Age-related model for estimating the symptomatic and asymptomatic transmissibility of COVID-19 patients.

Estimation of age-dependent transmissibility of COVID-19 patients is critical for effective policymaking. Although the transmissibility of symptomatic cases has been extensively studied, asymptomatic infection is understudied due to limited data. Using a dataset with reliably distinguished symptomatic and asymptomatic statuses of COVID-19 cases, we propose an ordinary differential equation model that considers age-dependent transmissibility in transmission dynamics. Under a Bayesian framework, multi-source information is synthesized in our model for identifying transmissibility. A shrinkage prior among age groups is also adopted to improve the estimation behavior of transmissibility from age-structured data. The added values of accounting for age-dependent transmissibility are further evaluated through simulation studies. In real-data analysis, we compare our approach with two basic models using the deviance information criterion (DIC) and its extension. We find that the proposed model is more flexible for our epidemic data. Our results also suggest that the transmissibility of asymptomatic infections is significantly lower (on average, 76.45% with a credible interval (27.38%, 88.65%)) than that of symptomatic cases. In both symptomatic and asymptomatic patients, the transmissibility mainly increases with age. Patients older than 30 years are more likely to develop symptoms with higher transmissibility. We also find that the transmission burden of asymptomatic cases is lower than that of symptomatic patients.

Transmission roles of symptomatic and asymptomatic COVID-19 cases: a modelling study.

Coronavirus disease 2019 (COVID-19) asymptomatic cases are hard to identify, impeding transmissibility estimation. The value of COVID-19 transmissibility is worth further elucidation for key assumptions in further modelling studies. Through a population-based surveillance network, we collected data on 1342 confirmed cases with a 90-days follow-up for all asymptomatic cases. An age-stratified compartmental model containing contact information was built to estimate the transmissibility of symptomatic and asymptomatic COVID-19 cases. The difference in transmissibility of a symptomatic and asymptomatic case depended on age and was most distinct for the middle-age groups. The asymptomatic cases had a 66.7% lower transmissibility rate than symptomatic cases, and 74.1% (95% CI 65.9-80.7) of all asymptomatic cases were missed in detection. The average proportion of asymptomatic cases was 28.2% (95% CI 23.0-34.6). Simulation demonstrated that the burden of asymptomatic transmission increased as the epidemic continued and could potentially dominate total transmission. The transmissibility of asymptomatic COVID-19 cases is high and asymptomatic COVID-19 cases play a significant role in outbreaks.

Role of country image, subjective knowledge, and destination trust on travel attitude and intention during a pandemic

This study set out to investigate the effects of country image (CI), subjective knowledge (SK) of COVID-19, and destination trust (DT) and their relationship to travel attitude and visit intention during the COVID-19 pandemic. This research used Canada and the USA as cases to investigate people's domestic and international travel intentions. It tested the travel attitude and visit intention of domestic residents and international travellers, specifically Canadians travelling domestically versus Americans travelling domestically, and Canadians travelling to the USA versus Americans travelling to Canada. Two timeframes (i.e., one year vs. two years) were examined to further reveal the underlying relationships between those important constructs. First, this study supports findings that CI positively influences travel attitude and that DT is more prominent compared to CI under the adverse conditions of an ongoing pandemic. The indirect impact of CI through DT on travel attitude is significantly greater than the direct impact of CI. Second, it confirms that SK of COVID-19 negatively influences both domestic and international travel attitude. However, the impact of SK on DT varies with the risk of the domestic environment. Third, there were no direct impacts of CI, SK, and DT on domestic visit intention.

Two-Year Health Outcomes in Hospitalized COVID-19 Survivors in China.

