Attack Rate Research Articles

Investigating the epidemiology and outbreaks of scabies in Japanese households, residential care facilities, and hospitals using claims data: the Longevity Improvement & Fair Evidence (LIFE) study

ObjectivesThis study aimed to characterize the epidemiology of scabies and its outbreaks in Japanese households, residential care facilities (RCFs), and hospitals using claims data. MethodsThis descriptive epidemiological study was conducted using claims data from eight municipalities in Japan. Scabies cases were identified using a combination of recorded diagnoses and administered medications. The study period was from April 2015 to March 2019. Outbreaks were defined as ≥2 cases of scabies occurring within a calendar month at a single household, RCF, or hospital. ResultsWe identified 857 scabies cases for analysis. The annual prevalence of scabies ranged from 40 to 67 per 100,000 beneficiaries. The annual attack rate of scabies was found to be highest in RCFs (21 per 1000 RCFs), followed by hospitals (11 per 1000 hospitals) and households (0.25 per 1000 households). The annual outbreak attack rate was also highest in RCFs (4.0 per 1000 RCFs), followed by hospitals (1.6 per 1000 hospitals) and household (0.027 per household). The patterns of outbreaks varied widely among the RCFs. ConclusionsThe study showcases the potential of claims data for detecting infectious disease outbreaks, which could provide valuable insight for the future management and prevention of scabies. Infection control of scabies in RCFs is crucial in aging societies.

Comparing multiple infection control measures in a nursing home setting: a simulation study.

Compare the effectiveness of multiple mitigation measures designed to protect nursing home residents from infectious disease outbreaks. Agent-based simulation study. Simulation environment of a small nursing home. We collected temporally detailed and spatially fine-grained location information from nursing home healthcare workers (HCWs) using sensor motes. We used these data to power an agent-based simulation of a COVID-19 outbreak using realistic time-varying estimates of infectivity and diagnostic sensitivity. Under varying community prevalence and transmissibility, we compared the mitigating effects of (i) regular screening and isolation, (ii) inter-resident contact restrictions, (iii) reduced HCW presenteeism, and (iv) modified HCW scheduling. Across all configurations tested, screening every other day and isolating positive cases decreased the attack rate by an average of 27% to 0.501 on average, while contact restrictions decreased the attack rate by an average of 35%, resulting in an attack rate of only 0.240, approximately half that of screening/isolation. Combining both interventions impressively produced an attack rate of only 0.029. Halving the observed presenteeism rate led to an 18% decrease in the attack rate, but if combined with screening every 6 days, the effect of reducing presenteeism was negligible. Altering work schedules had negligible effects on the attack rate. Universal contact restrictions are highly effective for protecting vulnerable nursing home residents, yet adversely affect physical and mental health. In high transmission and/or high community prevalence situations, restricting inter-resident contact to groups of 4 was effective and made highly effective when paired with weekly testing.

The Effect of Several Types of Refugia Plants on Whitefly Populations and Production of Red Chili Varieties (Capsicum Annum L.)

The purpose of this study was to measure the effect of refugia on the whitefly population and the production of several varieties of red chili (Capsicum annum L.). This research was conducted in the experimental garden of the UTU Faculty of Agriculture, West Aceh Regency from March - June 2019. Materials used: TM 999 chili seeds, Lado F1 variety, F1 Lidia variety, NPK fertilizer, manure, Kenikir flower plants, Zinnia flowers, and polybags. Tools used: hoe, hand sprayer, camera, and stationery. This study used a 3x2 split plot design with 3 replications. The factor studied was the presence of a whitefly. As the main plot, Refugia (R) consists of three levels, namely R0 = Control, R1 = Zinnia, and R2 = Thinking. Variety (V) consists of 3 levels, namely V1 = TM 999, V2 = Lado F1, and V3 = Lidia F1. The variables observed were the calculation of whitefly population, the percentage of attack rate, and production per plot. The results showed that Refugia plants had a very significant effect on the whitefly population, percentage of pest attack rates, and production per plot. Variety has a significant effect on the percentage level of pest attacks and production per plot.

Parametric analysis of the transmission dynamics during indigenous aggregated outbreaks caused by five SARS-CoV-2 strains in Nanjing, China.

