Ekramy Sayedahmed: Writing\original draft; Writing\review & editing. and are broadly protective against emerging and re\emerging infectious diseases. Extensive knowledge of the molecular biology and immunology of adenoviruses (Ad) has favored Ad vectors as platforms for vaccine design. The Ad\based vaccine platform represents an attractive strategy as it induces robust humoral and cell\mediated immune responses and can meet the global demand in a pandemic situation. This review describes the status of Ad vector\based vaccines in preclinical and clinical studies for current and emerging respiratory viruses, particularly coronaviruses, influenza viruses and respiratory syncytial viruses. Ag85A protein. 246 , 247 A BAd\based TB vaccine expressing an immunogenic epitope of Ag85B has demonstrated excellent potential in a challenge study in mice. 248 While the Ad platform has shown remarkable results; it may be a better choice for pathogens of high virulence and pandemic potential. There could be a concern that this frequent use of an Ad vector platform will develop widespread pre\existing Ad immunity, which would dampen the effectiveness of that particular Ad vector system. However, because of the availability of several human and nonhuman Ad\based vaccine platforms, the issue of pre\existing or vaccine\induced Ad immunity could easily be handled by alternate use of two or more Ad vector systems. Further studies are needed to fully explore the roles of other routes, including intradermal, s.c., i.n. and oral in inducing improved immune responses with various Ad vectors. Other delivery devices, such as skin patches and nanoparticles, should be tried for targeting specialised cells and prolonging the duration of vector\transduced cells KRAS G12C inhibitor 13 for enhanced immune responses. It is crucial to modify Ad vectors for better targeting of APCs and superior processing of immunogenic epitopes within various compartments of vector\infected cells. The next generation of Ad vectors may be designed having limited capability to replicate or express self\replicating mRNA for improved durability of antigen\specific immune responses. The role of primary and boost with two different Ad vectors in inducing enhanced, broad and durable immune responses needs to be further investigated. KRAS G12C inhibitor 13 Conflicts of interest The authors declare no conflicts of interest. Author contribution Ahmed Elkashif: Conceptualization; Writing\original draft; Writing\review & editing. Marwa Alhashimi: Writing\original Rabbit Polyclonal to FANCG (phospho-Ser383) draft; Writing\review & editing. Ekramy Sayedahmed: Writing\original draft; Writing\review & editing. Suryaprakash Sambhara: Conceptualization; Supervision; Writing\review & editing. Suresh K Mittal: Conceptualization; Funding acquisition; Supervision; Writing\original draft; Writing\review & editing. Acknowledgments This work was supported by Public Health Service grants AI059374 and AI158177 from the National Institute of Allergy and Infectious Diseases. We are grateful to Paolo Nazzari for helping us in preparing high\resolution figures. Notes Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention, US Department of Health and KRAS G12C inhibitor 13 Human Services. Contributor Information Suryaprakash Sambhara, Email: vog.cdc@arahbmass. Suresh K Mittal, Email: ude.eudrup@lattim..