Importance: Relatively little is known about the persistence of symptoms in patients with COVID-19 for more than 1 year after their acute illness. Objective: To assess the health outcomes among hospitalized COVID-19 survivors over 2 years and to identify factors associated with increased risk of persistent symptoms. Design, Setting, and Participants: This was a longitudinal cohort study of patients who survived COVID-19 at 2 COVID-19-designated hospitals in Wuhan, China, from February 12 to April 10, 2020. All patients were interviewed via telephone at 1 year and 2 years after discharge. The 2-year follow-up study was conducted from March 1 to April 6, 2022. Statistical analysis was conducted from April 20 to May 5, 2022. The severity of disease was defined by World Health Organization guideline for COVID-19. Exposures: COVID-19. Main Outcomes and Measures: The main outcome was symptom changes over 2 years after hospital discharge. All patients completed a symptom questionnaire for evaluation of symptoms, along with a chronic obstructive pulmonary disease assessment test (CAT) at 1-year and 2-year follow-up visits. Results: Of 3988 COVID-19 survivors, a total of 1864 patients (median [IQR] age, 58.5 [49.0-68.0] years; 926 male patients [49.7%]) were available for both 1-year and 2-year follow-up visits. The median (IQR) time from discharge to follow-up at 2 years was 730 (719-743) days. At 2 years after hospital discharge, 370 patients (19.8%) still had symptoms, including 224 (12.0%) with persisting symptoms and 146 (7.8%) with new-onset or worsening of symptoms. The most common symptoms were fatigue, chest tightness, anxiety, dyspnea, and myalgia. Most symptoms resolved over time, but the incidence of dyspnea showed no significant change (1-year vs 2-year, 2.6% [49 patients] vs 2.0% [37 patients]). A total of 116 patients (6.2%) had CAT total scores of at least 10 at 2 years after discharge. Patients who had been admitted to the intensive care unit had higher risks of persistent symptoms (odds ratio, 2.69; 95% CI, 1.02-7.06; P = .04) and CAT scores of 10 or higher (odds ratio, 2.83; 95% CI, 1.21-6.66; P = .02). Conclusions and Relevance: In this cohort study, 2 years after hospital discharge, COVID-19 survivors had a progressive decrease in their symptom burden, but those with severe disease during hospitalization, especially those who required intensive care unit admission, had higher risks of persistent symptoms. These results are related to the original strain of the virus, and their relevance to infections with the Omicron variant is not known.

Costs, Reach, and Benefits of COVID-19 Pandemic Electronic Benefit Transfer and Grab-and-Go School Meals for Ensuring Youths' Access to Food During School Closures.

Importance: School meals are associated with improved nutrition and health for millions of US children, but school closures due to the COVID-19 pandemic disrupted children's access to school meals. Two policy approaches, the Pandemic Electronic Benefit Transfer (P-EBT) program, which provided the cash value of missed meals directly to families on debit-like cards to use for making food purchases, and the grab-and-go meals program, which offered prepared meals from school kitchens at community distribution points, were activated to replace missed meals for children from low-income families; however, the extent to which these programs reached those who needed them and the programs' costs were unknown. Objective: To assess the proportion of eligible youths who were reached by P-EBT and grab-and-go meals, the amount of meals or benefits received, and the cost to implement each program. Design, Setting, and Participants: This cross-sectional study was conducted from March to June 2020. The study population was all US youths younger than 19 years, including US youths aged 6 to 18 years who were eligible to receive free or reduced-price meals (primary analysis sample). Exposures: Receipt of P-EBT or grab-and-go school meals. Main Outcomes and Measures: The main outcomes were the percentage of youths reached by P-EBT and grab-and-go school meals, mean benefit received per recipient, and mean cost, including implementation costs and time costs to families per meal distributed. Results: Among 30 million youths eligible for free or reduced-price meals, grab-and-go meals reached an estimated 8.0 million (27%) and P-EBT reached 26.9 million (89%). The grab-and-go school meals program distributed 429 million meals per month in spring 2020, and the P-EBT program distributed $3.2 billion in monthly cash benefits, equivalent to 1.1 billion meals. Among those receiving benefits, the mean monthly benefit was larger for grab-and-go school meals ($148; range across states, $44-$176) compared with P-EBT ($110; range across states, $55-$114). Costs per meal delivered were lower for P-EBT ($6.46; range across states, $6.41-$6.79) compared with grab-and-go school meals ($8.07; range across states, $2.97-$15.27). The P-EBT program had lower public sector implementation costs but higher uncompensated time costs to families (eg, preparation time for meals) compared with grab-and-go school meals. Conclusions and Relevance: In this economic evaluation, both the P-EBT and grab-and-go school meal programs supported youths' access to food in complementary ways when US schools were closed during the COVID-19 pandemic from March to June 2020.