SARS-CoV-2 strains have been of great concern due to their high infectivity and antibody evasion. In this study, data were collected on indigenous aggregated outbreaks in Nanjing from January 2020 to December 2022, caused by five strains including the original strain, the Delta variant, and the Omicron variant (BA.2, BA.5.2, and BF.7). The basic epidemiological characteristics of infected individuals were described and then parametric analysis of transmission dynamics was performed, including the calculation of incubation period, serial interval (SI), the basic reproductive number (R0), and the household secondary attack rate (HSAR). Finally, we compared the trends of transmission dynamic parameters of different strains. The incubation period for the original strain, the Delta variant, Omicron BA.2, Omicron BA.5.2, and Omicron BF.7 were 6 d (95% CI: 3.5-7.5 d), 5 d (95% CI: 4.0-6.0 d), 3 d (95% CI: 3.0-4.0 d), 3 d (95% CI: 3.0-3.0 d), and 2 d (95% CI: 2.0-3.0 d), respectively; Also, the SI of the five strains were 5.69 d, 4.79 d, 2.7 d, 2.12 d, and 2.43 d, respectively. Notably, the incubation period and SI of the five had both a progressive shortening trend (p < 0.001); Moreover, R0 of the five were 2.39 (95% CI: 1.30-4.29), 3.73 (95% CI: 2.66-5.15), 5.28 (95% CI: 3.52-8.10), 5.54 (95% CI: 2.69-11.17), 7.39 (95% CI: 2.97-18.76), with an increasing trend gradually (p < 0.01); HSAR of the five were 25.5% (95% CI: 20.1-31.7%), 27.4% (95% CI: 22.0-33.4%), 42.9% (95% CI: 34.3-51.8%), 53.1% (95% CI: 45.0-60.9%), 41.4% (95% CI, 25.5-59.3%), also with an increasing trend (p < 0.001). Compared to the original strain, the incubation period and SI decreased while R0 and HSAR increased, suggesting that transmission in the population was faster and the scope of the population was wider. Overall, it's crucial to keep implementing comprehensive measures like monitoring and alert systems, herd immunization plans, and outbreak control.

The weekly P25 of the age of the influenza-like illness shows a higher correlation with COVID-19 mortality than rapid tests and could predict the evolution of COVID-19 pandemics in sentinel surveillance, Piura, Perú, 2021.

To describe the dynamics of syndromic surveillance of ILI cases in seasonal and COVID-19 pandemic scenarios. A descriptive study of the epidemiological behavior of ILI in the seasonal and COVID-19 pandemic scenarios. Of a sample of 16,231 cases of ILI from 2013 to 2021, the features of cases from 68 weeks before and during the pandemic were selected and compared; weekly endemic channels were built; data fluctuations on the trend of ILI cases were analyzed; and estimated weekly correlations between weekly P25 age, cases confirmed by rapid tests, and mortality from COVID-19. To analyze clinical-epidemiological and mortality data, Student's t test, Mann-Whitney U, Chi2, Spearman's Ro, polynomial, and multinomial regression with a 95% confidence interval were used. During the COVID-19 pandemic, those most affected with ILI were: adults and the elderly; higher median age; autochthonous cases predominated; a lower proportion of other syndromes; delays in seeking care; and a higher rate of pneumonia attack than in the seasonal period (p< 0.01). Rapid tests (serological and antigenic) confirmed 52.7% as COVID-19. Two ILI pandemic waves were seasonally consistent with confirmed COVID-19 cases and district mortality with robust correlation (p<0.01) before and during the pandemic, especially the ILI weekly P25 age, which has a more robust correlation with mortality than ILI and rapid tests (p<0.01) whose endemic channels describe and could predict the evolution of the pandemic (p<0.01). The pandemic changed the clinical and epidemiological behavior of ILI, and the weekly P25 of age is a more robust indicator to monitor the COVID-19 pandemic than a rapid test and could predict its evolution.

