An experimental influenza vaccine delivered through a nasal spray has worked extremely well in a trial among healthy young children and “could have a significant impact on public health,” the National Institutes of Health reported Monday.
The vaccine not only induces a broader immunity than current vaccines, but it also is far easier to produce in large quantities, and easier to administer. That means it could be made available to many more people, potentially reducing transmission of the virus.
“The initial results from this trial are very exciting,” said Dr. Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases.
Each year, between 35 million and 50 million Americans contract flu, and more than 20,000 people die. The economic costs of influenza can be high: A severe epidemic including more than 172,000 hospitalizations would cost at least $12 billion in medical expenses and lost productivity.
The experimental vaccine was developed and refined over several decades by researchers at the University of Michigan School of Public Health, the infectious diseases institute, and Aviron, a biopharmaceutical company in Mountain View, Calif.
Pending FDA approval, the company intends to make the vaccine available by prescription in the United States for vaccination campaigns in the fall of 1999.
Administered through tiny squirts of spray in each nostril, the vaccine induces a broader immunity than injected vaccines because it enters the body through the mucous membranes of the nose and follows the natural route of an infection, said John La Montagne, director of the institute’s division of microbiology and infectious diseases.
Perhaps the greatest effect would be on children, who have a flu “attack” rate of two to 10 times that of adults. By age 5, most children already will have suffered two or three bouts.
However, the flu does not pose a serious health risk to children, so they are not routinely given the current vaccines, which are in short supply. Instead, those vaccines are restricted to groups with a high flu mortality rate, such as the elderly and those with diabetes, and other health conditions.
But because children suffer so many bouts of the flu, they are a major conduit of infection to the entire population. Public health officials believe that preventing flu in kids could play a big role in reducing overall transmission and incidence of the disease.
Researchers hope that once the nasal vaccine is licensed it ultimately can be administered to children and healthy adults, and given along with the injectable vaccine to high-risk individuals.
Like the current vaccine, the nasal type would have to be administered annually and would be changed every year to conform to the strains of flu that are circulating.