Johns Hopkins Bloomberg School of Public Health researchers say they have developed a method that could make a nasal spray flu vaccine effective for those under two and over 49 – two groups for which the vaccine is not approved.
By studying the weakened flu virus that is the basis for the nasal spray vaccine in cells from human nasal and sinus cavities, the researchers say they have determined that the virus can be weakened (for young children) or strengthened (in older people) enough to create an appropriate immune response in people of all ages.
A report on the findings is published online in the journal Vaccine.
“We think we can use our molecular, rational design approaches to make a better flu vaccine for people who really need it,” says study leader Dr. Andrew Pekosz, associate professor in the Department of Molecular Microbiology and Immunology at Johns Hopkins. “We can do it in a sophisticated and accurate way, not in a blind manner, which is how these vaccines are usually developed.”
Dr. Pekosz says he is particularly excited about being able to produce a better vaccine for older people since flu vaccines are less effective in people as they age and because those over the age of 60 are more likely to get the flu and more likely to suffer serious complications. One reason vaccines using weakened flu virus are not used in the elderly is that they have been exposed to many strains of flu virus over the years and have more antibodies in the nasal tract, which can inhibit the weakened flu virus from infecting and stimulating the immune response necessary to protect against the virus.