Vaccine that Lasts for "Virus of Terror"
Protection from smallpox is good for 30 years, say experts
KEEPS GOING, AND GOING
WASHINGTON
Contrary to popular belief, the smallpox vaccine can last up to 30 years or longer, according to a US study.
"Given the general belief that the vaccinations lasted only seven to 10 years, we were surprised how durable the CTL responses were," said study co-author Jeffrey Frelinger, professor and chairman of microbiology and immunology in the School of Medicine. Frelinger and his postdoctoral researcher Lawal Garba from the University of North Carolina at Chapel Hill noted "two observations are obvious: vaccine induces a robust CD8 T lymphocyte response in healthy individuals and the response is of long duration."
Their tests showed that people who had been immunized decades earlier still reacted to the vaccine by producing interferon-gamma, proteins produced by T cells when responding to an attack on the immune system.
"It is striking that the loss of reactivity over more than 35 years is very low in individuals with a remote history of vaccination compared with recently vaccinated individuals," they said. A healthy 4.8 percent of CD8 cells in people vaccinated more than 35 years ago responded to the vaccine, versus 6.5 percent in people recently vaccinated.
According to Frelinger, the discovery of the long-lasting benefits of the vaccine could influence US smallpox immunization strategies envisioned by medical experts in case of a smallpox bioterrorist attack. "If you had a limited supply of vaccine, I think you'd want to target predominantly previously unvaccinated individuals," he said, underlining the importance of immunizing people who have never been immunized against the disease, which was declared eradicated in 1980.
THEY KILL IT, THEY MAKE IT
WASHINGTON
Researchers using mail-order materials and a genetic code have synthesized the poliomyelitis virus in the laboratory, raising fears that terrorists could do the same.
The synthetic virus was virtually indistinguishable from the original, and first paralyzed-then killed-mice injected with it, according to a study at the State University of New York at Stony Brook and published in the journal Science.
"The potential for virus synthesis is an additional important factor for consideration in designing the closing strategies of the poliovirus eradication campaign," researcher Eckard Wimmer said. He warned that a synthetic poliovirus would be valuable as a bioweapon if mass vaccination stops and immunity to the disease is lost. Information on virus genomes is easily accessible online, he said.
"You open the Internet and lift out a sequence and go to work and make a virus without ever having seen the virus in your laboratory," he said. "This work is very important to put society on alert. This is an inherent danger in biochemistry and scientific research. Society has to deal with it. It won't go away if we close our eyes."
In an accompanying article, Science said biologists disagreed over how easy it would be to create bioweapons or synthesize bulkier viruses such as smallpox. While an epidemic of poliomyelitis is a frightening prospect, scientists believe terrorists might focus their efforts on deadlier viruses, such as smallpox.
Wimmer noted, however, that the smallpox virus is much bigger and more complex than the poliovirus and would require more work to synthesize. "It is much more difficult to do currently," he added, "but with progress in science and technology it will be possible in 10 to 15 years to make smallpox."
Aside from the danger a synthetic poliovirus would pose in criminal hands, it also could lead to benefits for medicine, such as rebuilding other viruses in a weakened form to help devise new vaccine, researchers said.
ALSO FOR ADULTS
WASHINGTON
US researchers have found that inoculating adults with a pediatric chicken pox vaccine can help prevent the adult form of the disease, shingles.
Scientists studied the effects of administering a heat-inactivated form of the vaccine to cancer patients at particular risk of developing shingles. The results presented by the researchers at the University of Stanford Medical Center showed that 13 percent of the 53 patients suffering from lymphoma who were vaccinated developed shingles after a blood transplant to help fight the cancer, versus 30 percent of the 56 study participants who were not vaccinated. The vaccine also could prove effective in preventing shingles in older patients in good health.
Vaccines normally use a weakened strand of a disease, but in this case the study was done with cancer patients and researchers did not want to take any chances with patients who already have severely weakened immune systems. The inactivated form used in the inoculations produced the same effect in the patients' immune systems as a normal vaccine would in a healthy person.
STOPPING MAD COW DISEASE
WASHINGTON
A vaccine has been developed that delayed the onset of a brain disease in mice similar to mad cow disease, according to researchers at the New York University medical school. They were the first to show a vaccine can delay symptoms in a natural model of prion disease in mice.
Prions are proteins that scientists believe cause a group of fatal brain diseases, including mad cow disease. "We are currently making alterations in the prion protein to reduce the likelihood of toxicity while maintaining a therapeutic effect," said Einar Sigurdsson, NYU professor who worked on the study. He said the vaccine used was based on the normal sequence of amino acids for the prion protein, which could be toxic when administered to a human.
Many researchers are convinced these types of degenerative brain diseases, known as spongiform encephalopathies, are transmitted by prions, which can act as an infectious agent. Doctors still don't know, though, exactly how these proteins destroy cerebral tissue, leading to insanity.
These diseases are characterized by progressive dementia and abnormal limb movements and affect people as well as animals. Prions cause mad cow disease in cattle and scrapie in sheep. Humans can get a number of different prion diseases, including variant Creutzfeldt-Jakob disease.
The vaccine tested didn't protect the mice from infection, but it did induce an immune response in the form of antibodies in the mice. A higher level of antibodies was detected in the mice that resisted the disease the longest, proving that antibodies can protect against the illness, according to the report.
"This is a step in the right direction, and we are really encouraged because the experiments suggest that the production of antibodies is critical to a therapeutic response. Obviously, we would prefer to prevent infection altogether," said study co-author Thomas Wisniewski.
TINY NEEDLE
TOKYO
Japanese researchers have developed a microscopic needle modeled on a mosquito bite that could drastically reduce the pain of taking blood. The needle is part of a wearable medical device that would enable users to take their own blood, test it, and send the result to a remote doctor over the Internet, said Eiji Nakamachi, an engineer at the Osaka Institute of Technology.
Nakamachi aims to make the postcard-size device a marketable "wristwatch size" within two and a half years. The external diameter of the hollow, titanium-made needle measures 60 microns (60 millionths of one meter) and the inner diameter is 25 microns, compared with 30 to 40 microns for the mosquito's blood-sucking proboscis, or section it uses to extract the blood, he said.
The needle, one-tenth the size of the currently used products, could "greatly reduce the pain," he said, adding mosquitoes inject some painkilling substance to suck blood. A spring that extends when heated inserts the needle into the skin, and a miniature electric pump sucks up the minute blood sample.
"If we reverse the pump, [the needle] could be used to deliver drugs," Nakamachi said.
NOT JUST FOR SEX
PARIS
Viagra shows good potential for helping people with a potentially life-threatening lung condition. Doctors at Giessen University Hospital in Germany tested Viagra and two other blood vessel dilators on 16 patients who suffered from chronic lung fibrosis and pulmonary hypertension.
The patients, whose genders were not given, were given either Viagra, inhalation of nitric oxide, or an intravenously administered drug called epoprostenol.
Viagra was as effective as the others in helping to oxygenate the lungs and in lowering the blood pressure in the pulmonary artery, but offered the advantage of being an oral treatment. Neither were there any "adverse effects" from taking the Viagra, including unwanted erections among men, the authors said.
"The unique profile of sildenafil... suggests that the drug is a promising candidate for long-term treatment of secondary pulmonary hypertension in lung fibrosis."
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