Characterisation of the Antibody Response in Sinopharm (BBIBP-CorV) Recipients and COVID-19 Convalescent Sera from the Republic of Moldova.

The early availability of effective vaccines against SARS-CoV-2, the aetiologic cause of COVID-19, has been at the cornerstone of the global recovery from the pandemic. This study aimed to assess the antispike RBD IgG antibody titres and neutralisation potential of COVID-19 convalescent plasma and the sera of Moldovan adults vaccinated with the Sinopharm BBIBP-CorV vaccine. An IgG ELISA with recombinant SARS-CoV-2 spike RBD and two pseudovirus-based neutralisation assays have been developed to evaluate neutralising antibodies against SARS-CoV-2 in biosafety level 2 containment facilities. A significant moderate correlation was observed between IgG titres and the overall neutralising levels for each neutralisation assay (ρ = 0.64, p < 0.001; ρ = 0.52, p < 0.001). A separate analysis of convalescent and vaccinated individuals showed a higher correlation of neutralising and IgG titres in convalescent individuals (ρ = 0.68, p < 0.001, ρ = 0.45, p < 0.001) compared with vaccinated individuals (ρ = 0.58, p < 0.001; ρ = 0.53, p < 0.001). It can be concluded that individuals who recovered from infection developed higher levels of antispike RBD IgG antibodies. In comparison, the Sinopharm-vaccinated individuals produced higher levels of neutralising antibodies than convalescent plasma.

Genome Sequences of SARS-CoV-2 Strains from the Republic of Moldova.

The whole-genome sequences of 15 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) strains from nasopharyngeal swab samples collected in the Republic of Moldova in June 2020 to September 2021 were determined. Little variability was observed in the early stages, when mostly clade 19A was circulating, followed by clade 20B. Later, multiple introductions of SARS-CoV-2 lineages B.1.1., B.1.1.7, and B.1.1.525 were detected. The B.1.1.7 lineage became predominant between December 2020 and June 2021, followed by the Delta variant.

EVs vs. EVs: MSCs and Tregs as a source of invisible possibilities.

Extracellular vesicles (EVs) are produced by various cells and exist in most biological fluids. They play an important role in cell-cell signaling, immune response, and tumor metastasis, and also have theranostic potential. They deliver many functional biomolecules, including DNA, microRNAs (miRNA), messenger RNA (mRNA), long non-coding RNA (lncRNA), lipids, and proteins, thus affecting different physiological processes in target cells. Decreased immunogenicity compared to liposomes or viral vectors and the ability to cross through physiological barriers such as the blood-brain barrier make them an attractive and innovative option as diagnostic biomarkers and therapeutic carriers. Here, we highlighted two types of cells that can produce functional EVs, namely, mesenchymal stem/stromal cells (MSCs) and regulatory T cells (Tregs), discussing MSC/Treg-derived EV-based therapies for some specific diseases including acute respiratory distress syndrome (ARDS), autoimmune diseases, and cancer.

Screening, Diagnostic and Prognostic Tests for COVID-19: A Comprehensive Review.

While molecular testing with real-time polymerase chain reaction (RT-PCR) remains the gold-standard test for COVID-19 diagnosis and screening, more rapid or affordable molecular and antigen testing options have been developed. More affordable, point-of-care antigen testing, despite being less sensitive compared to molecular assays, might be preferable for wider screening initiatives. Simple laboratory, imaging and clinical parameters could facilitate prognostication and triage. This comprehensive review summarises current evidence on the diagnostic, screening and prognostic tests for COVID-19.