Covid-19 vaccines in nasal spray

Out of 100 Covid-19 vaccines in clinical trials, 7 are in nasal spray form.

Phase I tests in mice indicate that the sprays provide a powerful local immune response. Inhalation of the vaccine reduces the presence of the virus after two days. Cells in contact with the spray develop antibodies that reduce virus replication and prevent airway infection.

Initial results of the spray vaccines are promising. However, they provide a shorter immune protection than intramuscular vaccines.