Researchers from the Centenary Institute and the University of Sydney have developed a unique nasal vaccination approach that provides significant lung immunity and protection against the SARS-CoV-2 coronavirus.
The findings were reported in the prominent journal Nature Communications. The novel vaccination technique has been successfully tested in mice and has the potential to be a significant tool for improving protection against COVID-19 infection and limiting viral dissemination.
The new vaccine was delivered by simply breathing in through the nose and was made up of the SARS-CoV-2 spike protein and an adjuvant called Pam2Cys (a molecule that helps stimulate a stronger immune response in the body) developed by Professor Richard Payne, NHMRC Investigator in the University of Sydney’s Faculty of Science. It induced significant levels of neutralising antibodies as well as enhanced T-cell responses in the lungs and airways of the mice examined.
Dr Anneliese Ashhurst, lead author of the study and research fellow at the University of Sydney’s Faculty of Medicine and Health and the Centenary Institute, stated that while current COVID-19 vaccines are critical, there are some limitations, including waning immunity after vaccination and infection, as well as the impact of new viral variants evolving.
“Current vaccines against SARS-CoV-2 substantially reduce mortality and severe disease, but protection against infection is less effective. Vaccinated individuals are still catching COVID-19 and can spread the infection, so breakthrough infections are still occurring,” said Dr Ashhurst.
“To stop viral spread and to prevent this virus from mutating we need a new vaccine approach that blocks COVID-19 transmission,” she said.
The novel vaccine was given nasally in the mice trial, making its way through the respiratory system and sticking to the tissues of the nasal cavity, airways, and lungs. High quantities of protective antibodies were found in the airways, as well as enhanced T-cell responses in the lungs, according to testing (T-cells help destroy SARS-CoV-2 infected cells). Notably, none of the vaccinated mice developed COVID-19 infection.
“Our vaccine differs from most current COVID-19 vaccines in that it enables generation of an immune response directly in those areas of the body that are likely to be the first point of contact for the virus – the nose, airway and lungs. This may help explain the vaccine’s effectiveness,” said Dr Ashhurst.
Senior study author, Professor Emeritus Warwick Britton AO, Head of the Centenary Institute’s Tuberculosis Research Program, said that the new vaccine strategy could play a key role in the fight against many diseases.
“Our vaccination findings have shown exciting potential in pre-clinical studies, improving protection against SARS-CoV-2 infection. The approach developed here could help break the COVID-19 infection cycle and will likely influence future coronavirus vaccine related studies,” Professor Britton said.
He added that adapted versions of the new nasal vaccine could also be potentially applied to other viral or bacterial respiratory diseases such as influenza, avian flu, SARS and MERS.