Scientists look for methods to improve vaccinations for infectious diseases.

2003 JUN 11 - (NewsRx.com & NewsRx.net) -- Oregon Health & Science University (OHSU) researchers are studying new methods to dramatically increase the number of people who can receive vaccinations against smallpox and other deadly diseases.

Currently a significant segment of the U.S. population cannot receive these vaccines because their immune systems are weakened. This condition, called immunosuppression, can be found in many groups, including 30-40 million elderly people in the United States, those battling anxiety or depression, AIDS and cancer patients, and stroke survivors. Such immunosuppressed individuals are often referred to as "vulnerable" populations because they are especially susceptible to infection.

"One of the vulnerable groups that cannot be vaccinated with certain vaccines are those who take steroids," said Mary Stenzel-Poore, PhD, associate professor of molecular microbiology and immunology in the OHSU School of Medicine. "Steroids can also cause immunosuppression. Currently 25-30 million people are taking steroids for various health conditions. That's an extremely large segment of the population at great risk of powerful emerging infectious diseases, such as SARS, or in the case of bioterrorism."

Many vaccines work through purposely infecting the patient with a mild, related form of the disease. For example, in the case of smallpox, the virus vaccinia is the active ingredient. The related virus causes the body to produce protective antibodies and specialized white blood cells, called T-cells, that can search for and destroy cells infected with the more serious form of the disease (i.e., smallpox itself).

In most patients, vaccines result in little to no illness whatsoever. However, patients with compromised immune systems may face serious illness or death because their bodies can't fight off the infection caused by the vaccine. Even when ...