Gender differences in hepatitis A seropositivity rates according to the Republic of Korea's vaccination policy.

BACKGROUND: This study aimed to investigate differences in the anti-hepatitis A virus (HAV) antibody seropositivity rate by age and gender. METHODS: We collected information on anti-HAV immunoglobulin G and immunoglobulin M status from samples submitted for HAV antibody testing in 2012-2022. A total of 1,333,615 cases were included in the analysis. RESULTS: By age, the seropositivity rate was represented by a U-shaped curve, such that the rate was low for the group aged 20 to 39 years and higher in those who were younger or older. Over time, the curve shifted rightward, and the seropositivity rate declined gradually in the group aged 35 to 39 years and older. A gender-based difference in antibody seropositivity rate was especially noticeable in the group aged 20 to 29 years. This difference between genders widened in the participants' early 20s-when men in the Republic of Korea enlist in the military-and the divergence continued subsequently for older individuals. CONCLUSION: These results indicate a higher risk of severe infection among older individuals and a gender-based difference in seroprevalence. Therefore, it is necessary to implement policies to promote vaccination in adults.

Association between Changes in Daily Life Due to COVID-19 and Depressive Symptoms in South Korea.

We aimed to examine changes in daily life due to coronavirus disease 2019 (COVID-19) among younger (≤64 years) and older (≥65 years) individuals and to analyze their association with depressive symptoms. Raw data from the 2020 Korean Community Health Survey were used to analyze 228,485 individuals. Changes in daily life due to COVID-19 were measured using a questionnaire that evaluated changes in physical activity, sleep duration, instant food intake, and drinking and smoking status. Depressive symptoms were assessed using the Patient Health Questionnaire 9 scale, and logistic regression analysis was performed to explore the association between the two variables. This study confirmed a significant association between the two variables and found that the intake of instant food showed the largest difference in odds ratios between the younger (OR: 1.851; 95% CI: 1.720-1.992) and older groups (OR: 1.239; 95% CI: 1.060-1.447). A major finding of this study is that the analysis of the association between the two variables revealed a stronger correlation in more variables in the younger population compared to the older population. To address COVID-19-related depression and prepare for potential mental health crises, countries should expand response measures.

Predictors, mortality, and health outcomes of intensive phase non-adherence to a regimen in patients with drug-susceptible tuberculosis: a nationwide linkage database.

OBJECTIVES: The clinical importance of adhering to the regimen in tuberculosis patients has been widely investigated, but most studies were conducted in controlled settings and in limited populations. We aimed to measure the level of real-world adherence during intensive phase and investigate the predictors and the risk of mortality and health outcomes of intensive phase non-adherence in tuberculosis patients. STUDY DESIGN: We conducted a nationwide cohort study by linking the Korean National Tuberculosis Surveillance System and the National Health Information Database. METHODS: We included all incident drug-susceptible tuberculosis patients who initiated the regimens recommended by the World Health Organization from 2013 to 2018. Adherence was measured using the proportion of days covered (poor [<50%], moderate [50%-79%], and high [≥80%]). We used logistic regression model to assess predictors and the Cox proportional hazard model to evaluate the risk of mortality and health outcomes with intensive phase non-adherence. RESULTS: Of 46,818 patients, there were 8% and 11% with poor and moderate adherent groups, respectively. Age ≥45 years, insulin use, and history of renal failure were predictors of non-adherence. Compared with high adherent group, poor and moderate adherent groups were associated with a substantial risk of mortality (poor: hazard ratio, 2.14 [95% confidence interval, 1.95-2.34]; moderate: 1.76 [1.62-1.92]). Similar trends were observed for health outcomes. Stratified analyses showed a higher risk of mortality in patients with medical aid, low income, and history of renal failure, systematic corticosteroids, and immunomodulators. CONCLUSIONS: Non-adherence during intensive phase increased mortality risk by twofold, underscoring targeted intervention for high-risk population, including advanced diabetes, and immunocompromised patients.

