Development of an intranasal SARS-CoV-2 vaccine Implementing the Newcastle disease virus vector platform

Most current coronavirus disease 2019 (COVID-19) vaccines protect from severe disease, but fail at preventing asymptomatic infections and onward transmission. We developed a Newcastle disease virus (NDV)-based vaccine that expresses a stabilized version of the SARS-CoV-2 spike protein on its surface. The vaccine is named NDV-HXP-S and similar to influenza vaccines can be produced in embryonated eggs. This enables production at low cost and large scale in existing influenza vaccine production facilities, allowing for low and middle-income countries to cover their own demand. As demonstrated in this thesis, NDV-HXP-S can easily be adapted to variants of concern (VOCs) and is efficacious when administered intranasally. Intranasal vaccination of mice with NDV-HXP-S induces not only systemic immunity, but also immune responses in the upper respiratory tract, the gut and the genitourinary tract. Mice and hamsters are protected after immunization with NDV-HXP-S and have reduced viral replication and shedding, thereby completely preventing transmission of the virus to naïve co-housed animals.