ABSTRACT
The performance and validity of the COVISTIXTM rapid antigen test for the detection of SARS-CoV-2 were evaluated in an unselected population. Additionally, we assessed the influence of the Omicron SARS-CoV-2 variant in the performance of this antigen rapid test. Swab samples were collected at two point-of-care facilities in Mexico City from individuals that were probable COVID-19 cases, as they were either symptomatic or asymptomatic persons at risk of infection due to close contact with SARS-CoV-2 positive cases. Detection of the Omicron SARS-CoV-2 variant was performed in 91 positive cases by Illumina sequencing. Specificity and sensitivity of the COVISTIXTM rapid antigen test was 96% (CI 95% 94-98) and 81% (CI 95% 76-85), respectively. The accuracy parameters were not affected in samples collected after 7 days of symptom onset, and it was possible to detect almost 65% of samples with a Ct-value between 30 and 34. The COVISTIXTM antigen rapid test is highly sensitive (93%; CI 95% 88-98) and specific (98%; CI 95% 97-99) for detecting Omicron SARS-CoV-2 variant carriers. The COVISTIXTM rapid antigen test is adequate for examining asymptomatic and symptomatic individuals, including those who have passed the peak of viral shedding, as well as carriers of the highly prevalent Omicron SARS-CoV-2 variant.
ABSTRACT
INTRODUCTION: In response to the evolution of the coronavirus disease 2019 (COVID-19) pandemic, the admission protocol for the temporary COVID-19 hospital in Mexico City has been updated to hospitalize patients preemptively with an oxygen saturation (SpO2) of >90%. METHODS: This prospective, observational, single-center study compared the progression and outcomes of patients who were preemptively hospitalized versus those who were hospitalized based on an SpO2 ⩽90%. We recorded patient demographics, clinical characteristics, COVID-19 symptoms, and oxygen requirement at admission. We calculated the risk of disease progression and the benefit of preemptive hospitalization, stratified by CALL Score: age, lymphocyte count, and lactate dehydrogenase (<8 and ⩾8) at admission. RESULTS: Preemptive hospitalization significantly reduced the requirement for oxygen therapy (odds ratio 0.45, 95% confidence interval 0.31-0.66), admission to the intensive care unit (ICU) (0.37, 0.23-0.60), requirement for invasive mechanical ventilation (IMV) (0.40, 0.25-0.64), and mortality (0.22, 0.10-0.50). Stratification by CALL score at admission showed that the benefit of preemptive hospitalization remained significant for patients requiring oxygen therapy (0.51, 0.31-0.83), admission to the ICU (0.48, 0.27-0.86), and IMV (0.51, 0.28-0.92). Mortality risk remained significantly reduced (0.19, 0.07-0.48). CONCLUSION: Preemptive hospitalization reduced the rate of disease progression and may be beneficial for improving COVID-19 patient outcomes.