Book review

Chapter 10 reviews the crises and disasters that influence world tourism cities and introduces crisis management approaches, such as the crisis signal detection framework and social-mediated crisis communication model. [...]this book is highly recommended for students in the tourism management major. Furthermore, each chapter makes effective use of tables and figures to demonstrate differences in related concepts, such as the seven steps of the tourism planning process, seventeen potential tourism developments and themes for city destinations, and the 10 As model for city tourism development factors.

High Prevalence of Both Previous Infection with SARS-CoV-2 and Persistent Symptoms.

INTRODUCTION: Universities are unique settings with large populations, congregate housing, and frequent attendance of events in large groups. However, the current prevalence of previous COVID-19 infection in university students, including symptomatic and asymptomatic disease, is unknown. Our goal therefore was to determine the prevalence of previous infection, risk factors for infection, and the prevalence of persistent symptoms following infection among university students. METHODS: This was a cross-sectional study set in a large public university between January 22 and March 22, 2021. We surveyed students about demographics, risk factors, and symptoms, and simultaneously tested their saliva for IgA antibodies to SARS-CoV-2. To estimate the prevalence of previous infection we adjusted our intentional sample of a diverse student population for year in school and age to resemble the composition of the entire student body and adjusted for the imperfect sensitivity and specificity of the antibody test. Univariate and multiple regression analysis was used to identify independent risk factors for infection, and the proportion of students with persistent symptoms following acute infection was determined. RESULTS: A total of 488 students completed the survey, 432 had a valid antibody result, and 428 had both. The estimated prevalence of previous infection for 432 participants with valid antibody results was 41%. Of 145 students in our sample with a positive antibody test, 41.4% denied having a previous positive polymerase chain reaction (PCR) test for SARS-CoV-2 and presumably had an asymptomatic infection; in our adjusted analysis we estimate that approximately 2-thirds of students had asymptomatic infections. Independent risk factors for infection included male sex, having a roommate with a known symptomatic infection, and having two or fewer roommates. More frequent attendance of parties and bars was a univariate risk factor, but not in the multiple regression analysis. Of 122 students reporting a previous symptomatic infection, 14 (11.4%) reported persistent symptoms consistent with postacute COVID-19 a median of 132 days later. CONCLUSIONS AND RELEVANCE: Previous COVID-19 infection, both symptomatic and asymptomatic, was common at a large university. Measures that could prevent resurgence of the infection when students return to campus include mandatory vaccination policies, mass surveillance testing, and testing of sewage for antigen to SARS-CoV-2.

Development and Validation of a Two-Step Predictive Risk Stratification Model for Coronavirus Disease 2019 In-hospital Mortality: A Multicenter Retrospective Cohort Study.

Objectives: An accurate prognostic score to predict mortality for adults with COVID-19 infection is needed to understand who would benefit most from hospitalizations and more intensive support and care. We aimed to develop and validate a two-step score system for patient triage, and to identify patients at a relatively low level of mortality risk using easy-to-collect individual information. Design: Multicenter retrospective observational cohort study. Setting: Four health centers from Virginia Commonwealth University, Georgetown University, the University of Florida, and the University of California, Los Angeles. Patients: Coronavirus Disease 2019-confirmed and hospitalized adult patients. Measurements and Main Results: We included 1,673 participants from Virginia Commonwealth University (VCU) as the derivation cohort. Risk factors for in-hospital death were identified using a multivariable logistic model with variable selection procedures after repeated missing data imputation. A two-step risk score was developed to identify patients at lower, moderate, and higher mortality risk. The first step selected increasing age, more than one pre-existing comorbidities, heart rate >100 beats/min, respiratory rate ≥30 breaths/min, and SpO2 <93% into the predictive model. Besides age and SpO2, the second step used blood urea nitrogen, absolute neutrophil count, C-reactive protein, platelet count, and neutrophil-to-lymphocyte ratio as predictors. C-statistics reflected very good discrimination with internal validation at VCU (0.83, 95% CI 0.79-0.88) and external validation at the other three health systems (range, 0.79-0.85). A one-step model was also derived for comparison. Overall, the two-step risk score had better performance than the one-step score. Conclusions: The two-step scoring system used widely available, point-of-care data for triage of COVID-19 patients and is a potentially time- and cost-saving tool in practice.

