A COVID-19 vaccine candidate administered through the nose was shown to lead to a reduction in the impact of the disease as well as virus transmission in pre-clinical animal trials. 

Hamsters were inoculated with two doses of the intranasal vaccine and exhibited complete protection from lung infection, inflammation and lesions after being exposed to the SARS-CoV-2 virus. Two doses of the intranasal vaccine also led to significant reduction in virus shedding from the nose and lungs of the animals, thus highlighting that the vaccine can control infection at the site of inoculation.

This vaccine is based on a common poultry virus - Newcastle Disease Virus (NDV) - which has the potential to reproduce in humans but is not harmful… (ET Healthworld – PTI, August 11, 2021)