Modelling the unexpected dynamics of COVID-19 in Manaus, Brazil

In late March 2020, SARS-CoV-2 arrived in Manaus, Brazil, and rapidly developed into a large-scale epidemic that collapsed the local health system and resulted in extreme death rates. Several key studies reported that ∼76% of residents of Manaus were infected (attack rate AR≃76%) by October 2020, suggesting protective herd immunity had been reached. Despite this, an unexpected second wave of COVID-19 struck again in November and proved to be larger than the first, creating a catastrophe for the unprepared population. It has been suggested that this could be possible if the second wave was driven by reinfections. However, it is widely reported that reinfections were at a low rate (before the emergence of Omicron), and reinfections tend to be mild. Here, we use novel methods to model the epidemic from mortality data without considering reinfection-caused deaths and evaluate the impact of interventions to explain why the second wave appeared. The method fits a “flexible” reproductive number R0(t) that changes over the epidemic, and it is demonstrated that the method can successfully reconstruct R0(t) from simulated data. For Manaus, the method finds AR≃34% by October 2020 for the first wave, which is far less than required for herd immunity yet in-line with seroprevalence estimates. The work is complemented by a two-strain model. Using genomic data, the model estimates transmissibility of the new P.1 virus lineage as 1.9 times higher than that of the non-P.1. Moreover, an age class model variant that considers the high mortality rates of older adults show very similar results. These models thus provide a reasonable explanation for the two-wave dynamics in Manaus without the need to rely on large reinfection rates, which until now have only been found in negligible to moderate numbers in recent surveillance efforts.

Improving adversarial transferability through frequency enhanced momentum

The emergence of adversarial examples seriously affects the practical security deployment of convolutional neural networks. The existing attack algorithms perform brilliantly under white-box scenarios, but they show weak transferability when faced with unknown black-box models. Recent studies have revealed that models have different interests in different frequency components of images, and the low-frequency characteristics play a non-negligible role in the decision-making of models. In this article, we present the frequency enhanced momentum iterative attack, called FE-MI-FGSM. Specifically, we use multiple convolution kernels for Gaussian filtering of the image before each gradient update to push the processed image closer to the common decision boundaries of multiple models. Then, the average gradient of the white-box model to these processed images is obtained and used as the perturbation direction to generate adversarial examples with a high success rate of white-box attack and high transferability. The empirical results show that compared with the current mainstream gradient-based methods, our method performs better on both normally trained and adversarially trained models. Besides, our method can combine with gradient-based methods which integrate convergence algorithms or input transformations for the sake of reaching satisfactory improvement of the transferability.

Epidemiology and burden of respiratory syncytial virus in Italian adults: A systematic review and meta-analysis.

Respiratory syncytial virus (RSV) is a common respiratory pathogen not only in children, but also in adults. In view of a recent authorization of adult RSV vaccines in Italy, our research question was to quantify the epidemiology and burden of RSV in Italian adults. Observational studies on the epidemiology and clinical burden of laboratory-confirmed or record-coded RSV infection in Italian adults of any age were eligible. Studies with no separate data for Italian adults, modeling and other secondary publications were excluded. A literature search was performed in MEDLINE, Biological Abstracts, Global Health, Scopus and Web of Science on 22 November 2023. Critical appraisal was performed by means of a Joanna Briggs Institute checklist. Random-effects (RE) meta-analysis was performed to obtain pooled estimates and the observed heterogeneity was investigated by subgroup and meta-regression analyses. The protocol was prospectively registered (doi.org/10.17504/protocols.io.5qpvo32odv4o/v1). Thirty-five studies were identified, most of which had at least one possible quality concern. RSV seasonal attack rates ranged from 0.8 ‰ in community-dwelling older adults to 10.9% in hematological outpatients. In the RE model, 4.5% (95% CI: 3.2-5.9%) of respiratory samples tested positive for RSV. This positivity prevalence was higher in older adults (4.4%) than in working-age adults (3.5%) and in outpatient (4.9%) than inpatient (2.9%) settings. According to the meta-regression, study location and sample size were also significant predictors of RSV detection frequency. The pooled estimate of in-hospital mortality was as high as 7.2% (95% CI: 4.7-10.3%). Data on other indicators of the diseases burden, such as complication and hospitalization rates, were unavailable. RSV poses a measurable burden on Italian adults, especially those of older age and with some co-morbidities. However, several data on the natural history of RSV disease are missing and should be established by future large-scale studies.

