Temporal Dynamics of Serum Perforin and Granzyme during the Acute Phase of SARS-CoV-2 Infection.

BACKGROUND: As many SARS-CoV-2 infections are asymptomatic, it could be useful to be able to determine how much time has passed since infection. We explored the changes in the temporal levels of T cell-related proteins (including perforin and granzymes) in the sera of patients with SARS-CoV-2 infection using a commercially available assay. METHODS: This study enrolled 36 patients infected with SARS-CoV-2 and 20 healthy control participants. Blood samples were collected at three different times based on the number of days since symptom onset (early phase: 1-5 days, mid-phase: 6-10 days, late phase: 11-18 days). We assessed the temporal changes in the serum levels of perforin and granzymes in patients with SARS-CoV-2 infection by comparing the results with those obtained in the healthy control group. RESULTS: We identified a significantly low level of perforin in the early phase of SARS-CoV-2 infection (p < 0.01), which was restored to normal during the mid- and late phases of the infection. However, there was no difference in the temporal change in the level of granzymes in SARS-CoV-2-infected patients compared to the healthy control group. CONCLUSIONS: This finding suggests that SARS-CoV-2 infection paralyzed the perforin expression in the early period immediately after infection. Thus, serum perforin is a potential marker for identifying the acute phase of SARS-CoV-2 infection.

Temporal Dynamics of Serum Perforin and Granzymes in Three Different Clinical Stages of Virus-Induced Severe Fever with Thrombocytopenia Syndrome.

Virus-induced severe fever with thrombocytopenia syndrome (SFTS) induces a cell-mediated immune response that likely contributes to virus control in SFTS patients. To identify the temporal changes of the cell-mediated immune response, we investigated the changes in serum levels of perforin and granzymes at early periods after illness onset in SFTS patients. We analyzed 32 SFTS patients and compared the temporal patterns of serum perforin and granzyme A and B to that of 20 healthy control adults using the Mann-Whitney U test. Compared with healthy controls, the mean level of perforin was significantly reduced by 81% (P < 0.01) during the first week after illness onset, whereas granzyme B significantly increased by 4.6-fold (P = 0.02) in the first week after illness onset and decreased to normal afterward. During the study period, there was no significant difference in serum perforin and granzyme. These findings indicate that perforin and granzyme B in serum can be considered possible serologic markers that reflect the clinical stage of SFTS. Additional study is warranted for tracking circulating perforin and granzyme in different ages and for an extended period after illness onset.

Association of public health and social measures on the hand-foot-mouth epidemic in South Korea.

BACKGROUND: School based-measures such as school closure and school holidays have been considered a viable intervention during the hand-foot-mouth disease (HFMD) epidemic. The aim of this study was to explore the association of nationwide public health and social measures (PHSMs) including planned school vacation on the transmissibility and attack rate of the HFMD epidemic in South Korea. METHODS: In this study, we used Korean national surveillance data on HFMD from 2014 to 2019 to estimate the temporal changes in HFMD transmissibility (instantaneous reproductive number, Rt). Furthermore, to assess the changes in the HFMD attack rate, we used a stochastic transmission model to simulate the HFMD epidemic with no school vacation and nationwide PHSMs in 2015 South Korea. RESULTS: We found that school vacations and 2015 PHSMs were associated with the reduced Rt by 2-7 % and 13 %, respectively. Model projections indicated school vacations and 2015 PHSMs were associated with reduced HFMD attack rate by an average of 1.10 % (range: 0.38-1.51 %). CONCLUSIONS: PHSMs likely have a larger association with reduced HFMD transmissibility than school-based measures alone (i.e. school vacations). Preventive measures targeting preschoolers could be considered as potential options for reducing the future burden of HFMD.

Pediatric humoral immune responses and infection risk after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and two-dose vaccination during SARS-CoV-2 omicron BA.5 and BN.1 variants predominance in South Korea.

