients with human immunodeficiency virus (HIV) infection were shown to have low CD4 cell counts at diagnosis and during ART initiation. We investigated the survival trends in patients living with HIV/acquired immunodeficiency syndrome (AIDS) in Korea who started ART in the 2000s, and evaluated the risk factors for mortality to elucidate the association between survival and low CD4 cell counts at ART initiation. @*Materials and Methods@#Patients with HIV infection who were aged >18 years and had started ART between 2001 and 2015 in the Korean HIV/AIDS cohort study were enrolled. We compared the clinical characteristics, mortality, and causes of death among the enrolled subjects based on the time of ART initiation. Cox regression analysis was used to estimate the adjusted hazard ratios of mortality based on the time of ART initiation. @*Results@#Among the 2474 patients enrolled, 105 (4.24%) died during the follow-up period of 9568 patient-years. Although CD4 cell counts at the time of ART initiation significantly increased from 161 [interquartile range (IQR), 73.5–303] in 2001–2003 to 273 (IQR, 108–399) in 2013–2015 (p40 years [adjusted hazard ratio, 3.71; 95% confidence interval (CI), 2.35–5.84] and low CD4 counts (<100 cells/mm3: adjusted hazard ratio, 2.99; 95% CI, 1.44–6.23) were significant risk factors for mortality. @*Conclusion@#Despite excellent HIV care available in the recent ART era, the survival of patients with HIV/AIDS undergoing ART did not improve between 2001 and 2015 in Korea.

Clinical Significance of a High SARS-CoV-2 Viral Load in the Saliva

Background@#Patients with coronavirus disease 2019 (COVID-19) can unknowingly spread the virus to several people during the early subclinical period. @*Methods@#We evaluated the viral dynamics in various body fluid specimens, such as nasopharyngeal swab, oropharyngeal swab, saliva, sputum, and urine specimens, of two patients with COVID-19 from hospital day 1 to 9. Additional samples of the saliva were taken at 1 hour, 2 hours, and 4 hours after using a chlorhexidine mouthwash. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load was determined by real-time reverse transcriptase polymerase chain reaction (rRT-PCR). @*Results@#SARS-CoV-2 was detected from all the five specimens of both patients by rRT-PCR. The viral load was the highest in the nasopharynx (patient 1 = 8.41 log10 copies/mL; patient 2 = 7.49 log10 copies/mL), but it was also remarkably high in the saliva (patient 1 = 6.63 log10 copies/mL; patient 2 = 7.10 log10 copies/mL). SARS-CoV-2 was detected up to hospital day 6 (illness day 9 for patient 2) from the saliva of both patients. The viral load in the saliva decreased transiently for 2 hours after using the chlorhexidine mouthwash. @*Conclusion@#SARS-CoV-2 viral load was consistently high in the saliva; it was relatively higher than that in the oropharynx during the early stage of COVID-19. Chlorhexidine mouthwash was effective in reducing the SARS-CoV-2 viral load in the saliva for a short-term period.