Maxwell’s Demon in MLP-Mixer: towards transferable adversarial attacks

Models based on MLP-Mixer architecture are becoming popular, but they still suffer from adversarial examples. Although it has been shown that MLP-Mixer is more robust to adversarial attacks compared to convolutional neural networks (CNNs), there has been no research on adversarial attacks tailored to its architecture. In this paper, we fill this gap. We propose a dedicated attack framework called Maxwell’s demon Attack (MA). Specifically, we break the channel-mixing and token-mixing mechanisms of the MLP-Mixer by perturbing inputs of each Mixer layer to achieve high transferability. We demonstrate that disrupting the MLP-Mixer’s capture of the main information of images by masking its inputs can generate adversarial examples with cross-architectural transferability. Extensive evaluations show the effectiveness and superior performance of MA. Perturbations generated based on masked inputs obtain a higher success rate of black-box attacks than existing transfer attacks. Moreover, our approach can be easily combined with existing methods to improve the transferability both within MLP-Mixer based models and to models with different architectures. We achieve up to 55.9% attack performance improvement. Our work exploits the true generalization potential of the MLP-Mixer adversarial space and helps make it more robust for future deployments.

Characterization of the agonistic behavior of the weakly electric fish Gymnotus sylvius

AbstractElectric fish are good models in neuroethology as any behavior in electric fish involves both locomotor and electrical displays, which are experimentally accessible and controlled by well‐known neural circuits. The agonistic behavior within the genus Gymnotus has been evaluated in Gymnotus carapo and Gymnotus omarorum, providing an advantageous model system to address comparative analyses. Gymnotus sylvius is a weakly electric fish which occurs in sympatry with G. omarorum in freshwater environments of Argentina. Here, we describe the agonistic behavior of G. sylvius in laboratory conditions. All dyads engaged in intense fights, with a latency to the first attack of 8 ± 7.8 s and a contest phase of 42.71 ± 31.7 s. Individual initiative in the first attack predicted contest outcome with no apparent influence of body weight asymmetry between contenders. Contenders did not escalate in their aggression during the short contest; in turn, subordinates tended to retreat in response to dominants' attacks. Submission and dominance were expressed by electric signals: dominants increased their basal electric organ discharge (EOD) rate after contest resolution, resulting in a persistent EOD rate rank. Subordinates also emitted chirps and offs during the contest and post‐resolution phases without a clear temporal pattern. The agonistic behavior of G. sylvius presents some similarities with other species of the genus Gymnotus: EOD rank between dominants and subordinates, electric signals of submission, and the presence of attacks in the post‐resolution phase. On the other hand, it also presents differences: a shorter evaluation phase in G. sylvius, initiative as a determinant of outcome, a higher attack rate of dominants in G. sylvius, a different temporal pattern of chirps, and different mechanisms to separate EOD rate of dominants and subordinates. These facts open a promising road to analyze the evolution of different neuroendocrine strategies, operating on homologous neural pathways, to command the same behavior.

Deucrictibant for angioedema due to acquired C1-inhibitor deficiency: A randomized-controlled trial

BackgroundAngioedema due to acquired C1-inhibitor deficiency is a very rare but serious disease, with an estimated prevalence of 1 per 500,000 persons. There are no approved therapies to treat or prevent angioedema swellings in patients with this condition. Deucrictibant is a specific, orally bioavailable, competitive antagonist of the bradykinin B2 receptor currently under investigation for hereditary angioedema. ObjectiveTo assess the efficacy and safety of deucrictibant as acute and prophylactic treatment for angioedema due to acquired C1-inhibitor deficiency. MethodsA two-part, randomized, double-blind, placebo-controlled crossover study was conducted. In Part 1, four consecutive angioedema attacks were treated with three doses of deucrictibant (10 mg, 20 mg, and 30 mg) or placebo. In Part 2, deucricibant 20 mg or placebo was administered bidaily for two treatment periods of eight weeks. ResultsThree patients were enrolled of which one completed both study parts and two completed only Part 2. In Part 1, a reduction in attack severity was observed in the three attacks treated with deucrictibant as opposed to an increase in severity of the attack treated with placebo. In Part 2, the individual mean monthly attack rates were 2.0, 0.6 and 1.0 during the placebo period and 0.0 across all patients during treatment with deucrictibant. There were no severe adverse events, and one self-limiting treatment-emergent adverse event (abdominal pain). ConclusionsDeucrictibant has the potential to effectively and safely treat and prevent angioedema attacks due to acquired C1-inhibitor deficiency.

