Adenovirus-Based Single-Dose Vaccines for SARS-CoV-2: A Review

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak has many unexpected implications, but the scientific community remains optimistic about overcoming these obstacles. Adenoviruses (Ad) are considered the most suitable vectors for transferring specific antigens to mammalian cells since they can induce both innate and adaptive immune responses. Ad-based coronavirus disease 2019 (COVID-19). vaccines were granted emergency use authorization in the COVID-19 pandemic. Many features of the Ad vector render it an appealing vaccine carrier for contagious diseases, including high titer, ease of processing, high effectiveness, low immunogenicity in clinical trials, and consistency in pharmaceutical packaging and shipment processes. Ad-based vaccines are generally effective and have few side effects since Ad induces minor infections in humans, and genetic modifications can block viral replication. These single-dose vaccines are effective not only in young individuals but also in adults. Clinical trials of these single-dose vaccines are commendable and have shown excellent safety and efficacy profiles. This review provides a summary of the development of single-dose vaccines against SARS-CoV-2.