Symptoms and Health Outcomes Among Survivors of COVID-19 Infection 1 Year After Discharge From Hospitals in Wuhan, China.

Importance: The long-term health outcomes and symptom burden of COVID-19 remain largely unclear. Objective: To evaluate health outcomes of COVID-19 survivors 1 year after hospital discharge and to identify associated risk factors. Design, Setting, and Participants: This retrospective, multicenter cohort study was conducted at 2 designated hospitals, Huoshenshan Hospital and Taikang Tongji Hospital, both in Wuhan, China. All adult patients with COVID-19 discharged between February 12 and April 10, 2020, were screened for eligibility. Of a consecutive sample of 3988 discharged patients, 1555 were excluded (796 declined to participate and 759 were unable to be contacted) and the remaining 2433 patients were enrolled. All patients were interviewed via telephone from March 1 to March 20, 2021. Statistical analysis was performed from March 28 to April 18, 2021. Exposures: COVID-19. Main Outcomes and Measures: All patients participated in telephone interviews using a series of questionnaires for evaluation of symptoms, along with a chronic obstructive pulmonary disease (COPD) assessment test (CAT). Logistic regression models were used to evaluate risk factors for fatigue, dyspnea, symptom burden, or higher CAT scores. Results: Of 2433 patients at 1-year follow-up, 1205 (49.5%) were men and 680 (27.9%) were categorized into the severe disease group as defined by the World Health Organization guideline; the median (IQR) age was 60.0 (49.0-68.0) years. In total, 1095 patients (45.0%) reported at least 1 symptom. The most common symptoms included fatigue, sweating, chest tightness, anxiety, and myalgia. Older age (odds ratio [OR], 1.02; 95% CI, 1.01-1.02; P < .001), female sex (OR, 1.27; 95% CI, 1.06-1.52; P = .008), and severe disease during hospital stay (OR, 1.43; 95% CI, 1.18-1.74; P < .001) were associated with higher risks of fatigue. Older age (OR, 1.02; 95% CI, 1.01-1.03; P < .001) and severe disease (OR, 1.51; 95% CI, 1.14-1.99; P = .004) were associated with higher risks of having at least 3 symptoms. The median (IQR) CAT score was 2 (0-4), and a total of 161 patients (6.6%) had a CAT score of at least 10. Severe disease (OR, 1.84; 95% CI, 1.31-2.58; P < .001) and coexisting cerebrovascular diseases (OR, 1.95; 95% CI, 1.07-3.54; P = .03) were independent risk factors for CAT scores of at least 10. Conclusions and Relevance: This study found that patients with COVID-19 with severe disease during hospitalization had more postinfection symptoms and higher CAT scores.

Critical Role of Simultaneous Reduction of Atmospheric Odd Oxygen for Winter Haze Mitigation.

The lockdown due to COVID-19 created a rare opportunity to examine the nonlinear responses of secondary aerosols, which are formed through atmospheric oxidation of gaseous precursors, to intensive precursor emission reductions. Based on unique observational data sets from six supersites in eastern China during 2019-2021, we found that the lockdown caused considerable decreases (32-61%) in different secondary aerosol components in the study region because of similar-degree precursor reductions. However, due to insufficient combustion-related volatile organic compound (VOC) reduction, odd oxygen (Ox = O3 + NO2) concentration, an indicator of the extent of photochemical processing, showed little change and did not promote more decreases in secondary aerosols. We also found that the Chinese provinces and international cities that experienced reduced Ox during the lockdown usually gained a greater simultaneous PM2.5 decrease than other provinces and cities with an increased Ox. Therefore, we argue that strict VOC control in winter, which has been largely ignored so far, is critical in future policies to mitigate winter haze more efficiently by reducing Ox simultaneously.