Background: Humoral immune responses and infection risk after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and coronavirus disease 2019 (COVID-19) vaccination during the Omicron BA.5 and BN.1 variants predominant period remains unexplored in pediatric population. Methods: We examined anti-spike (anti-S) immunoglobulin G (IgG) responses in a total of 986 children aged 4-18 years who visited outpatient clinics between June 2022 and January 2023, with a history of SARS-CoV-2 infection alone, completed two doses of COVID-19 vaccination alone, vaccine-breakthrough infection (i.e., infection after the single dose of vaccination), and no antigenic exposure. Furthermore, to determine SARS-CoV-2 infection risk, the incidence of newly developed SARS-CoV-2 infection was investigated up to March 2023. Results: The anti-S IgG levels in the 'vaccine-breakthrough infection' group exceeded those in the 'infection alone' and 'vaccination alone' groups (both P <0.01). Furthermore, the 'vaccination alone' group experienced more rapid anti-S IgG waning than the 'infection alone' and 'vaccine-breakthrough infection' groups (both P <0.01). We could not identify newly developed SARS-CoV-2 infection in the 'vaccine-breakthrough infection' group. Conclusion: Our findings suggest that hybrid immunity, acquired from SARS-CoV-2 infection and COVID-19 vaccination, was a potentially higher and longer-lasting humoral immune response and protected against SARS-CoV-2 infection in pediatric population during Omicron BA.5 and BN.1 variants predominant.

Incubation period of wild type of SARS-CoV-2 infections by age, gender, and epidemic periods.

Background: The incubation period of the coronavirus disease 2019 (COVID-19) is estimated to vary by demographic factors and the COVID-19 epidemic periods. Objective: This study examined the incubation period of the wild type of SARS-CoV-2 infections by the different age groups, gender, and epidemic periods in South Korea. Methods: We collected COVID-19 patient data from the Korean public health authorities and estimated the incubation period by fitting three different distributions, including log-normal, gamma, and Weibull distributions, after stratification by gender and age groups. To identify any temporal impact on the incubation period, we divided the study period into two different epidemic periods (Period-1: 19 January-19 April 2020 and Period-2: 20 April-16 October 2020), and assessed for any differences. Results: We identified the log-normal as the best-fit model. The estimated median incubation period was 4.6 (95% CI: 3.9-4.9) days, and the 95th percentile was 11.7 (95% CI: 10.2-12.2) days. We found that the incubation period did not differ significantly between males and females (p = 0.42), age groups (p = 0.60), and the two different epidemic periods (p = 0.77). Conclusions: The incubation period of wild type of SARS-CoV-2 infection during the COVID-19 pandemic 2020, in South Korea, does not likely differ by age group, gender and epidemic period.

Quality of Life and Associated Factors of International Students in South Korea: A Cross-Sectional Study Using the WHOQOL-BREF Instrument.

The quality of life (QoL) of an individual is affected in a complex way by the person's physical health, psychological state, social relationships, and their relationship to their environment. We assessed the QoL of international university students using the World Health Organization Quality of Life (WHOQOL-BREF) tool and explored the QoL-associated factors. We conducted a cross-sectional study between January and March 2021. The WHOQOL-BREF was summarized as a four-domain construct following the WHO guidelines and QoL scores for each domain were compared through a t-test and chi-squared test. To determine the factors associated with international students' QoL we used multiple linear regression models, with each of the domains serving as the outcome variable. In total, 261 students participated, with 52.5% being males. We reported predicted means (PM) along with 95% confidence intervals (CI). Cronbach's alpha for the overall WHOQOL-BREF tool was 0.88. Students' self-reported QoL mean score was 3.67 ± 0.71 and the mean score of their overall satisfaction with health was 3.61 ± 0.83. The social relationships domain had the highest mean score at 56.88 ± 19.55 and was significantly associated with age (>25 years: PM: 59.7; 95% CI: 56.2−63.2, p = 0.033) and region of origin (Asia: PM: 54.4; 95% CI: 42.5−64.8, p = 0.027). Students above 25 years had significantly higher scores in all domains (p < 0.05). Our results showed that the social relationships and psychological health domains have more positive impact on international students' QoL compared to the physical and environmental health domains. To cope with factors influencing international students' QoL, universities should develop and provide efficient support systems for foreign students in South Korea.

Collateral Impact of Public Health and Social Measures on Respiratory Virus Activity during the COVID-19 Pandemic 2020-2021.