Temporal Trends in Syphilis Incidence among Men with HIV in Busan, Korea, 2005-2022: A Retrospective Cohort Study.

We aimed to assess the temporal trends of incident syphilis and its associated risk factors among men with HIV (Human Immunodeficiency Virus) in Korea during the COVID-19 pandemic. We conducted a retrospective cohort study of men with HIV attending an HIV clinic in Korea between 2005 and 2022. Of 767 men with HIV, 499 were included and contributed 3220 person-years (PY) of the observation period. Eighty-two patients were diagnosed with incident syphilis, with an overall incidence of 2.55/100 PY (95% confidence interval [CI] 20.56-31.53). The incidence of syphilis per 100 PY gradually decreased from 2.43 (0.79-7.42) in 2005-2007 to 1.85 (1.08-3.17) in 2014-2016; however, it increased to 3.0 (1.99-4.53) in 2017-2019, and further to 3.33 (2.26-4.89) in 2020-2022. A multivariate analysis identified young age (≤30 years versus >50, adjusted HR 6.27, 95% CI 2.38-16.56, p < 0.001), treponemal test positive at baseline (2.33, 1.48-3.67, p < 0.001), men who have sex with men (2.36, 1.34-4.16, p = 0.003), and history of incarceration (2.62, 1.21-5.67, p = 0.015) as risk factors for incident syphilis. Recently, syphilis incidence in men with HIV has increased in Korea, especially in young patients and at-risk groups, highlighting the need for enhanced regular screening and targeted behavioral interventions among these populations.

Characterization of nickel levels considering seasonal and intra-individual variation using three biological matrices.

Nickel compounds are classified as group 1 carcinogens by the International Agency for Research on Cancer. However, only a few exposure assessment studies have been conducted on such compounds to date. In this study, we investigated the distribution of nickel in three biological types of samples (blood, serum, and urine) and its temporal variability through repeated measurements. From 2020 to 2021, blood and urine samples were collected for four times from 50 healthy participants. Nickel concentrations were determined using inductively coupled plasma mass spectrometry, and inter-individual correlation was calculated from linear mixed model. The overall geometric mean of nickel was 1.028 µg/L in blood, 0.687 µg/L in serum, and 1.464 µg/L in urine. Blood nickel was the highest in November (blood: 1.197 µg/L), and the geometric mean of nickel concentrations in the serum and urine were the highest in March (serum: 1.146 µg/L; urine: 1.893 µg/L). This matched seasonal trends for fine particulate matter concentrations from 2020 to 2021. Thus, seasonal effects significantly affect nickel levels in blood, serum, and urine. The inter-individual correlations were low as 0.081 for blood and 0.064 for urine. In addition, the correlation of nickel levels between each biological sample was low. It was also found that age, gender, commuting time, and different matrices affect concentrations. Blood and serum nickel levels were high in this study compared to other nationwide data, with urinary nickel ranking the second highest among the six countries examined. Therefore, biomonitoring study in the general population should be conducted, and finding a suitable matrix that can reflect nickel exposure to set exposure guideline levels is imperative.

Improved time-varying reproduction numbers using the generation interval for COVID-19.

Estimating key epidemiological parameters, such as incubation period, serial interval (SI), generation interval (GI) and latent period, is essential to quantify the transmissibility and effects of various interventions of COVID-19. These key parameters play a critical role in quantifying the basic reproduction number. With the hard work of epidemiological investigators in South Korea, estimating these key parameters has become possible based on infector-infectee surveillance data of COVID-19 between February 2020 and April 2021. Herein, the mean incubation period was estimated to be 4.9 days (95% CI: 4.2, 5.7) and the mean generation interval was estimated to be 4.3 days (95% CI: 4.2, 4.4). The mean serial interval was estimated to be 4.3, with a standard deviation of 4.2. It is also revealed that the proportion of presymptomatic transmission was ~57%, which indicates the potential risk of transmission before the disease onset. We compared the time-varying reproduction number based on GI and SI and found that the time-varying reproduction number based on GI may result in a larger estimation of Rt, which refers to the COVID-19 transmission potential around the rapid increase of cases. This highlights the importance of considering presymptomatic transmission and generation intervals when estimating the time-varying reproduction number.

