Lung treatment breathes new life into flu vaccines

2019-03-01 10:12:07

By Reuters and New Scientist Delivering flu vaccines straight into the lungs, instead of through routine injections, could trigger a far stronger immune response, a study finds. The world is expected to be extremely short of vaccines in the event of a flu pandemic, so the search for the best way to deliver vaccines is important as this could reduce the quantity administered in each dose. The Australian study shows that lower doses of a seasonal flu vaccine delivered into the lungs of sheep gave better protection against flu than a higher standard dose that was injected into another group of sheep. “Our results suggest that delivery by the lung may allow a much lower dose to be used in the influenza vaccine, while inducing equivalent or perhaps even improved protection,” says Philip Sutton of the Centre for Animal Biotechnology at the University of Melbourne, one of the authors of the study. “This would mean more people would quickly be able to receive the vaccine.” The scientists delivered various doses of flu vaccines into the lungs of three groups of sheep. A fourth group of sheep was injected with standard 15-microgram flu vaccines. Sutton says that the lung delivery method produced roughly 1000 times higher levels of antibodies in the lung than injection. That is significant because influenza virus attacks the lungs directly. “The antibodies produced in the blood and lung were able to block the ability of the virus to stick to the receptor it uses to infect cells, demonstrating they would be effective against infection,” Sutton says. The generation of such huge amounts of antibodies in the lungs is especially important in the case of influenza, because flu is spread mainly through sneezing and coughing. “The generation of functional antibodies in the lung could potentially help reduce the spread of the infection by neutralising the virus before it can be breathed out by an infected person,” adds Sutton. One drawback is that the vaccine is currently fed into the lung in an uncomfortable procedure using a tube called a bronchoscope. Sutton noted that the team would need to find better ways to deliver vaccine directly into the lungs for the technique to be acceptable for humans. Journal reference: Mucosal Immunology (DOI: 10.1038/mi.2008.59) Bird Flu – Learn more about the flu pandemic that could kill millions in our continually updated special report. More on these topics: