Adjuvant Option for Effective SARS-CoV-2 Vaccine

Coronavirus Disease 2019 (COVID-19), caused by SARS-CoV-2 infection, has spread all over the world as an emerging infectious disease, causing a very serious impact on the global economy and public health. To date, there is no specific treatment or vaccines against coronaviruses. To prevent the infection and stop the pandemic, the research and development of effective SARS-CoV-2 vaccines has become an urgent matter. It is worth mentioning that appropriate adjuvants could enhance the strength and speed of the immune responses to vaccination. However, it takes time to customize different adjuvants with distinct targets (cellular or humoral immunity) and action intensity according to different antigens. In this review, we summarize the mechanism, advantages and disadvantages of adjuvants commonly used in licensed vaccines, as well as some novel adjuvants under development, hoping to provide information and increase the chances of success in developing effective SARS-CoV-2 vaccines in a short time frame.