Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has caused a pandemic. As immunity to endemic human coronaviruses (i.e. NL63 or OC43) wanes leading to re-infection, it was unknown if SARS-CoV-2 immunity would also decline permitting repeat infections. Recent case reports confirm previously infected individuals can become re-infected; however, re-infection may be due to heterogeneity in the initial infection or the host immune response, or may be the result of infection with a variant strain that escapes pre-existing immunity. To control these variables, we utilized the Syrian hamster model to evaluate the duration of immunity and susceptibility to re-infection with SARS-CoV-2. Hamsters were given a primary mock or SARS-CoV-2 infection (culture media or 10 TCID50 USA/WA1/2020 isolate, respectively). Mock and SARS-CoV-2 infected hamsters were then given a secondary SARS-CoV-2 infection at 1, 2, 4, or 6 months post-primary infection ( = 14/time point/group). After the primary SARS-CoV-2 infection, hamsters developed anti-spike protein IgG, IgA, and neutralizing antibodies, and these antibodies were maintained for at least 6 months. Upon secondary SARS-CoV-2 challenge, previously SARS-CoV-2 infected animals were protected from weight loss, while all previously mock-infected animals became infected and lost weight. Importantly, despite having high titres of antibodies, one SARS-CoV-2 infected animal re-challenged at 4 months had a breakthrough infection with replicating virus in the upper and lower respiratory tract. These studies demonstrate immunity to SARS-CoV-2 is maintained for 6 months; however, protection may be incomplete and, even in the presence of high antibody titres, previously infected hosts may become re-infected.
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http://dx.doi.org/10.1080/22221751.2022.2058419 | DOI Listing |
Braz J Biol
January 2025
Near East University, Operational Research Center in Healthcare, Mersin, Turkey.
Amidst the ongoing COVID-19 pandemic, the imperative of our time resides in crafting stratagems of utmost precision to confront the relentless SARS-CoV-2 and quell its inexorable proliferation. A paradigm-shifting weapon in this battle lies in the realm of nanoparticles, where the amalgamation of cutting-edge nanochemistry begets a cornucopia of inventive techniques and methodologies designed to thwart the advances of this pernicious pathogen. Nanochemistry, an artful fusion of chemistry and nanoscience, provides a fertile landscape for researchers to craft innovative shields against infection.
View Article and Find Full Text PDFCien Saude Colet
January 2025
Faculdade de Saúde Pública, Universidade de São Paulo (USP). Av. Dr. Arnaldo 715, Cerqueira César. 01246-904 São Paulo SP Brasil.
The scope of this study was to analyze the impact of the COVID-19 pandemic on the incidence of occupational accidents among beneficiaries of the Unified Health System in Brazil. It was an interrupted time series study, using data on occupational accidents registered by the Unified Health System from 2015 to 2020. The analysis used the Prais-Winsten generalized linear regression model.
View Article and Find Full Text PDFSci Transl Med
January 2025
Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
At this stage in the COVID-19 pandemic, most infections are "breakthrough" infections that occur in individuals with prior severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exposure. To refine long-term vaccine strategies against emerging variants, we examined both innate and adaptive immunity in breakthrough infections. We performed single-cell transcriptomic, proteomic, and functional profiling of primary and breakthrough infections to compare immune responses from unvaccinated and vaccinated individuals during the SARS-CoV-2 Delta wave.
View Article and Find Full Text PDFSci Adv
January 2025
Department of Microbiology and Immunology, Cornell University College of Veterinary Medicine, Ithaca, NY 14853, USA.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza viruses lead to severe respiratory illnesses and death in humans, exacerbated in individuals with underlying health conditions, remaining substantial global public health concerns. Here, we developed a bivalent replication-incompetent single-cycle pseudotyped vesicular stomatitis virus vaccine that incorporates both a prefusion-stabilized SARS-CoV-2 spike protein lacking a furin cleavage site and a full-length influenza A virus neuraminidase protein. Vaccination of K18-hACE2 or C57BL/6J mouse models generated durable levels of neutralizing antibodies, T cell responses, and protection from morbidity and mortality upon challenge with either virus.
View Article and Find Full Text PDFPLoS One
January 2025
Department of Psychology, Toronto Metropolitan University, Toronto, Ontario, Canada.
During the COVID-19 pandemic, the use of videoconferencing platforms became ubiquitous in postsecondary education around the world, making it crucial to understand how to maximize the efficacy of synchronous online classes. Given that social information can act as a motivation and improve memory, the current study tested the hypothesis that brief social presence during an online class would act as a social reward that would increase delayed memory for lecture information. Undergraduate students attended a mock synchronous class during which they viewed a pre-recorded science lecture, and social presence was manipulated by having participants turn on their cameras before and after the lecture (high social presence) or having cameras remain off during the entire class (low social presence).
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