Characteristics of Critically Ill COVID-19 Patients in Busan, Republic of Korea.

BACKGROUND: This study aimed to improve the clinical course of patients through rapid response by analyzing the characteristics of critically ill patients with confirmed coronavirus disease 2019 (COVID-19) in Busan between December 1, 2020, and December 31, 2021. METHODS: We divided patients diagnosed with COVID-19 into mild-to-moderate and critical groups based on their clinical severity. The critically ill patients were further sub-divided into delta and delta variant non-epidemic group. RESULTS: The following factors were significantly more frequent in critically ill patients than in patients with mild-tomoderate symptoms: male sex, age ≥60 years, symptoms at the time of diagnosis, and those with underlying diseases. The following factors were significantly more common in the non-delta variant epidemic group than in the delta variant epidemic group in critically ill patients: male sex, age ≥60 years, underlying diseases, and not being vaccinated. In the delta variant epidemic group, the duration between confirmation of disease and its progression to critically ill status was significantly shorter than that in the non-delta variant epidemic group. CONCLUSION: COVID-19 is characterized by the emergence of new variants and repeated epidemics. Therefore, it is necessary to analyze the characteristics of critically ill patients to efficiently distribute and manage medical resources.

Comparative safety of bedaquiline and delamanid in patients with multidrug resistant tuberculosis: A nationwide retrospective cohort study.

BACKGROUND/PURPOSE(S): Bedaquiline and delamanid were recently approved for multidrug resistant tuberculosis (MDR-TB). Bedaquiline carries a black box warning of increased risk of death compared to the placebo arm, and there is a need to establish the risks of QT prolongation and hepatotoxicity for bedaquiline and delamanid. METHODS: We retrospectively analyzed data of MDR-TB patients retrieved from the South Korea national health insurance system database (2014-2020) to assess the risks of all-cause death, long QT-related cardiac event, and acute liver injury associated with bedaquiline or delamanid, compared with conventional regimen. Cox proportional hazards models were used to estimate hazard ratios (HR) with 95% confidence intervals (CI). Stabilized inverse probability of treatment weighting based on propensity score was used to balance characteristics between the treatment groups. RESULTS: Of 1998 patients, 315 (15.8%) and 292 (14.6%) received bedaquiline and delamanid, respectively. Compared with conventional regimen, bedaquiline and delamanid did not increase risk of all-cause death at 24-month (HR 0.73 [95% CI, 0.42-1.27] and 0.89 [0.50-1.60], respectively). Bedaquiline-containing regimen increased risk of acute liver injury (1.76 [1.31-2.36]), while delamanid-containing regimen increased risk of long QT-related cardiac events (2.38 [1.05-3.57]) within 6 months of treatment. CONCLUSION: This study adds to the emerging evidence refuting the higher mortality rate observed in the bedaquiline trial population. Association between bedaquiline and acute liver injury needs careful interpretation considering for other background hepatotoxic anti-TB drugs. Our finding on delamanid and long QT-related cardiac events suggest careful risk-benefit assessment in patients with pre-existing cardiovascular disease.

Evaluation of the accessibility and its equity of the national public-private mix program for tuberculosis in Korea: a multilevel analysis.

