The Lambda Variant in Argentina: Analyzing the Evolution and Spread of SARS-CoV-2 Lineage C.37.

The second wave of COVID-19 occurred in South America in early 2021 and was mainly driven by Gamma and Lambda variants. In this study, we aimed to describe the emergence and local genomic diversity of the SARS-CoV-2 Lambda variant in Argentina, from its initial entry into the country until its detection ceased. Molecular surveillance was conducted on 9356 samples from Argentina between October 2020 and April 2022, and sequencing, phylogenetic, and phylogeographic analyses were performed. Our findings revealed that the Lambda variant was first detected in Argentina in January 2021 and steadily increased in frequency until it peaked in April 2021, with continued detection throughout the year. Phylodynamic analyses showed that at least 18 introductions of the Lambda variant into the country occurred, with nine of them having evidence of onward local transmission. The spatial--temporal reconstruction showed that Argentine clades were associated with Lambda sequences from Latin America and suggested an initial diversification in the Metropolitan Area of Buenos Aires before spreading to other regions in Argentina. Genetic analyses of genome sequences allowed us to describe the mutational patterns of the Argentine Lambda sequences and detect the emergence of rare mutations in an immunocompromised patient. Our study highlights the importance of genomic surveillance in identifying the introduction and geographical distribution of the SARS-CoV-2 Lambda variant, as well as in monitoring the emergence of mutations that could be involved in the evolutionary leaps that characterize variants of concern.

Omicron Waves in Argentina: Dynamics of SARS-CoV-2 Lineages BA.1, BA.2 and the Emerging BA.2.12.1 and BA.4/BA.5.

The COVID-19 pandemic has lately been driven by Omicron. This work aimed to study the dynamics of SARS-CoV-2 Omicron lineages during the third and fourth waves of COVID-19 in Argentina. Molecular surveillance was performed on 3431 samples from Argentina, between EW44/2021 and EW31/2022. Sequencing, phylogenetic and phylodynamic analyses were performed. A differential dynamic between the Omicron waves was found. The third wave was associated with lineage BA.1, characterized by a high number of cases, very fast displacement of Delta, doubling times of 3.3 days and a low level of lineage diversity and clustering. In contrast, the fourth wave was longer but associated with a lower number of cases, initially caused by BA.2, and later by BA.4/BA.5, with doubling times of about 10 days. Several BA.2 and BA.4/BA.5 sublineages and introductions were detected, although very few clusters with a constrained geographical distribution were observed, suggesting limited transmission chains. The differential dynamic could be due to waning immunity and an increase in population gatherings in the BA.1 wave, and a boosted population (for vaccination or recent prior immunity for BA.1 infection) in the wave caused by BA2/BA.4/BA.5, which may have limited the establishment of the new lineages.

Severe Acute Respiratory Syndrome Coronavirus 2 Pandemic: Chilean Air Force Experience in the Air Transport of Critically Ill Patients-The First 100 Cases.

OBJECTIVE: Critical care air transport has played an important role during the coronavirus disease 2019 (COVID-19) pandemic. The goal of this article is to analyze results and lessons learned from the evacuation of the first 100 COVID-19 patients transported between medical facilities in Chile. METHODS: We reviewed prospective data of patients who were referred for air transport between March 27, 2020, and July 9, 2020. RESULTS: Of 115 referred patients, 100 were transported by air. All patients were intubated and mechanically ventilated. Hypertension, diabetes, and obesity were the most commonly observed comorbidities. Our service did not experience any major problems in patient care en route or among the crewmembers. We did not observe any severe acute respiratory syndrome coronavirus 2 infections among our flight team members during the study period. Twelve (12%) patients died at their destination intensive care unit, whereas the remaining 88 patients (88%) returned to their primary hospitals after recovery. CONCLUSIONS: Air transport of mechanically ventilated patients with COVID-19 infection has been shown to be a safe way of transport, with no in-flight deaths and an in-hospital mortality of 12%, which compares favorably with the in-hospital mortality of similar patients who did not undergo air transport.