Many countries have implemented public health and social measures (PHSMs) to control the spread of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Although the PHSMs are targeted at SARS-CoV-2 transmission control, they directly or indirectly impact the epidemiology of different respiratory viral diseases. The purpose of this study was to investigate the collateral impact of PHSMs used during the coronavirus disease 2019 (COVID-19) pandemic on the epidemiology of other respiratory viruses, including influenza, parainfluenza, respiratory syncytial virus, rhinovirus, and adenovirus infections. We conducted a systematic review of the published literature on changes in the incidence of respiratory viral diseases and detection rates of the respiratory viruses during COVID-19 pandemic, lasting from 2020-2021, published between December 2019 and March 2022 in PubMed, Embase, and Cochrane Library databases. We identified an overall decrease of 23-94% in the incidence of respiratory viral diseases and a decrease of 0-98% in the detection of the viruses. Our study suggests that the PHSMs implemented during COVID-19 pandemic reduced the incidence of respiratory viral diseases and transmission of respiratory viruses. At the time of this study, and as governments relax PHSMs, public health authorities should prepare for a probable increase in the burden of respiratory viral diseases.

Water quality of improved water sources and associated factors in Kibuku District, Eastern Uganda.

Globally, billions of people still lack access to safe water, including basic drinking water services, particularly in sub-Saharan Africa. We analyzed water quality for improved water sources and associated factors in Kibuku district, Eastern Uganda. The mixed-methods study employed included; water quality analysis, a questionnaire survey, and key informant interviews conducted in the months of April-June 2020. A total of 249 improved water sources were sampled for analysis of bacteriological quality, pH, and electrical conductivity. This was followed by a sanitary and people's attitudes survey at all the water sources visited. Among the water sources, 62.3% deep boreholes, 63.5% public tap stands, 14.3% rain-water harvesting tanks, and 28.6% protected springs had zero thermotolerant coliforms with 63.8% having acceptable pH levels (6.5-8.5) and 35.3% having acidic levels (less than 6.4). Furthermore, 96.3% deep boreholes, 99.1% public tap stands, all (100%) rain-water harvesting tanks, and 50% protected springs had their turbidity levels in the acceptable range (less than 5NTUs). Additionally, only 22.1% of improved water sources had electrical conductivity in the acceptable range (less than 300 microSiemens). Among the 249 participants, majority (91.2%) had low knowledge levels about various methods that can be used in improving the quality of water. Generally, water sources had poor quality of water which was attributed to agricultural activities, dirty water collection containers, and poor attitude to water chlorination. The Ministry of Health, Ministry of Water and Environment, and other agencies need to design sustainable and feasible models for water treatment for low resourced setting.

Transmission Dynamics of the Delta Variant of SARS-CoV-2 Infections in South Korea.

BACKGROUND: The Delta variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was the predominant variant worldwide at the time of this study. However, its transmission dynamics were unclear. METHODS: We analyzed 405 local cases infected with the Delta variant of SARS-CoV-2 and temporal patterns of viral shedding identified between 22 June and 31 July 2021 in Daejeon, South Korea. RESULTS: Overall, 20% were presymptomatic at the time of epidemiological investigation. We identified 6 clustered outbreaks, and all were associated with indoor facilities. In 23 household contacts, the secondary attack rate was 63%. We estimated the mean serial interval as 3.26 days (95% credible interval, 2.92-3.60), and 15% (95% confidence interval, 13%-18%) of cases seeded 80% of all local transmission. Analysis of the nasopharyngeal swab samples identified virus shedding from the presymptomatic cases and the highest viral load was observed 2 days after symptom onset. CONCLUSIONS: Our findings suggest that the Delta variant is highly transmissible in indoor settings and households. Rapid contact tracing, isolation of the asymptomatic contacts, strict adherence to public health measures, and increased uptake of coronavirus disease 2019 (COVID-19) vaccination, including booster doses, are needed to reduce community transmission of the Delta variant.

Adverse Effects of Smartphone Addiction among University Students in South Korea: A Systematic Review.

