Background: The COVID-19 pandemic has been the most significant health challenge of the last century. Multiple and successive waves of COVID-19 cases, driven particularly by the emergence of new SARS-CoV-2 variants, have kept the world in a constant state of alert.
Methods: We present an observational, descriptive, cross-sectional study aimed at identifying SARS-CoV-2 variants circulating during two local waves of COVID-19 cases in southern Bahia, Brazil (late 2021 and late 2022), and analyzing the association between the detected variants and the epidemiological and clinical characteristics of the disease. For this purpose, data and nasopharyngeal samples from individuals in southern Bahia, Brazil, with suspected COVID-19 were included. Viral detection was performed by RT-qPCR, and SARS-CoV-2 variants were identified by next-generation viral sequencing.
Results: A total of 368 nasopharyngeal samples were tested. Approximately 23% of the samples from late 2021 tested positive for SARS-CoV-2, while in 2022, the positivity rate was about 56%. All sequenced samples from 2021 were identified as the Delta variant, while in 2022, all samples were classified as the Omicron variant. Overall, individuals who tested positive for SARS-CoV-2 in 2022 were younger than those who tested positive in 2021. Moreover, we observed significant differences in the clinical spectrum of SARS-CoV-2 infection when comparing the two periods. Individuals who presented with anosmia/ageusia were more likely to test positive for SARS-CoV-2 infection in 2021 but not in 2022. Additionally, fever, dry cough, pharyngalgia, headache, and rhinorrhea were more frequent among individuals infected with the Omicron variant than among those infected with the Delta variant.
Conclusions: The profile of COVID-19 in southern Bahia differed when analyzing two distinct waves of the pandemic in the region. These differences are likely related to the variants, which may differ in transmissibility and virulence, thereby altering the dynamics of the pandemic. This underscores the importance of genomic surveillance in better understanding the behavior of viral infections.
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http://dx.doi.org/10.1186/s12985-024-02538-0 | DOI Listing |
Elife
December 2024
Department of Medical Informatics, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
An unprecedented amount of SARS-CoV-2 data has been accumulated compared with previous infectious diseases, enabling insights into its evolutionary process and more thorough analyses. This study investigates SARS-CoV-2 features as it evolved to evaluate its infectivity. We examined viral sequences and identified the polarity of amino acids in the receptor binding motif (RBM) region.
View Article and Find Full Text PDFFront Immunol
December 2024
Department of Microbiology and Cell Biology, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan.
Introduction: To analyze the molecular pathogenesis of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), a small animal model such as mice is needed: human angiotensin converting enzyme 2 (hACE2), the receptor of SARS-CoV-2, needs to be expressed in the respiratory tract of mice.
Methods: We conferred SARS-CoV-2 susceptibility in mice by using an adenoviral vector expressing hACE2 driven by an elongation factor 1α (EF1α) promoter with a leftward orientation.
Results: In this model, severe pneumonia like human COVID-19 was observed in SARS-CoV-2-infected mice, which was confirmed by dramatic infiltration of inflammatory cells in the lung with efficient viral replication.
J Med Virol
December 2024
Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China.
SARS-CoV-2 continues to mutate, leading to breakthrough infections. The development of new vaccine strategies to combat various strains is crucial. Protein cyclization can enhance thermal stability and may improve immunogenicity.
View Article and Find Full Text PDFAnn Med
December 2025
Department of Pediatrics, Kawasaki Disease Center, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan.
Background: Vaccination is one of the best ways to control the SARS-CoV-2 outbreak. In Taiwan, healthcare workers were prioritized for vaccination, but the effectiveness of these vaccines for them remains unclear. Thus, it's essential to examine their neutralizing antibodies after prime-boost vaccinations.
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