Epidemiology of COVID-19 outbreaks in aged care facilities during postvaccine period: a systematic review and meta-analysis

ObjectiveWe aimed to define the epidemiology of COVID-19 outbreaks in aged care facilities (ACFs) during the postvaccine period, including vaccine effectiveness (VE) for this high-risk group.DesignSystematic review and meta-analysis.Data sourcesOvid...

Functional response of Franklinothrips vespiformis (Thysanoptera: Aeolothripidae) to eggs and nymphs of Bemisia tabaci (Hemiptera: Aleyrodidae).

The Middle East Asia Minor 1 biotype of Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) is a greenhouse and field crop pest of global significance. The objective of this study was to assess the potential of the generalist predatory thrips, Franklinothrips vespiformis Crawford (Thysanoptera: Aeolothripidae), as a biological control agent for B. tabaci. This was achieved by determining the functional responses of F. vespiformis larvae and adults to the egg and nymphal stages of B. tabaci under laboratory conditions. Analyses consisted of 10 replicates of each predator and prey stage combination on bean leaf discs for a 24-h period. Following logistic regression analyses to determine the functional response type exhibited, response parameters were estimated with nonlinear least squares regression using Roger's equation. Results showed that F. vespiformis larvae and adults exhibited a Type II functional response when feeding on immature B. tabaci. The handling times (Th) of F. vespiformis larvae and adults were magnitudes higher for B. tabaci nymphs than they were for eggs, which were in part driven by the higher attack rates (a) observed on eggs. The maximum attack rate (T/Th) for B. tabaci eggs and nymphs exhibited by first-stage larvae, second-stage larvae, and adult F. vespiformis increased with increasing predator age. Results from this study suggest that F. vespiformis larvae and particularly adults are promising biological control agents for B. tabaci and are efficient predators at both low and high prey densities.

Recurrence of hypertriglyceridemia-associated acute pancreatitis: A multicenter, prospective cohort study

ObjectivesThere are scarce prospective data on recurrent hypertriglyceridemia-associated acute pancreatitis (HTG-AP). This study aimed to investigate the incidence, potential prognostic factors, and clinical relevance of recurrent HTG-AP. MethodsThis study is a multicenter, prospective cohort study. Adult patients with the first HTG-AP attack enrolled in the PERFORM registry between November 2020 and December 2021 were involved. All the study patients were followed up for more than two years with a two-round schedule. The Cox proportional-hazards model was applied to analyze the potential factors. Quality of life was evaluated using the EuroQol five-dimensional five-level health scale (EQ-5D-5L). ResultsA total of 184 patients from 25 sites were included in the study, and 161 patients completed the two-round follow-up. Among them, the mean follow-up time for the study patients was 31±4 months, and the incidence rate of recurrent HTG-AP attack was 23 % (37/161). All patients with recurrent episodes required readmission to the hospital. The EQ visual analog scale (VAS) score was significantly lower in patients with recurrent episodes compared to those without (76±10 vs. 82±12; P = 0.02) at the latest follow-up. Age <40 years old (hazard ratio [HR], 3.6; 95 % confidence interval [CI], 1.5–8.7; P = 0.004) and a history of diabetes (HR, 2.6; 95 %CI, 1.3–5.1; P = 0.005) were identified as potential predictor factors for recurrence. ConclusionsRecurrence of HTG-AP is common, especially for younger patients with diabetes. Recurrence necessitated additional hospital readmissions and was associated with compromised quality of life.