BACKGROUND: Globally there has been an exponential increase in the penetration of smartphones among the youth population and smartphones have become indispensable in the daily lives of university students in South Korea. Several studies have associated the problematic use of smartphones or addiction with different adverse outcomes. The goal of this study was to collate empirical evidence and provides an overall synthesis of the literature about the adverse effects of smartphone addiction on university students in South Korea. METHOD: We carried out a systematic review of the published literature between August and October 2022 on the adverse effects of smartphone addiction on university students in South Korea, published between 2012 and 2022 in Pubmed/Medline, PsycInfo, Embase, Biomed-Central, Web of Science, Directory of Open Access Journals, Elsevier's collection, Wiley Online Library, SpringerLink, Sage Journal's collection and Cochrane Library. RESULTS: Thirty-four articles published between 2012 and 2022 were included in the synthesis of this review. Eight studies explored the association between smartphone addiction and the psychological and mental health of university students in Korea. Smartphone addiction was associated with physical health leading to sleep disorders and musculoskeletal and neurological problems. Academic performance, procrastination, impulsivity, self-esteem, reduced social interaction, solitude, and suicide were also negatively associated with smartphone addiction. CONCLUSIONS: Our study adds to the literature regarding the adverse effects of smartphone addiction on university students in Korea and provides more information for addiction prevention and health promotion activities.

Acceptance of the COVID-19 Vaccine by Foreigners in South Korea.

Vaccination against COVID-19 is an important strategy for its control. Assessing the willingness to accept the COVID-19 vaccine in different subgroups is important for an inclusive vaccination program design. Our aim was to determine the COVID-19 vaccine acceptance rate and associated factors among foreigners in South Korea. An online cross-sectional study was carried out from May to June 2021. In this study, 710 individuals participated and most were aged between 26 and 29 (36.1%) years. Overall, 70.8% were willing to receive the vaccine. Males were less likely to accept the vaccine than females (OR: 0.5; 95% CI: 0.4-0.7, p < 0.001). Single people were more likely to receive the vaccine than those who were married (OR: 1.4; 95% CI: 0.9-2.0, p = 0.04). Other factors associated with willingness to accept COVID-19 vaccine were; vaccine convenience (OR: 1.7; 95% CI: 1.2-2.3, p = 0.002), doctors' recommendation (OR: 2.8; 95% CI: 2.0-3.9, p < 0.001), vaccine price (OR: 1.7; 95% CI: 1.2-2.3, p = 0.003), vaccine effectiveness (OR: 8.3; 95% CI: 5.8-12.1, p < 0.001), vaccine importance (OR: 7.9; 95% CI: 4.6-14.1, p < 0.001), and vaccine safety (OR: 6.9; 95% CI: 4.5-10.8, p < 0.001). Providing more information on vaccine safety and effectiveness is required to increase vaccine acceptance.

Measles outbreak in Western Uganda: a case-control study.

BACKGROUND: Measles outbreaks are prevalent throughout sub-Saharan Africa despite the preventive measures like vaccination that target under five-year-old children and health systems strengthening efforts like prioritizing the supply chain for supplies. Measles immunization coverage for Kasese district and Bugoye HC III in 2018 was 72 and 69%, respectively. This coverage has been very low and always marked red in the Red categorization (below the national target/poor performing) on the national league table indicators. The aim of this study was to assess the scope of the 2018-2019 measles outbreak and the associated risk factors among children aged 0-60 months in Bugoye sub-county, Kasese district, western Uganda. METHODS: We conducted a retrospective unmatched case-control study among children aged 0-60 months with measles (cases) who had either a clinical presentation or a laboratory confirmation (IgM positivity) presenting at Bugoye Health Centre III (BHC) or in the surrounding communities between December 2018 and October 2019.. Caregivers of the controls (whose children did not have measles) were selected at the time of data collection in July 2020. A modified CDC case investigation form was used in data collection. Quantitative data was collected and analyzed using Microsoft excel and STATA version 13. The children's immunization cards and health registers at BHC were reviewed to ascertain the immunization status of the children before the outbreak. RESULTS: An extended measles outbreak occurred in Bugoye, Uganda occured between December 2018 and October 2019. All 34 facility-based measles cases were documented to have had maculopapular rash, conjunctivitis, and cough. Also, the majority had fever (97%), coryza (94.1%), lymphadenopathy (76.5%), arthralgias (73.5%) and Koplik Spots (91.2%) as documented in the clinical registers. Similar symptoms were reported among 36 community-based cases. Getting infected even after immunized, low measles vaccination coverage were identified as the principal risk factors for this outbreak. CONCLUSION: Measles is still a significant problem. This study showed that this outbreak was associated with under-vaccination. Implementing a second routine dose of measles-rubella vaccine would not only increase the number of children with at least one dose but also boost the immunity of those who had the first dose.