OBJECTIVES: Since the report of the first confirmed case in Daegu on February 18, 2020, local transmission of coronavirus disease 2019 (COVID-19) in Korea has continued. In this study, we aimed to identify the pattern of local transmission of COVID-19 using mathematical modeling and predict the epidemic size and the timing of the end of the spread. METHODS: We modeled the COVID-19 outbreak in Korea by applying a mathematical model of transmission that factors in behavioral changes. We used the Korea Centers for Disease Control and Prevention data of daily confirmed cases in the country to estimate the nationwide and Daegu/Gyeongbuk area-specific transmission rates as well as behavioral change parameters using a least-squares method. RESULTS: The number of transmissions per infected patient was estimated to be about 10 times higher in the Daegu/Gyeongbuk area than the average of nationwide. Using these estimated parameters, our models predicts that about 13,800 cases will occur nationwide and 11,400 cases in the Daegu/Gyeongbuk area until mid-June. CONCLUSIONS We mathematically demonstrate that the relatively high per-capita rate of transmission and the low rate of changes in behavior have caused a large-scale transmission of COVID-19 in the Daegu/Gyeongbuk area in Korea. Since the outbreak is expected to continue until May, non-pharmaceutical interventions that can be sustained over the long term are required.

OBJECTIVES: Since the report of the first confirmed case in Daegu on February 18, 2020, local transmission of coronavirus disease 2019 (COVID-19) in Korea has continued. In this study, we aimed to identify the pattern of local transmission of COVID-19 using mathematical modeling and predict the epidemic size and the timing of the end of the spread. METHODS: We modeled the COVID-19 outbreak in Korea by applying a mathematical model of transmission that factors in behavioral changes. We used the Korea Centers for Disease Control and Prevention data of daily confirmed cases in the country to estimate the nationwide and Daegu/Gyeongbuk area-specific transmission rates as well as behavioral change parameters using a least-squares method. RESULTS: The number of transmissions per infected patient was estimated to be about 10 times higher in the Daegu/Gyeongbuk area than the average of nationwide. Using these estimated parameters, our models predicts that about 13,800 cases will occur nationwide and 11,400 cases in the Daegu/Gyeongbuk area until mid-June. CONCLUSIONS We mathematically demonstrate that the relatively high per-capita rate of transmission and the low rate of changes in behavior have caused a large-scale transmission of COVID-19 in the Daegu/Gyeongbuk area in Korea. Since the outbreak is expected to continue until May, non-pharmaceutical interventions that can be sustained over the long term are required.

PURPOSE: To investigate the effect of prophylactic intraocular pressure (IOP)-lowering medication after intravitreal dexamethasone implantation. METHODS: This is a retrospective analysis of 39 eyes undergoing intravitreal dexamethasone implantation for macular edema. Eyes were divided into two groups, those which had used prophylactic IOP-lowering medication and those which had not. IOP was measured preoperatively, at one week, and monthly until six months post-injection in each group. RESULTS: The mean pre-injection IOP for the group that had not used prophylactic IOP-lowering medication and the group that had was 13.95 +/- 3.32 mm Hg and 13.56 +/- 3.71 mm Hg, the mean post-injection IOP at two months was 15.81 +/- 3.75 mm Hg and 12.56 +/- 5.02 mm Hg, and that at six months was 12.90 +/- 2.95 mm Hg and 11.44 +/- 3.59 mm Hg, respectively. The difference between the two groups was statistically significant at one week, one month, two months, and three months (p = 0.001, 0.002, 0.011, 0.035, respectively). A greater than 22 mm Hg increase in IOP was seen in four eyes (19.05%) in the group that had not used IOP-lowering medication and in one eye (5.56%) in the group that had. A greater than 5 mm Hg increase in IOP from baseline was seen in eight eyes (38.10%) in the group that had not used IOP-lowering medication and in one eye (5.56%) in the group that had. CONCLUSIONS: After intravitreal dexamethasone implantation, prophylactic IOP-lowering medication will significantly prevent IOP increase and decrease the number of patients requiring additional treatment that could cause potential damage to the retina and optic nerve.
Dexamethasone* ; Humans ; Intraocular Pressure ; Macular Edema ; Optic Nerve ; Retina ; Retrospective Studies

