New vaccine is administered through a nasal spray similar to those commonly used to vaccinate against influenza. The vaccine used in the study only requires a single dose and it may be stored at normal refrigerator temperatures for up to at least three months. Because it is given intranasally, the vaccine may also be easier to administer, especially for those who have a fear of needles.

“We have been developing this vaccine platform for more than 20 years, and we began working on new vaccine formulations to combat COVID-19 during the early days of the pandemic,” says Biao He, PhD, a professor in the University of Georgia’s Department of Infectious Diseases in the College of Veterinary Medicine and co-leader of the study.

“Our preclinical data show that this vaccine not only protects against infection, but also significantly reduces the chances of transmission.”

It uses a harmless parainfluenza virus 5 (PIV5) to deliver the SARS-CoV-2 spike protein into cells where it prompts an immune response that protects against COVID-19 infection. PIV5 is related to common cold viruses and easily infects different mammals, including humans, without causing significant disease.

This vaccine platform can completely protect experimental animals from another dangerous coronavirus disease called Middle Eastern Respiratory Syndrome (MERS).

The inhaled PIV5 vaccine developed by the team targets mucosal cells that line the nasal passages and airways. These cells are the main entry point for most SARS-CoV-2 infections and the site of early virus replication.

Virus produced in these cells can invade deeper into the lungs and other organs in the body, which can lead to more severe disease. Virus made in these cells can be easily shed through exhalation allowing transmission from one infected person to others.

Vaccine produced a localized immune response, involving antibodies and cellular immunity, that completely protected mice from fatal doses of SARS-CoV-2. The vaccine also prevented infection and disease in ferrets and, importantly, appeared to block transmission of COVID-19 from infected ferrets to their unprotected and uninfected cage-mates.

Source: Medindia