COVID-19 Transmission Dynamics Among Close Contacts of Index Patients With COVID-19: A Population-Based Cohort Study in Zhejiang Province, China.

Importance: Much remains unknown about the transmission dynamics of COVID-19. How the severity of the index case and timing of exposure is associated with disease in close contacts of index patients with COVID-19 and clinical presentation in those developing disease is not well elucidated. Objectives: To investigate the association between the timing of exposure and development of disease among close contacts of index patients with COVID-19 and to evaluate whether the severity of the index case is associated with clinical presentation in close contacts who develop COVID-19. Design, Setting, and Participants: This study used a large, population-based cohort of 730 individuals (index patients) who received a diagnosis of COVID-19 in Zhejiang Province, China, from January 8 to July 30, 2020, along with a contact tracing surveillance program. Field workers visited 8852 close contacts of the index patients and evaluated them for COVID-19 through August 2020. A timeline was constructed to characterize different exposure periods between index patients and their contacts. Main Outcomes and Measures: The primary outcome was the attack rate of COVID-19, defined as the total number of new COVID-19 cases diagnosed among contacts of index patients divided by the total number of exposed contacts. A secondary outcome was asymptomatic clinical presentation among infected contacts. Relative risks were calculated to investigate risk factors for COVID-19 among contacts and asymptomatic clinical presentation among infected contacts. Results: Among 8852 close contacts (4679 male contacts [52.9%]; median age, 41 years [interquartile range, 28-54 years]) of 730 index patients (374 male patients [51.2%]; median age, 46 years [interquartile range, 36-56 years]), contacts were at highest risk of COVID-19 if they were exposed between 2 days before and 3 days after the index patient's symptom onset, peaking at day 0 (adjusted relative risk [ARR], 1.3; 95% CI, 1.2-1.5). Compared with being exposed to an asymptomatic index patient, the risk of COVID-19 among contacts was higher when they were exposed to index patients with mild (ARR, 4.0; 95% CI, 1.8-9.1) and moderate (ARR, 4.3; 95% CI, 1.9-9.7) cases of COVID-19. As index case severity increased, infected contacts were less likely to be asymptomatic (exposed to patient with mild COVID-19: ARR, 0.3; 95% CI, 0.1-0.9; exposed to patient with moderate COVID-19: ARR, 0.3; 95% CI, 0.1-0.8). Conclusions and Relevance: This cohort study found that individuals with COVID-19 were most infectious a few days before and after symptom onset. Infected contacts of asymptomatic index patients were less likely to present with COVID-19 symptoms, suggesting that quantity of exposure may be associated with clinical presentation in close contacts.

Feeding Children and Maintaining Food Service Operations during COVID-19: A Mixed Methods Investigation of Implementation and Financial Challenges.

The United States Department of Agriculture (USDA) National School Lunch and Breakfast Programs are critical for the health and food security of U.S. schoolchildren, but access to these programs was disrupted by COVID-19 pandemic-related school closures in spring 2020. While temporary policy changes to the programs enabled school food authorities (SFAs) to pivot towards distributing meals throughout their communities instead of within school buildings, SFAs faced complex challenges during COVID-19 with minimal external support. This mixed methods study investigates the implementation and financial challenges experienced by twelve of the largest urban SFAs in the U.S. during COVID-19. We conducted semi-structured interviews with SFA leaders and analyzed alongside quantitative financial data. We found that SFAs reconfigured their usual operations with nearly no preparation time while simultaneously trying to keep staff from contracting COVID-19, accommodate stakeholders with sometimes competing priorities, and remain financially solvent. Because student participation was much lower than during regular times, and revenue is tied to the number of meals served, SFAs saw drastic decreases in revenue even as they carried regular operating costs. For future crises, disaster preparedness plans that help SFAs better navigate the switch to financially viable community distribution methods are needed.

Collateral Impact of the Coronavirus Disease 2019 (COVID-19) Pandemic on Tuberculosis Control in Jiangsu Province, China.

