Stopping the Avian Flu Before it Takes Off
As a Vaccine and Treatment Evaluation Unit (VTEU), Cincinnati Children's is one of seven sites testing vaccines that may one day attack the avian flu mid-flight. Researchers in the Division of Infectious Diseases are conducting clinical trials in adults and the elderly on a vaccine that could combat H5N1, the strain of avian influenza that has shown up in more than 200 humans since 1997. "We are looking at the safety and immunogenicity of the vaccine," says Rebecca Brady, MD, an assistant professor who is board certified in adult and pediatric infectious diseases. "We need to find out how the body responds to the vaccine and if the body makes antibodies that respond to the virus."
Drs. David Bernstein and Rebecca Brady review details of a clinical trial they are leading that is testing the H5N1 strain of the avian flu.
Dr. Brady and colleagues currently are testing different doses of the vaccine. Once those results are obtained and analyzed, they will pick the best dose and go through another round of clinical trials to test that dose. "We want to make sure the majority of the group all make high levels of antibodies in response to the vaccine," explains Dr. Brady. "But there is no guarantee that H5N1 is the strain that will cause a pandemic." Therefore, other VTEU sites are testing different strains of the virus.
University research hospitals compete to be named VTEUs, as designated by the National Institutes of Health (NIH). The NIH then uses these sites for vaccine studies. A VTEU since 1994, Cincinnati Children's has conducted vaccine tests for a variety of public health threats, including both smallpox and anthrax.
Many Miles To Go
Even a seasoned marathoner would tire on the long road to developing a safe and effective vaccine worthy of licensing and mass-market distribution. Extensive lab work is followed by animal testing before human trials can begin in small groups of adults. Then bigger populations are tested, with the elderly and children usually being tested last. Dosing and scheduling are looked at in yet more clinical trials to determine when the vaccine should be given and if it can be tolerated in conjunction with other vaccines.
According to David Bernstein, MD, division director, most vaccines don't make it through animal testing. The recent licensing of a rotavirus vaccine was one of the division's proudest moments (see related story, page 10). "It was fairly exceptional when you consider the fact that we had about 100,000 to one odds that it would actually make it to market," he says.
Still, with so much road to travel, Dr. Bernstein asserts that vaccines are critical to keeping people healthy in today's world. "Vaccines are the most cost-effective strategy we have," he says. "Think about the money it takes to transplant an organ versus how many vaccines could be bought and administered with that same amount of money."
In the Meantime
So what if an avian influenza pandemic occurs before we have a licensed vaccine? Dr. Brady explains that some antivirals have been found to work against this flu. She surmises that these drugs, plus quarantining and other containment measures would be put in place to protect against it. "If you look at history, there probably will be another pandemic, but we don't know where it will occur or what the strain will be," Dr. Brady says.
She and Dr. Bernstein feel both the pride and the pressure of working on studies that have a possible worldwide impact. "We are not only affecting children, but adults and elderly as well," Dr. Brady says. Ironically, the greatest reward would be working on a vaccine that would never be needed. She says of the smallpox and anthrax vaccines she studied, "We hope we never have to use them, but we have done testing on them." She hopes the same is true for the avian flu vaccine.
Dr. Brady is assistant professor in the Division of Infectious Diseases. Dr. Bernstein is the Albert Sabin Professor of Pediatrics, director of the division and director of the Gamble Program for Clinical Studies.
