Infection with SARS-CoV-2 variant Gamma (P.1) in Chile increased ICU admission risk three to five-fold.

The 2021 wave of SARS-CoV-2 infection in Chile was characterized by an explosive increase in ICU admissions, which disproportionately affected individuals younger than 60 years. This second wave was also accompanied by an explosive increase in Gamma (P.1) variant detections and the massive vaccine rollout. We unveil the role the Gamma variant played in stressing the use of critical care, by developing and calibrating a queueing model that uses data on new onset cases and actual ICU occupancy, symptom's onset to ICU admission interval, ICU length-of-stay, genomic surveillance, and vaccine effectiveness. Our model shows that infection with the Gamma (P.1) variant led to a 3.5-4.7-fold increase in ICU admission for people younger than 60 years. This situation occurred on top of the already reported higher infection rate of the Gamma variant. Importantly, our results also strongly suggest that the vaccines used in Chile (inactivated mostly, but also an mRNA), were able to curb Gamma variant ICU admission over infections.

Multisystem Inflammatory Syndrome in Children in Western Countries? Decreasing Incidence as the Pandemic Progresses?: An Observational Multicenter International Cross-sectional Study.

BACKGROUND: SARS-CoV-2 variations as well as immune protection after previous infections and/or vaccination may have altered the incidence of multisystemic inflammatory syndrome in children (MIS-C). We aimed to report an international time-series analysis of the incidence of MIS-C to determine if there was a shift in the regions or countries included into the study. METHODS: This is a multicenter, international, cross-sectional study. We collected the MIS-C incidence from the participant regions and countries for the period July 2020 to November 2021. We assessed the ratio between MIS-C cases and COVID-19 pediatric cases in children <18 years diagnosed 4 weeks earlier (average time for the temporal association observed in this disease) for the study period. We performed a binomial regression analysis for 8 participating sites [Bogotá (Colombia), Chile, Costa Rica, Lazio (Italy), Mexico DF, Panama, The Netherlands and Catalonia (Spain)]. RESULTS: We included 904 cases of MIS-C, among a reference population of 17,906,432 children. We estimated a global significant decrease trend ratio in MIS-C cases/COVID-19 diagnosed cases in the previous month ( P < 0.001). When analyzing separately each of the sites, Chile and The Netherlands maintained a significant decrease trend ( P < 0.001), but this ratio was not statistically significant for the rest of sites. CONCLUSIONS: To our knowledge, this is the first international study describing a global reduction in the trend of the MIS-C incidence during the pandemic. COVID-19 vaccination and other factors possibly linked to the virus itself and/or community transmission may have played a role in preventing new MIS-C cases.

Multisystem inflammatory syndrome in children (MIS-C): Report of the clinical and epidemiological characteristics of cases in Santiago de Chile during the SARS-CoV-2 pandemic.

OBJECTIVE: To describe the clinical and epidemiological characteristics of hospitalized children with multisystem inflammatory syndrome in children (MIS-C) in Santiago, Chile. METHODS: This was an observational study of children with MIS-C (May 1 to June 24, 2020), in three pediatric hospitals in Santiago. Demographic characteristics and epidemiological data, medical history, laboratory tests, cardiology evaluations, treatment, and clinical outcomes were analyzed. RESULTS: Twenty-seven patients were admitted (median age 6, range 0-14 years). Sixteen of the 27 (59%) required intensive care unit admission; there were no deaths. Seventy-four percent had no comorbidities, and the median number of days of symptoms before admission was 4 (range 2-9 days). Gastrointestinal symptoms were the most frequent, and inflammatory markers were increased at admission. A recent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection was detected in 82% of cases. The severe group showed significantly lower hemoglobin and albumin levels, decreased platelet counts, and higher d-dimer during disease evolution. Echocardiography showed abnormalities (myocardial, pericardial, or coronary) in 12 patients (46%) during their hospital stay. Anti-inflammatory treatment (immunoglobulin and/or corticosteroids) was prescribed in 24 patients. MIS-C appeared in clusters weeks after the peak of SARS-CoV-2 cases, especially in the most vulnerable areas of Santiago. CONCLUSIONS: This study describes the first series (n = 27) of children with MIS-C in a Latin American country, showing favorable clinical outcomes. Education and alerts are required for clinical teams to establish an early diagnosis and prompt treatment.

Optimizing RT-PCR detection of SARS-CoV-2 for developing countries using pool testing

The global shortage of reagents and kits for nucleic acid extraction and molecular detection of SARS-CoV-2 requires new cost-effective strategies for the diagnosis of suspected COVID-19 cases, especially in countries that need to increase detection capacity. Pooled nucleic acid testing has been extensively used as a cost-effective strategy for HIV, HepB, HepC and influenza. Also, protocols dispensing of RNA extraction appears as an attractive option for detection of SARS-CoV-2. In this study, we found that pooling of 5 samples showed that CT variations were in the range of 1.0-4,5 units, with less likelihood of a false negative result. Results of the sample without nucleic acid ex-traction, was unsatisfactory, with a significant increase in CT values, and thus for risk of a false negative result. In conclusion, pooling nasopharyngeal samples with both automated and manual extraction proved reliable, and thus a potential efficient alternative for the diagnosis of suspected COVID-19 in developing countries. Resumen La escasez mundial de reactivos para la extracción de ácidos nucleicos y la detección molecular de SARS-CoV-2 requiere de nuevas estrategias de mayor rendimiento para el diagnóstico de casos sospechosos de COVID-19, especialmente en países que necesitan aumentar su capacidad diagnóstica. La detección de ácidos nucleicos en muestras agrupadas o pool testing se ha utilizado ampliamente como una estrategia costo-efectiva para el VIH, hepatitis B, hepatitis C e influenza. Adicionalmente, los protocolos que no requieren extracción de ARN aparecen como una opción para la detección de SARS-CoV-2. En este trabajo, presentamos los resultados de una estrategia detección de SARS-CoV-2 en muestras agrupadas, que incluye diferentes métodos de extracción de ARN que puede ser una estrategia atractiva para los países en desarrollo. La agrupación de 5 muestras mostró variaciones CT en el rango de 1,0 a 4,5 unidades, con una baja probabilidad de obtener falsos negativos, a diferencias de los resultados agregando muestras agrupadas directamente en la reacción de amplificación de SARS-CoV-2. En conclusión, la agrupación de muestras nasofaríngeas, demostró ser un método confiable y, por lo tanto, una alternativa para aumentar el rendimiento en el diagnóstico de COVID-19 para países en desarrollo.

Optimizing RT-PCR detection of SARS-CoV-2 for developing countries using pool testing.

The global shortage of reagents and kits for nucleic acid extraction and molecular detection of SARS-CoV-2 requires new cost-effective strategies for the diagnosis of suspected COVID-19 cases, especially in countries that need to increase detection capacity. Pooled nucleic acid testing has been extensively used as a cost-effective strategy for HIV, HepB, HepC and influenza. Also, protocols dispensing of RNA extraction appears as an attractive option for detection of SARS-CoV-2. In this study, we found that pooling of 5 samples showed that CT variations were in the range of 1.0-4,5 units, with less likelihood of a false negative result. Results of the sample without nucleic acid ex-traction, was unsatisfactory, with a significant increase in CT values, and thus for risk of a false negative result. In conclusion, pooling nasopharyngeal samples with both automated and manual extraction proved reliable, and thus a potential efficient alternative for the diagnosis of suspected COVID-19 in developing countries.