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COVID-19 vaccines, immunity, and new variants: The role of T cells
mutate constantly. Consequently, numerous SARS-CoV-2 variants have emerged as the COVID-19 pandemic has progressed.A few SARS-CoV-2 variants have shown increased transmissibility, with the World Health Organization (WHO) designating them as “variants of concern (VOC).” These VOCs include the alpha (B.1.1.7), beta (B.1.351), delta (B.1.617.2), and gamma (P.1) that originated in the United Kingdom, South Africa, India, and Brazil, respectively.