PURPOSE: To investigate the effect of prophylactic intraocular pressure (IOP)-lowering medication after intravitreal dexamethasone implantation. METHODS: This is a retrospective analysis of 39 eyes undergoing intravitreal dexamethasone implantation for macular edema. Eyes were divided into two groups, those which had used prophylactic IOP-lowering medication and those which had not. IOP was measured preoperatively, at one week, and monthly until six months post-injection in each group. RESULTS: The mean pre-injection IOP for the group that had not used prophylactic IOP-lowering medication and the group that had was 13.95 +/- 3.32 mm Hg and 13.56 +/- 3.71 mm Hg, the mean post-injection IOP at two months was 15.81 +/- 3.75 mm Hg and 12.56 +/- 5.02 mm Hg, and that at six months was 12.90 +/- 2.95 mm Hg and 11.44 +/- 3.59 mm Hg, respectively. The difference between the two groups was statistically significant at one week, one month, two months, and three months (p = 0.001, 0.002, 0.011, 0.035, respectively). A greater than 22 mm Hg increase in IOP was seen in four eyes (19.05%) in the group that had not used IOP-lowering medication and in one eye (5.56%) in the group that had. A greater than 5 mm Hg increase in IOP from baseline was seen in eight eyes (38.10%) in the group that had not used IOP-lowering medication and in one eye (5.56%) in the group that had. CONCLUSIONS: After intravitreal dexamethasone implantation, prophylactic IOP-lowering medication will significantly prevent IOP increase and decrease the number of patients requiring additional treatment that could cause potential damage to the retina and optic nerve.
Dexamethasone* ; Humans ; Intraocular Pressure ; Macular Edema ; Optic Nerve ; Retina ; Retrospective Studies

Background: For protection against coronavirus disease 2019 (COVID-19), the Korean government recommended the KF94 mask or that a mask at the same level as the KF94 should be worn when contacting a patient with COVID-19. Furthermore, adequately fitted N95 respirators and KF94 masks are essential. We investigated the fit tests to determine whether healthcare workers had adequate protection with N95 respirators and KF94 masks. Methods: In this prospective single-center simulation study, five N95 respirators (two made in the USA by 3M and three made in Korea) and six KF94 masks, the Korean standard medical masks, were tested. The fit factor (FF) and leakage rate were evaluated using a two-fit test device. Adequate protection (defined as FF ≥ 100 or leakage rate ≤ 5) rates were compared between N95 respirators and KF94 masks, and between made in Korea and the 3M N95 respirators. For KF94 masks, adequate protection rates were compared before and after ear strap fixation. Results: Overall, 30 participants were enrolled, and 330 fit tests were performed for FF and leakage rate. Adequate protection rates of all tested N95 respirators and KF94 masks were 22.7% (n = 75) by FF and 20.6% (n = 68) by leakage rate. N95 respirators showed a significantly higher adequate protection rate than KF94 masks for FF (48.7% vs. 1.1%, P < 0.001) and leakage rate (42.0% vs. 2.8%, P < 0.001). Adequate protection rate of 3M-made N95 respirators was significantly higher than that of those made in Korea (83.3% vs. 25.6% in FF, P < 0.001; 73.3% vs. 21.1% in leakage rate, P < 0.001). In KF94 masks, after fixation of ear strap with a hook, adequate protection rate improved significantly (1.1% vs. 12.8% in FF, P< 0.001; 2.8% vs. 11.1%, P < 0.001). Conclusion Although adequate protection rate of N95 respirators was higher than that of KF94 masks, N95 respirator protection rate was not optimum. Thus, it is necessary to minimize exposure to risk by selecting an appropriate mask or respirator that adequately fits each person, and by wearing respirators or masks appropriately, before contacting the patients. With their superior protection rate, wearing N95 respirators is recommended instead of KF94 masks, especially when performing aerosol-generating procedures.

Purpose: Both allergic rhinitis and asthma are considered one airway disease, which interacts with each other in disease onset and symptom worsening. We evaluated factors developing new or persistent asthma symptoms in elementary school children with allergic rhinitis. Methods: We selected 343 children aged 6 to 7 years who had rhinitis symptoms within 12 months and allergic sensitization on skin prick tests among 2,491 elementary school children. The questionnaires on symptoms, medical history and environments, blood eosinophils, serum total IgE, pulmonary function test, and bronchial provocation tests were obtained. Using multiple regression analysis, we evaluated factors for later asthma symptoms during a follow-up period of 4 years. Results: The independent risk factors for later asthma symptoms among children with allergic rhinitis were higher body mass index (adjusted odds ratio [aOR], 1.29; 95% confidence interval [CI], 1.06–1.56; P= 0.012), a parental diagnosis of asthma (aOR, 6.19; 95% CI, 1.59–24.06; P= 0.008), residence in the rural area (aOR, 5.37; 95% CI, 1.34–21.42; P= 0.017), and a history of bronchiolitis in the first 2 years (aOR, 5.82; 95% CI, 1.42–23.80; P= 0.014). However, pulmonary functions, the levels of bronchial hyper-responsiveness, and the patterns of sensitization showed not significant factors. Children whose allergic rhinitis was treated in the follow-up period were less likely to have asthma symptoms later (aOR, 0.30; 95% CI, 0.10–0.93; P= 0.036). Conclusion In the school-aged children with allergic rhinitis, body mass index and asthma-related risk factors are crucial for developing asthma symptoms. The appropriate treatment of rhinitis may decrease asthma symptoms.