A Review of Vaccines Effective Against SARS‑CoV‑2: Introduction of Vaccine Production Strategies and Their Efficacy

Since an effective drug against Covid-19 was not approved, researchers worldwide are trying to develop an effective vaccine against the disease to prevent related morbidity and mortality. According to the latest report of the World Health Organization, August 5, 2022, there are about 170 vaccine candidates for SARS-coronavirus-2 in the clinical and 198 vaccine candidates in the pre-clinical stage. In this review article, emphasis is placed on only 7 vaccines that have passed clinical phase IV. The mechanism of action of most of the proposed vaccines is the induction of a neutralizing antibody against the spike protein (glycoprotein S). These antibodies prevent the virus from entering the host cell by blocking the virus from attaching to its cell receptor (ACE-2). In this review, the role of SARS-coronavirus-2 proteins in the viral replication cycle and its pathogenic mechanism, and also the variants of SARS-coronavirus-2 are discussed to have an overview of the goals of designed vaccines. Then, the technology of producing various types of vaccines and the effectiveness of these vaccines against the virus variants are discussed.