RESUMO
SARS-CoV-2 is the etiological agent responsible for the COVID-19 pandemic. It is estimated that only 10 aerosol-borne virus particles are sufficient to establish a secondary infection with SARS-CoV-2. However, the dispersal pattern of SARS-CoV-2 is highly variable and only 10- 20% of cases are responsible for up 80% of secondary infections. The heterogeneous nature of SARS-CoV-2 transmission suggests that super-spreader events play an important role in viral transmission. Super-spreader events occur when a single person is responsible for an unusually high number of secondary infections due to a combination of biological, environmental, and/or behavioral factors. While super-spreader events have been identified as a significant factor driving SARS-CoV-2 transmission, epidemiologic studies have consistently shown that education settings do not play a major role in community transmission. However, an outbreak of SARS-CoV-2 was recently reported among 186 children (aged 10-17) and adults (aged 18 +) after attending an overnight summer camp in Texas in June 2021. To understand the transmission dynamics of the outbreak, RNA was isolated from 36 nasopharyngeal swabs collected from patients that attended the camp and 19 control patients with no known connection to the outbreak. Genome sequencing on the Oxford Nanopore platform was performed using the ARTIC approaches for library preparation and bioinformatic analysis. SARS-CoV-2 amplicons were produced from all RNA samples and >70% of the viral genome was successfully reconstructed with >10X coverage for 46 samples. Phylogenetic methods were used to estimate the transmission history and suggested that the outbreak was the result of a single introduction. We also found evidence for secondary transmission from campers to the community. Together, these findings demonstrate that super-spreader events may occur during large gatherings of children.
RESUMO
ObjectiveThe severe acute respiratory syndrome-Coronavirus-2 (SARS-CoV-2) has caused a pandemic claiming more than 4 million lives worldwide. Overwhelming Coronavirus-Disease-2019 (COVID-19) respiratory failure placed tremendous demands on healthcare systems increasing the death toll. Cost-effective prognostic tools to characterize COVID-19 patients likely to progress to severe hypoxemic respiratory failure are still needed. DesignWe conducted a retrospective cohort study to develop a model utilizing demographic and clinical data collected in the first 12-hours admission to explore associations with severe hypoxemic respiratory failure in unvaccinated and hospitalized COVID-19 patients. SettingUniversity based healthcare system including 6 hospitals located in the Galveston, Brazoria and Harris counties of Texas. ParticipantsAdult patients diagnosed with COVID-19 and admitted to one of six hospitals between March 19th and June 31st, 2020. Primary outcomeThe primary outcome was defined as reaching a WHO ordinal scale between 6-9 at any time during admission, which corresponded to severe hypoxemic respiratory failure requiring high-flow oxygen supplementation or mechanical ventilation. ResultsWe included 329 participants in the model cohort and 62 (18.8%) met the primary outcome. Our multivariable regression model found that lactate dehydrogenase (OR 2.36), qSOFA score (OR: 2.26), and neutrophil to lymphocyte ratio (OR:1.15) were significant predictors of severe disease. The final model showed an area under curve (AUC) of 0.84. The sensitivity analysis and point of influence analysis did not reveal inconsistencies. ConclusionsOur study suggests that a combination of accessible demographic and clinical information collected on admission may predict the progression to severe COVID-19 among adult patients with mild and moderate disease. This model requires external validation prior to its use. STRENGTHS AND LIMITATIONS OF THIS STUDY Our study utilized objective and measurable demographic and clinical information regularly available in healthcare settings even among patients unable to communicate. Our primary outcome corresponds to WHO ordinal score which would allow compare our results to other studies and in other settings. Our model could serve as an effective point of service tool during early admission to assist in clinical management and allocation of resources to unvaccinated patients. Our study is a retrospective study of unvaccinated COVID19 patients, and validation of our prediction model in the rest of our study population is still needed. In addition, testing our model in a more recent cohort after emergence of new SARS-CoV-2 variants will be needed to assess its robustness.
