Immunology of SARS-CoV-2 Infection.

According to the data from the World Health Organization, about 800 million of the world population had contracted coronavirus infection caused by SARS-CoV-2 by mid-2023. Properties of this virus have allowed it to circulate in the human population for a long time, evolving defense mechanisms against the host immune system. Severity of the disease depends largely on the degree of activation of the systemic immune response, including overstimulation of macrophages and monocytes, cytokine production, and triggering of adaptive T- and B-cell responses, while SARS-CoV-2 evades the immune system actions.

Biology of the SARS-CoV-2 Coronavirus.

New coronavirus infection causing COVID-19, which was first reported in late 2019 in China, initiated severe social and economic crisis that affected the whole world. High frequency of the errors in replication of RNA viruses, zoonotic nature of transmission, and high transmissibility allowed betacoronaviruses to cause the third pandemic in the world since the beginning of 2003: SARS-CoV in 2003, MERS-CoV in 2012, and SARS-CoV-2 in 2019. The latest pandemic united scientific community and served as a powerful impetus in the study of biology of coronaviruses: new routes of virus penetration into the human cells were identified, features of the replication cycle were studied, and new functions of coronavirus proteins were elucidated.