The article discusses the development of vaccines against COVID-19, focusing on the viral elements used as targets and the implications for protective immunity. As of December 3, 2020, the pandemic had spread to 220 countries with over 63 million confirmed cases and 1.4 million deaths. The development of a safe and effective vaccine is crucial to ending the pandemic. SARS-CoV-2, the virus causing COVID-19, belongs to the *Coronaviridae* family, and previous vaccine development experiences for animal and human CoVs provide valuable insights. The article highlights the importance of both humoral and cellular immunity in protection, with neutralizing antibodies (nAbs) and T cell responses playing critical roles. However, there is a risk of vaccine-enhanced disease (ADE) and enhanced respiratory disease (ERD) due to the potential for antibodies to bind to the virus without neutralizing activity. Various vaccine strategies are being explored, including inactivated virus, virus-like particle, protein subunit, virus-vectored, DNA and mRNA vaccines, and live-attenuated virus vaccines. The S protein, particularly the receptor-binding domain (RBD), is a major target for vaccine development due to its immunogenicity and role in virus entry. Several vaccine candidates based on the S protein have entered clinical trials, showing promising results. The article also discusses the challenges and considerations in vaccine design, such as the need to balance viral clearance and immunopathogenesis, and the potential for mucosal vaccination to induce immune responses at the respiratory tract. Overall, the article provides an overview of the current state of vaccine development and the scientific rationale behind the chosen targets.The article discusses the development of vaccines against COVID-19, focusing on the viral elements used as targets and the implications for protective immunity. As of December 3, 2020, the pandemic had spread to 220 countries with over 63 million confirmed cases and 1.4 million deaths. The development of a safe and effective vaccine is crucial to ending the pandemic. SARS-CoV-2, the virus causing COVID-19, belongs to the *Coronaviridae* family, and previous vaccine development experiences for animal and human CoVs provide valuable insights. The article highlights the importance of both humoral and cellular immunity in protection, with neutralizing antibodies (nAbs) and T cell responses playing critical roles. However, there is a risk of vaccine-enhanced disease (ADE) and enhanced respiratory disease (ERD) due to the potential for antibodies to bind to the virus without neutralizing activity. Various vaccine strategies are being explored, including inactivated virus, virus-like particle, protein subunit, virus-vectored, DNA and mRNA vaccines, and live-attenuated virus vaccines. The S protein, particularly the receptor-binding domain (RBD), is a major target for vaccine development due to its immunogenicity and role in virus entry. Several vaccine candidates based on the S protein have entered clinical trials, showing promising results. The article also discusses the challenges and considerations in vaccine design, such as the need to balance viral clearance and immunopathogenesis, and the potential for mucosal vaccination to induce immune responses at the respiratory tract. Overall, the article provides an overview of the current state of vaccine development and the scientific rationale behind the chosen targets.