The coronavirus disease 2019 (COVID-19) pandemic may impede global tuberculosis elimination goals. In Jiangsu Province, China, tuberculosis notifications dropped 52% in 2020 compared to 2015-2019. Treatment completion and screening for drug resistance decreased continuously in 2020. Urgent attention must be paid to tuberculosis control efforts during and after the COVID-19 pandemic.

The impact of social distancing, contact tracing, and case isolation interventions to suppress the COVID-19 epidemic: A modeling study.

INTRODUCTION: Most countries are dependent on nonpharmaceutical public health interventions such as social distancing, contact tracing, and case isolation to mitigate COVID-19 spread until medicines or vaccines widely available. Minimal research has been performed on the independent and combined impact of each of these interventions based on empirical case data. METHODS: We obtained data from all confirmed COVID-19 cases from January 7th to February 22nd 2020 in Zhejiang Province, China, to fit an age-stratified compartmental model using human contact information before and during the outbreak. The effectiveness of social distancing, contact tracing, and case isolation was studied and compared in simulation. We also simulated a two-phase reopening scenario to assess whether various strategies combining nonpharmaceutical interventions are likely to achieve population-level control of a second-wave epidemic. RESULTS: Our study sample included 1,218 symptomatic cases with COVID-19, of which 664 had no inter-province travel history. Results suggest that 36.5 % (95 % CI, 12.8-57.1) of contacts were quarantined, and approximately five days (95 % CI, 2.2-11.0) were needed to detect and isolate a case. As contact networks would increase after societal and economic reopening, avoiding a second wave without strengthening nonpharmaceutical interventions compared to the first wave it would be exceedingly difficult. CONCLUSIONS: Continuous attention and further improvement of nonpharmaceutical interventions are needed in second-wave prevention. Specifically, contact tracing merits further attention.

Estimation of case-fatality rate in COVID-19 patients with hypertension and diabetes mellitus in the New York state: a preliminary report.

Pre-existing health conditions may exacerbate the severity of coronavirus disease 2019 (COVID-19). We aimed to estimate the case-fatality rate (CFR) and rate ratios (RR) for patients with hypertension (HBP) and diabetes mellitus (DM) in the New York state. We obtained the age-specific number of COVID-19 confirmed cases and deaths from public reports provided by the New York State Department of Health, and age-specific prevalence of HBP and DM from the Behavioral Risk Factor Surveillance System 2017. We calculated CFR and RR for COVID-19 patients with HBP and DM based on the reported number of deaths with the comorbidity divided by the expected number of COVID-19 cases with the comorbidity. We performed subgroup analysis by age and calculated the CFR and RR for ages of 18-44, 45-64 and 65+ years, respectively. We found that the older population had a higher CFR, but the elevated RRs associated with comorbidities are more pronounced among the younger population. Our findings suggest that besides the elderly, the young population with comorbidity should also be considered as a vulnerable group.

Investigation of dry eye symptoms of medical staffs working in hospital during 2019 novel coronavirus outbreak.

The aim of this study was to survey the prevalence of dry eye symptoms (DES) among doctors and nurses in the period of 2019, novel coronavirus (COVID-19) outbreak.To evaluate the DES of doctors and nurses worked at front-line hospitals with protective glasses for a mean time of 4 to 6 hours, a questionnaire developed by the researchers with the Ocular Surface Disease Index (OSDI) was used. These data were evaluated using descriptive statistics and correlation test with SPSS 22.0.The study included 13 doctors and 40 nurses, among which 16 were male and 37 were female, and the mean age of the participants was 32.43 ±â€Š5.15 years old. According to the OSDI scores, 64.15, 24.52, 7.54, and 3.77% of the participants experienced occasional, mild, moderate, and severe DES, respectively. The factors significantly correlated with OSDI scores were age and duration of wearing protective glasses, while the duration of wearing protective glasses may be a protective factor of dry eye symptoms.Our study showed that most of the doctors and nurses worked at the front-line of combating COVID-19 did not experience DES, while the symptoms of those who experienced DES might be improved by wearing protective glasses.

Community Outbreak Investigation of SARS-CoV-2 Transmission Among Bus Riders in Eastern China.