Candida auris outbreak at a tertiary care hospital during the COVID-19 pandemic

Candida auris (C auris) is a fungal pathogen that has the potential for environmental persistence leading to outbreaks in health care settings. There has been a worldwide surge in C auris outbreaks during the COVID-19 pandemic. In this report, we describe an outbreak of C auris, its control, patient outcomes, and lessons learned. The outbreak occurred in a 600-bed adult academic tertiary care hospital. Contact tracing was initiated immediately after identification of the index case and surveillance testing for C auris was obtained from patients who were exposed to the index case. Infection prevention measures were closely followed. A total of 560 cultures were performed on 453 unique patients between August 2021 and December 2021. Of those, 31 cultures (5.5%) were positive for C auris; 27 (87.1%) were colonized with C auris, while 4 patients developed a clinical infection (12.9%). The secondary attack rate was 6.8% (31/453). The 30-day all-cause mortality rate for all patients who tested positive for C auris was 9.7%. C auris can cause protracted outbreaks that result in colonization and invasive infections. Multidisciplinary work to improve adherence to infection prevention measures as well as targeted admission screening are essential to limit outbreaks.

Morphological Character and Clorophyl Content Index of Corn Infected with Dowry Disease on Land Applied With Slow Realease Fertilizer Based on Corn Cob Biochar

Downy mildew is a significant disease of corn plants caused by the pathogenic fungus Peronosclerospora maydis, with attack rates reaching 95%. The application of slow-release fertilizer based on corn cob biochar is expected to increase the resistance of corn plants. Similarly, Bacillus sp. and Pseudomonas sp. are known as antagonistic microorganisms. Bacteria can produce antibiotic compounds that hydrolyze fungal cell walls, siderophores, and other antibiotic properties that inhibit pathogen growth. This study aims to determine the morphological characteristics of downy mildew-infected corn on biochar-applied land. Treatments were arranged factorially in a Factorial Randomized Block Design repeated four times. The treatment was the application of slow-release fertilizer from biochar mixed with NPK fertilizer, namely control, slow-release fertilizer, slow-release fertilizer + cow urine, and slow-release fertilizer + cow urine + bacteria (Azobacter and Bacillus). The results showed that slow-release fertilizer gave the best growth to both normal and downy mildew-affected maize plants. The stomata of typical corn leaves were more open with regular vascular bundles, while those affected by downy mildew had more closed and irregular stomata. The chlorophyll content index in downy mildew-affected maize can also improve by applying biochar-based slow-release fertilizer.

Estimation of the infection attack rate of mumps in an outbreak among college students using paired serology

Mumps virus is a highly transmissible pathogen that is effectively controlled in countries with high vaccination coverage. Nevertheless, outbreaks have occurred worldwide over the past decades in vaccinated populations. Here we analyse an outbreak of mumps virus genotype G among college students in the Netherlands over the period 2009–2012 using paired serological data. To identify infections in the presence of preexisting antibodies we compared mumps specific serum IgG concentrations in two consecutive samples (n=746), whereby the first sample was taken when students started their study prior to the outbreaks, and the second sample was taken 2–5 years later. We fit a binary mixture model to the data. The two mixing distributions represent uninfected and infected classes. Throughout we assume that the infection probability increases with the ratio of antibody concentrations of the second to first sample. The estimated infection attack rate in this study is higher than reported earlier (0.095 versus 0.042). The analyses yield probabilistic classifications of participants, which are mostly quite precise owing to the high intraclass correlation of samples in uninfected participants (0.85, 95%CrI: 0.82−0.87). The estimated probability of infection increases with decreasing antibody concentration in the pre-outbreak sample, such that the probability of infection is 0.12 (95%CrI: 0.10−0.13) for the lowest quartile of the pre-outbreak samples and 0.056 (95%CrI: 0.044−0.068) for the highest quartile. We discuss the implications of these insights for the design of booster vaccination strategies.

Risk factors for SARS-CoV-2 transmission during a movie theater outbreak in Incheon in the Republic of Korea, November 2021: a retrospective study.