OBJECTIVES: To examine the effect of individual and area-level characteristics on the probability of public-private mix (PPM) support (PPM coverage) for tuberculosis (TB). METHODS: This study is a retrospective cohort design using TB reporting and treatment management data in Korea. We analyzed PPM coverage through multilevel logistic regression and empirical Bayesian estimation according to individual and area-level characteristics and their interaction. RESULTS: Patients aged 0-29 years, women, of Korean nationality, treated at a general hospital, a one-time reporting, urban areas, and the lowest deprivation index (DI) showed higher PPM coverage. Due to the cross-level interaction, PPM coverage in the urban areas (slope=-0.048, p<0.001) had a higher level but a steeper negative deprivation gradient than in rural areas (slope= -0.015, p<0.001). For a general hospital, the PPM coverage in urban is high but more significantly decreased than in rural areas with the higher DI (urban: slope=-0.047, p<0.001; rural: slope=-0.031, p<0.001). For clinics and hospitals, the effect of DI did not appear in urban areas, but in rural areas, the higher the DI, the higher the PPM coverage with a slope of 0.046 (p<0.001) and 0.063 (p<0.001), respectively. CONCLUSIONS: The PPM program created a significant disparity in PPM coverage between urban-rural areas and type of healthcare provider according to DI. Considering the high risk of TB incidence in areas with higher DI, institutional improvement and program redesign are needed to improve accessibility and equity.

Changing trends in the incidence and spectrum of cancers between 1990 and 2021 among HIV-infected patients in Busan, Korea.

BACKGROUND: Long-term follow-up data on cancer incidence and spectrum among human immunodeficiency virus (HIV)-infected individuals in Korea have been scarce. MATERIAL AND METHODS: This retrospective cohort study included HIV-infected individuals visiting a tertiary care hospital in Busan, South Korea between 1990 and 2021. The observation was divided into 4 periods. The incidence rate was calculated using direct standardization on age and sex, stratified by calendar period. RESULTS: Of the 1,297 patients, 92 patients (7.1%) were diagnosed with 97 cancers. Excluding 37 patients with prevalent cancer, 1,260 patients were followed for a total of 8,803.7 person-years (PYs), and 55 patients developed 60 incident cancers including 5 second primary incident cancers. In men, the AIDS-defining cancer (ADC) incidence decreased from 294.7 per 100,000 PYs in 1990-1997 to 124.8 per 100,000 PYs in 2014-2021, while the non-AIDS-defining cancer (NADC) incidence increased from 0 per 100,000 PYs to 316.5 per 100,000 PYs during the same period. The proportion of virus-unrelated NADCs (VU-NADCs) increased from 33.3% in 1998-2005 to 49% in 2014-2021. The proportion of human papillomavirus-associated cancers (HPVACs) has recently increased in both ADCs and NADCs. The median time from HIV diagnosis to their first cancer was 1.48 years for ADCs, 6.11 years for VR-NADCs, 8.3 years for VU-NADCs, and 11.5 years for HPVACs. CONCLUSION: The incidence of NADCs is increasing with the aging of HIV-infected patients, and thus, it is necessary to promote cancer screening and prevention programs.

Socioeconomic disparities and multidrug-resistant tuberculosis in South Korea: Focus on immigrants and income levels.

Risk factors of MDR-TB remain unclear in South Korea, despite being an important public health issue. Findings from this study, which included ≥50,000 patients with TB from South Korea, suggests that immigrants and patients with lower income levels were strong predictors of MDR-TB in a high-income, high TB incidence country.

Nationwide population-based incidence of cancer among patients with HIV/AIDS in South Korea.

Cancers are the leading cause of death among people living with HIV/AIDS (PLWHA); however, nationwide studies on cancer incidence are limited. We aimed to determine the trends in the incidence rates of AIDS-defining cancers (ADCs) and non-AIDS-defining cancers (NADCs) among Korean PLWHA. Data from the National Health Insurance Sharing Service from 2004 to 2017 were collected. Age- and sex-adjusted standardized incidence ratios (SIRs) for various cancer types relative to the general population were calculated. Of the 11,737 PLWHA followed-up for 65,052 person-years (PYs), 445 (ADCs, 130 and NADCs, 298) developed cancer. The incidence rate of ADCs decreased, whereas that of NADCs remained unchanged. PLWHA were at an increased risk of ADCs (SIR: 12.6, 95% CI: 10.6-15.0), including Kaposi's sarcoma, non-Hodgkin's lymphoma, and cervical cancer, and some NADCs, including anal cancer, lung cancer, liver cancer, and oropharyngeal cancer. Of the 396 patients who received antiretroviral therapy (ART), 215 with optimal adherence had lower incidence rates for ADCs and NADCs than those with non-optimal adherence. The 5-year survival rate of PLWHA with NADCs was 57.8%. Close surveillance and routine screening of cancers and improvement in ART adherence are required to improve the clinical outcomes of PLWHA.

An outbreak of hepatitis A associated with salted clams in Busan, Korea.

OBJECTIVES: In July 2019, there were multiple reports on patients with hepatitis A among the visitors of a restaurant in Busan. The current study presents the results of an epidemiological investigation and outlines the supplementary measures that would help with hepatitis A control. METHODS: A cohort study was conducted for all 2,865 customers who visited restaurant A from June to July. Using a standardized questionnaire, participants reported the presence of hepatitis A symptoms and whether they had consumed any of 19 food items. As for participants who had visited public health centers, their specimens were collected. RESULTS: From the study cohort, 155 participants (5.4%) had confirmed hepatitis A. The epidemic curve was unimodal, and the median number of days from the restaurant visit to symptom onset was 31 days. A genotype analysis indicated that 89 of 90 tested patients had hepatitis A virus (HAV) genotype 1A. The results of a multivariate logistic regression analysis indicated that the ingestion of salted clams increased the risk of hepatitis A by 68.12 times (95% confidence interval [CI], 9.22 to 510.87). In an unopened package of salted clams found and secured through traceback investigation, HAV genotype 1A was detected. CONCLUSIONS: To prevent people from ingesting uncooked clams, there needs to be more efforts to publicize the dangers of uncooked clams; the food sampling test standards for salted clams should also be expanded. Furthermore, a laboratory surveillance system based on molecular genetics should be established to detect outbreaks earlier.

Temporal trends of pharmacologic treatments for tuberculosis and multidrug resistant tuberculosis following dissemination of treatment guidelines in South Korea.

BACKGROUND/PURPOSE(S): The World Health Organization (WHO) released treatment guidelines for multidrug resistant tuberculosis (MDR-TB) in 2008, with subsequent revisions in 2011; Korea disseminated corresponding guidelines in 2011 and 2014, respectively. Thus, we aimed to investigate the temporal trends of and the updated guideline's impact on the prescription patterns of anti-TB drugs. METHODS: We conducted a time-series study using Korea's nationwide healthcare database (2007-2015), where patients with TB or MDR-TB were included. Only anti-TB drugs prescribed during the intensive phase of treatment for TB (two months) or MDR-TB (eight months) were assessed. We estimated the annual utilization of TB treatment regimens and the relative difference (RD) in the proportion of MDR-TB treatment medications between the following periods: before the first Korean guideline (June 2008 to March 2011); between the first and revised guidelines (April 2011 to July 2014); after the revised guideline (August 2014 to December 2015). RESULTS: Of 3523 TB (mean age 54.1 years; male 56.8%) patients, treatment regimens for TB complied with guideline recommendations as >80% of patients received either quadruple (mean 66.8%) or triple (14.5%) therapy of first-line anti-TB drugs. Following the WHO's guideline update, prescription patterns changed accordingly among 111 MDR-TB (mean age 46.0 years; male 67.6%) patients, as use of pyrazinamide (RD +20.3%) and prothionamide (+11.5%) increased (recommended to be compulsory), and streptomycin (-43.1%) decreased (ototoxicity risks). CONCLUSIONS: Anti-TB drug prescription patterns for both TB and MDR-TB well reflected WHO's treatment guideline as well as corresponding domestic guidelines of South Korea.

Vector-host epidemic model with direct transmission in random environment.

