Nasal vaccines for COVID-19: Current trends and future perspectives

Abstract

Coronavirus disease (COVID-19), a highly contagious viral respiratory illness, has resulted in widespread human losses, as well as posing more newer difficulties to the global health infrastructure. Vaccination has been a powerful public health tool for preventing deadly diseases, and it is still the most effective weapon when dealing with pandemics. Intranasal vaccines form an important part of the next-generation vaccines being developed to bolster our arsenal against infectious diseases. Nasal delivery of vaccines induces both systemic and local mucosal immune responses to help scale up the war against the inhaled pathogens. Owing to its simplicity, ease, convenience, safety, and higher effectivity, intranasal vaccines are turning out to be a promising alternative to the parenteral and other mucosal routes of administration. Intranasal vaccines are considered more efficacious than conventional parenteral injectable vaccines for influenza virus. The vaccination rate can be increased as the intranasal vaccine is directly delivered into nasal cavity and involves less cumbersome and painless procedure than intravenous administration. Nasal mucosa is an easily accessible organ with rich vascular supply and large surface area available for absorption aiding in quick absorption of vaccine. Furthermore, the intranasal vaccines are more affordable than the conventional vaccines.