We examined factors contributing to the transmission of an acute respiratory virus within multi-use facilities, focusing on an outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a movie theater in the Republic of Korea. This retrospective cohort study involved a descriptive analysis of 48 confirmed cases. Logistic regression was applied to a cohort of 80 theater attendees to identify risk factors for infection. The infection source and transmission route were determined through gene sequencing data analysis. Of the 48 confirmed cases, 35 were theater attendees (72.9%), 10 were family members of attendees (20.8%), 2 were friends (4.2%), and 1 was an employee (2.1%). Among the 80 individuals who attended the 3rd to 5th screenings of the day, 35 became infected, representing a 43.8% attack rate. Specifically, 28 of the 33 third-screening attendees developed confirmed SARSCoV-2, constituting an 84.8% attack rate. Furthermore, 11 of the 12 cases epidemiologically linked to the theater outbreak were clustered monophyletically within the AY.69 lineage. At the time of the screening, 35 individuals (72.9%) had received 2 vaccine doses. However, vaccination status did not significantly influence infection risk. Multivariate analysis revealed that close contacts had a 15.9-fold higher risk of infection (95% confidence interval, 4.37-78.39) than casual contacts. SARS-CoV-2 transmission occurred within the theater, and extended into the community, via a moviegoer who attended the 3rd screening during the viral incubation period after contracting the virus from a family member. This study emphasizes the importance of adequate ventilation in theaters.

Disease burden attributable to respiratory syncytial virus outbreaks in long-term care.

Respiratory syncytial virus (RSV) disease burden is significant among children; however, RSV can also cause excess morbidity and mortality among older adults. Populations in long-term care homes (LTCHs) may be at greater risk of exposure and increased infection severity. The objectives of this article are to identify evidence regarding disease burden and outcome severity attributable to RSV outbreaks among residents and staff in LTCHs; and to highlight reported population and outbreak characteristics. All types of evidence were eligible for inclusion. Data utilized by included studies was between the end of the 2010 H1N1 influenza pandemic and the beginning of the coronavirus disease 2019 (COVID-19) pandemic. Evidence from the following countries was considered: G7, the European Union, Australia and New Zealand. A total of 167 articles were identified; 58 full texts were analyzed and four sources of evidence were eligible for inclusion. Data related to population characteristics, outbreak type and resident and staff outcomes were manually charted. There is a paucity of evidence sources pertaining to RSV outbreak burden among residents and staff in LTCHs. Outbreak duration ranged from 13 to 21 days. For each outbreak, 4-7 residents had confirmed RSV infection. Attack rates ranged from 12% to 38%. A spectrum of disease attributable to RSV outbreaks in LTCHs was identified, ranging from mild cold-like symptoms to death. Integration of RSV into existing respiratory pathogen surveillance programs is important to characterize susceptibility, transmissibility and virulence of RSV in at-risk populations. There is a need for public health organizations to publish the findings from outbreak investigations to provide evidence to inform RSV outbreak prevention and response in LTCH settings.

Characteristics of a large outbreak arising from a school field trip after COVID-19 restrictions were eased in 2022.

This study analyzed a large outbreak of coronavirus disease 2019 (COVID-19) that occurred during a high school field trip in the Jeonbuk region and aimed to identify risk factors for COVID-19 infection, with the goal of preventing such outbreaks in the future. A retrospective cohort study of 737 participants, including 668 students and 69 staff at High School A, was designed to describe the epidemiological characteristics of this large COVID-19 outbreak. Logistic regression analysis was performed to calculate relative risks (odds ratios [ORs]) and 95% confidence intervals (CIs). There were 190 confirmed cases (174 students, 16 staff), with an attack rate of 25.8%. Small outbreaks were decreasing before the field trip, but this trend reversed after the trip, leading to larger outbreaks. Logistic regression showed an OR of 2.39 (95% CI, 1.66-3.43; p<0.05) for COVID-19 infection among field trip participants. Among them, 11th graders had an OR of 2.32 (95% CI, 1.53-3.52; p<0.05) compared to 10th graders, while no significant risk difference was found within same-grade teams. There was a high risk for COVID-19 transmission during extracurricular activities with a large number of participants, such as field trips, even after the nationwide Omicron variant epidemic subsided. Even when students are separated into teams and follow different routes, it is challenging to design routes that entirely prevent contact between teams. Thus, programs should be designed carefully, and students with symptoms should be identified before and during the program to isolate them promptly.