According to a new study, it has been seen found that a new single-dose intranasal COVID-19 vaccine fully protects mice against lethal infection, and also blocks transmission of the SARS-CoV-2 virus in ferrets.
This study of the new vaccine has been described in the journal Science Advances that is administered through a nasal spray that is similar to those commonly used to vaccinate against influenza.
This new method is unlike the currently approved COVID-19 vaccines that require an injection.
Paul McCray, a professor of at University of Georgia, US said, “The currently available vaccines against COVID-19 are very successful, but the majority of the world’s population is still unvaccinated and there is a critical need for more vaccines that are easy to use and effective at stopping disease and transmission.”
“If this new COVID-19 vaccine proves effective in people, it may help block SARS-CoV-2 transmission and help control the COVID-19 pandemic,” McCray, co-leader of the study, said.
It was noted by the researchers that the vaccine only needs a single dose and can be stored at normal temperatures in the refrigerator for up to at least three months. They said, as the dose is given intranasally, the vaccine may also be easier to administer, especially for those who have a fear of needles.
Biao He, a professor at the University of Georgia, and co-leader of the study said, “Our preclinical data show that this vaccine not only protects against infection but also significantly reduces the chances of transmission.”
To deliver the SARS-CoV-2 spike protein into cells where it prompts an immune response that protects against coronavirus infection this experimental vaccine uses a harmless parainfluenza virus 5 (PIV5).
The spike protein helps the virus to enter and infect human cells, and vaccines are directed against it and PIV5 is related to common cold viruses and easily infects different mammals, including humans, without causing significant disease.
Earlier it was shown by the team that this vaccine platform can completely protect experimental animals from another dangerous coronavirus disease called Middle Eastern Respiratory Syndrome (MERS). The inhaled PIV5 vaccine focusses the mucosal cells that line the nasal passages and airways, which are the chief entry points for most SARS-CoV-2 infections and the site of early virus reproduction.
According to the researchers, the virus produced in these cells can enter deeper into the lungs and other organs in the body, which can lead to more severe illnesses. They further said, the virus made in these cells can be easily shed through exhalation allowing transmission from one infected person to others.
Diseases in ferrets that appeared to block the transmission of COVID-19 from infected ferrets to their unprotected and uninfected cage-mates can be prevented by the vaccines added the researchers.
The study showed that the vaccine produced a localised immune response, involving antibodies and cellular immunity, that completely protected mice from fatal doses of SARS-CoV-2.