Fig. 6

Novel therapies and their administration. Drug/vaccine route of administration: nasal, oral, and parenteral administration. Most conventional coronavirus disease 19 vaccines require cold storage and intramuscular administration to activate systemic immunity, such as BNT162b2, an RNA vaccine packaged with lipid nanoparticles. Mucosal vaccines are administered intranasally or orally. Oral vaccines targeting sublingual and intestinal mucosal immunity are usually stored at room temperature because they can withstand harsh conditions in the gastrointestinal tract. Vaxart and IosBio oral vaccines, both adenovirus vectors, have been developed into capsules and pills for ease of administration. Recombinant oral vaccines based on virus-like particles, can also be stored at room temperature in liquid form. Function of intranasal vaccines in the respiratory tract: viruses, exosomes, and extracellular vesicles can be used as vectors to carry the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) spike protein or its optimized gene codes. Intranasal vaccines are atomized into small droplets using a nebulizer and inhaled, exerting their effects on the nasal cavity and airway. Inhaled antibodies are used as therapeutic agents. They have instant effects because inhaled neutralizing antibodies or antibody fragments are directed to the respiratory tract, where SARS-CoV-2 is rampant, neutralizing viruses and inhibiting their replication