Scientists are designing a way to make a nasal spray flu vaccine safer for infants under the age of two. The work is still in early stages but offers big hopes for a flu vaccine easier to be administered to toddlers and offering better protection to the most vulnerable.
FluMist, the currently available nasal spray vaccine, is made from live flu virus dampened down. Up to date, FluMist is only approved for use in people two through 49 years old. Older adults, asthmatics and infants are not eligible for the vaccine.
The traditional shot version of the flu vaccine includes killed or inactivated virus. Because in a nasal spray vaccine the virus is live, it creates a more robust immune response because it activates multiple components of the immune system.
The delivery of the nasal spray vaccine is made via a spray into each nostril. Then, the flu vaccine moves through the respiratory tract from the nose to the lungs. Inflammation in response to the virus could appear if the vaccine virus enters the lungs.
Because in clinical trials the FluMist vaccine was associated with wheezing in infants, the vaccine is not approved for use in children under the age of 2.
According to Futurity, researchers are now working on a vaccine similar to FluMist. Tests are currently made on mice. The research team is using molecular genetics in order to alter the vaccine virus and make it replicates only in the nose and not in the lungs. This will help avoiding that the vaccine causes wheezing in toddlers.
Very young children have narrow airways that can become easily constricted. The risk of wheezing could be eliminated if the vaccine virus stays only in the nose. This way the nasal spray flu vaccine could become a safer option for infants, as well as people suffering of asthma.
According to Andrew Cox, lead author of the study, vice dean for research and chair of the microbiology and immunology department at the University of Rochester and a graduate student in the laboratory of Stephen Dewhurst, this is the first time when scientists try to tweak a vaccine virus like this. The research paper is published in the Journal of Virology.