This paper studies a stochastic vector-host epidemic model with direct transmission in random environment, governed by a system of stochastic differential equations with regime-switching diffusion. We first examine the existence and uniqueness of a positive global solution. Then, we investigate stability properties of the solution, including almost sure and pth moment exponential stability and stochastic asymptotic stability. Moreover, we study conditions for the existence and uniqueness of a stationary distribution. Numerical simulations are presented to illustrate the theoretical results.

Precautionary Behavior Practices and Psychological Characteristics of COVID-19 Patients and Quarantined Persons.

BACKGROUND: since the coronavirus disease (COVID-19) was first reported in 2019, South Korea has enforced isolation of patients with confirmed cases of COVID-19, as well as quarantine for close contacts of individuals diagnosed with COVID-19 and persons traveling from abroad, in order to contain its spread. Precautionary behavior practices and psychological characteristics of confirmed and quarantined persons were investigated for planning pandemic recovery and preparedness. METHODS: this study was conducted with 1716 confirmed patients and quarantined persons in Daegu and Busan, regions where a high number of cases were confirmed during the early stage of the COVID-19 outbreak in South Korea. We collected online survey data from 23 April to 20 May 2020, in Daegu, and 28 April to 27 May 2020, in Busan, in cooperation with Daegu and Busan Infectious Disease Control Centers and public health centers in the regions. COVID-19 symptoms, pre-cautionary behavior practices, psychological states, and the need for improvement in isolation/quarantine environments were examined using an online survey. RESULTS: compared to patients infected with coronavirus, quarantined persons engaged in more hygiene-related behaviors (e.g., hand washing, cough etiquette, and proper mask-wearing) and social distancing. COVID-19 patients had a strong fear of stigma, while quarantined persons had a strong fear of contracting COVID-19. Study participants responded that it was necessary to provide financial support and adequate information during isolation/quarantine. CONCLUSIONS: the study highlights the importance of precautionary behavior to prevent COVID-19 infection and the need to provide support (both psychological and financial) to patients and quarantined persons, to reinforce effective communication, social solidarity, and public health emergency preparedness (PHEP) in a pandemic situation.

Status and Determinants of Treatment Outcomes Among New Tuberculosis Patients in South Korea: A Retrospective Cohort Study.

This is a retrospective cohort study using notification data in South Korea. We evaluated the nationwide status, regional differences, and the determinants of treatment outcomes among tuberculosis patients. Treatment success rate improved from 77.0% in 2012 to 86.0% in 2015. The lost to follow-up rate was higher among older people, males, and foreign nationals. Health care facilities designated for the Public-Private Mix (PPM) project showed higher success rate and lower rate of lost to follow-up. Moreover, municipalities with low regional deprivation index had higher PPM project coverage. Since there is a large regional difference in the coverage of the PPM project, an additional community-based support program should be implemented, especially for tuberculosis patients residing in region with low PPM project coverage.

Adherence and Associated Factors of Treatment Regimen in Drug-Susceptible Tuberculosis Patients.

Background: Adherence to tuberculosis (TB) drugs is one of the key aspects of global TB control, yet there is a lack of epidemiological evidence on the factors influencing adherence to TB drugs. Thus, this study aimed to explore the adherence and factors associated with adherence among TB patients in South Korea. Methods: We conducted a cohort study using a sampled national healthcare database from 2017 to 2018. Our study population included incident TB patients initiating quadruple or triple regimen who were available for follow-up for 180-days. Adherence was evaluated using the proportion of days covered (PDC): 1) adherent group: patients with PDC ≥80%; 2) non-adherent group: patients with PDC <80%. Kaplan-Meier analysis was conducted to calculate the median time-to-discontinuation in the study population. We calculated the adjusted odds ratios (aOR) with 95% confidence intervals (CI) to assess factors associated with adherence to TB drugs using logistic regression. Results: Of 987 patients, 558 (56.5%) were adherent and 429 (43.5%) were non-adherent, with the overall mean PDC of 68.87% (standard deviation, 33.37%). The median time-to-discontinuation was 113 days (interquartile range 96-136) in the study population. Patients initiating quadruple regimen were more likely to adhere in comparison to the triple regimen (aOR 4.14; 95% CI 2.78-6.17), while those aged ≥65 years (aOR 0.53; 95% CI 0.35-0.81), with a history of dementia (aOR 0.53; 95% CI 0.34-0.85), and with history of diabetes mellitus (aOR 0.70; 95% CI 0.52-0.96) were less likely to adhere to the drug. Conclusion: Approximately 45% of TB patients were non-adherent to the drug, which is a major concern for the treatment outcome. We call for intensified attention from the authorities and healthcare providers to reinforce patients' adherence to the prescribed TB drugs.

Comparative outcomes of lopinavir/ritonavir and hydroxychloroquine for the treatment of COVID-19 with mild-to-moderate severity: A retrospective observational study.

BACKGROUND: Lopinavir/ritonavir (LPV/r) and hydroxychloroquine (HCQ) are both being used to treat coronavirus disease 2019 (COVID-19), but their relative effectiveness is unknown. The purpose of this study was to compare the clinical outcomes of patients treated for COVID-19 with LPV/r or HCQ. METHODS: A retrospective observational study was conducted at 2 hospitals in Busan, South Korea, where approximately 90% of COVID-19 patients were hospitalised during February/March 2020. All patients aged ≥15 years that were hospitalised with mild or moderately severe COVID-19 received LPV/r or HCQ as their initial treatment and were included in the analysis. RESULTS: Among the 72 patients with mild-to-moderate disease severity on admission, 45 received LPV/r and 27 received HCQ as their initial therapy. A higher proportion of the LPV/r group had pneumonia on admission (LPV/r, 49% vs HCQ, 15%), but there were no other significant differences in the demographic or clinical characteristics between groups. Switching therapy due to clinical failure was significantly more common in the HCQ group than in the LPV/r group (41% [11/27] and 2% [1/45], respectively, P = .001). Disease progression was also significantly more common in the HCQ group than in the LPV/r group (44% [12/27] and 18% [8/45], respectively, P = .030). CONCLUSION: Based on our study results, HCQ shows no apparent advantage compared to LPV/r for preventing progression to severe disease in patients with COVID-19.

Complete response to radiation therapy for nasopharyngeal sarcomatoid carcinoma.

Nasopharyngeal sarcomatoid carcinoma (SaCa) is extremely rare, and concurrent chemoradiation is the standard treatment for squamous cell-based nasopharyngeal cancer (NPC). This case report gives the first explanation of a nasopharyngeal SaCa patient treated with volumetric modulated arc therapy (VMAT) with simultaneous integrated boost (SIB), which is an excellent treatment modality that leads to complete response for locally advanced NPC. A 70-year-old male presented with nasal obstruction, epistaxis, and right neck node enlargements. Examination revealed an extensive tumor of nasopharyngeal tumor extending into the nasal cavity and right parapharyngeal space with bilateral lymphadenopathy on positron emission tomography (PET)-computed tomography images of focal hypermetabolic bone lesion in C4 body (stage T3N2M1). An excisional biopsy of nasopharyngeal wall mass showed a SaCa. He received concurrent chemoradiation which was VMAT and systemic chemotherapy (cisplatin 60 mg). A dose of 70 Gy was delivered to the planning target volume (PTV70) (gross tumor volume plus margin 3-5 mm) and PTV59.4(a wider margin around high-risk clinical target volume, including the clivus and neck nodes) all given in 33 fractions. Radiological examination such as magnetic resonance imaging (MRI) and PET images at the completion of external beam therapy revealed questionable residual disease. Follow-up MRI scans 4 weeks after radiotherapy revealed a complete tumor response. VMAT with SIB can be an effective treatment option for SaCa of the advanced nasopharynx.