Importance: Evidence of whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19), can be transmitted as an aerosol (ie, airborne) has substantial public health implications. Objective: To investigate potential transmission routes of SARS-CoV-2 infection with epidemiologic evidence from a COVID-19 outbreak. Design, Setting, and Participants: This cohort study examined a community COVID-19 outbreak in Zhejiang province. On January 19, 2020, 128 individuals took 2 buses (60 [46.9%] from bus 1 and 68 [53.1%] from bus 2) on a 100-minute round trip to attend a 150-minute worship event. The source patient was a passenger on bus 2. We compared risks of SARS-CoV-2 infection among at-risk individuals taking bus 1 (n = 60) and bus 2 (n = 67 [source patient excluded]) and among all other individuals (n = 172) attending the worship event. We also divided seats on the exposed bus into high-risk and low-risk zones according to the distance from the source patient and compared COVID-19 risks in each zone. In both buses, central air conditioners were in indoor recirculation mode. Main Outcomes and Measures: SARS-CoV-2 infection was confirmed by reverse transcription polymerase chain reaction or by viral genome sequencing results. Attack rates for SARS-CoV-2 infection were calculated for different groups, and the spatial distribution of individuals who developed infection on bus 2 was obtained. Results: Of the 128 participants, 15 (11.7%) were men, 113 (88.3%) were women, and the mean age was 58.6 years. On bus 2, 24 of the 68 individuals (35.3% [including the index patient]) received a diagnosis of COVID-19 after the event. Meanwhile, none of the 60 individuals in bus 1 were infected. Among the other 172 individuals at the worship event, 7 (4.1%) subsequently received a COVID-19 diagnosis. Individuals in bus 2 had a 34.3% (95% CI, 24.1%-46.3%) higher risk of getting COVID-19 compared with those in bus 1 and were 11.4 (95% CI, 5.1-25.4) times more likely to have COVID-19 compared with all other individuals attending the worship event. Within bus 2, individuals in high-risk zones had moderately, but nonsignificantly, higher risk for COVID-19 compared with those in the low-risk zones. The absence of a significantly increased risk in the part of the bus closer to the index case suggested that airborne spread of the virus may at least partially explain the markedly high attack rate observed. Conclusions and Relevance: In this cohort study and case investigation of a community outbreak of COVID-19 in Zhejiang province, individuals who rode a bus to a worship event with a patient with COVID-19 had a higher risk of SARS-CoV-2 infection than individuals who rode another bus to the same event. Airborne spread of SARS-CoV-2 seems likely to have contributed to the high attack rate in the exposed bus. Future efforts at prevention and control must consider the potential for airborne spread of the virus.

Relapsing viral keratoconjunctivitis in COVID-19: a case report.

BACKGROUND: Since the outbreak of Coronavirus Disease 2019 (COVID-19) in December 2019, many studies have reported the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the conjunctival sac of patients infected with this virus, with several patients displaying symptoms of viral conjunctivitis. However, to our best knowledge, there is no in-depth report on the course of patients with COVID-19 complicated by relapsing viral conjunctivitis or keratoconjunctivitis. CASE PRESENTATION: A 53-year-old man confirmed with COVID-19 developed symptoms of viral conjunctivitis in the left eye approximately 10 days after the onset of COVID-19. The results of a nucleic acid test were positive for SARS-CoV-2 in the conjunctival sac of the left eye. The symptoms were relieved 6 days after treatment. However, the patient was subsequently diagnosed with viral keratoconjunctivitis in both eyes 5 days after the symptoms in the left eye were satisfactorily relieved. The disease progressed rapidly, with spot staining observed at the periphery of the corneal epithelium. Although SARS-CoV-2 could not be detected in conjunctival secretions, the levels of inflammatory factors, such as interleukin-6, were increased in both eyes. Both eyes were treated with glucocorticoids, and symptoms were controlled within 5 days. There was no recurrence. CONCLUSIONS: In this case report, the pathogenesis, clinical manifestations, treatment, and outcome of a case with COVID-19 complicated by relapsing viral keratoconjunctivitis is described, and the involvement of topical cytokine surge in the pathogenesis of COVID-19 as it relates to viral keratoconjunctivitis is reported.