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From Medicineworld.org: Eradication of Polio Nears

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Do You Read All Of Our Cancer Blogs?

Do You Read All Of Blogs?
Do you read all of the blogs published by medicineworld.org? Many of our bloggers are busy keeping you updated on the various health related topics. We publish the following blogs at this time.

Cancer blog: I manage the cancer blog with lots of help and support form other bloggers. Through this cancer blog my friends and I try to bring stories of hope for patients with cancer. The cancer blog often republishes important blog posts from other cancer related blogs at Medicineworld.org. If you are searching for a blog that covers wide variety of cancer topics, this may be the one for you.

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Lung cancer blog: Lung cancer blog is managed by Scott with the help of other bloggers. Through this blog Scott and his friends constantly remind the readers about the dangers of smoking. It's a never-ending struggle against this miserable disease with which a social stigma of smoking is associated.

Colon cancer blog: Colon cancer blog is run by Sue and other bloggers. Sue brings a personal touch to the colon cancer blog since her mother died of colon cancer few years ago. She writes about stories, research news and advances in treatment related to colon cancer.

Prostate cancer blog: Prostate cancer is the most common cancer among American men. American Cancer Society estimates that over 230,000 new cases of prostate cancer occur in the United state every year. This important blog about prostate cancer is run by Mark and other bloggers. This blog brings news, stories, and other personal observations related to prostate cancer.

Medicineworld.org publishes a diabetes watch blog and this blog is run by JoAnn other bloggers. This diabetes watch blog brings you the latest in the field of diabetes. This includes personal stories, advances in diagnosis and treatment, and other observations about diabetes. Improving awareness about diabetes is an important mission of this group.

Janet      

Eradication of Polio Nears


Eradication of Polio Nears
Polio is on track to become only the second disease ever eradicated. In two studies in the Dec. 15 issue of The Journal of Infectious Diseases, now available online, researchers are working to ensure that once it is gone, it stays gone. One study reduces concerns that people whose immune systems were weakened by HIV would re-introduce poliovirus into the community. The other study looks at the how switching forms of vaccine from a live, attenuated vaccine to an inactivated version may affect communities.

Oral polio vaccine (OPV), one of the vaccines instrumental in driving the disease to near-eradication, contains weakened live virus strains. The vaccine is highly effective, easy to administer, relatively inexpensive, and has been used for more than 40 years. Those given the vaccine excrete, or "shed," virus in their stool. There is some concern over the use of OPV, however, because vaccine-derived poliovirus (VDPV) can occasionally cause another form of polio.

Furthermore, in rare cases, immunodeficient persons have shown prolonged shedding of VDPV, which may be transmitted to contacts, thus potentially re-introducing polio into the community. Concerns had been raised that this issue would be a particular challenge in countries with high HIV prevalence.

Karen Hennessey, PhD, MSPH, and his colleagues in Cote d'Ivoire and at the Centers for Disease Control and Prevention examined the duration of shedding of oral poliomyelitis vaccine by individuals with HIV infection.

Dr. Hennessey and his colleagues tested stool specimens at various intervals following vaccination. Out of a total of 419 adults with HIV infection, no poliovirus was isolated from any of the specimens. Because of these results, it is likely that fewer than 1 percent of adults with HIV infection experience prolonged virus shedding when exposed to OPV, "and therefore probably represent minimal risk of re-introducing vaccine virus into the population after poliovirus has been eradicated," the authors concluded.

The alternative to OPV, a live virus vaccine, is an inactivated polio vaccine (IPV). IPV is safer because the inactivated virus in IPV cannot mutate into paralytic VDPV. However, the immune response generated in the digestive tract by IPV was believed to be less potent that that of OPV. Therefore, eventhough those immunized with IPV would be protected from polio, they could still be infected and shed virus, contributing to the spread of the disease.

But all research on the subject had been performed using only one dose of a vaccine that was less potent that the currently used version. Konstantin Chumakov, PhD, and his colleagues at the Food and Drug Administration and various other institutions throughout the United States revisited the issue using two doses of the newer, enhanced vaccine.

They found that two doses of IPV did produce immunity in the digestive tract. The scientists used shedding of virus after therapy with a dose of OPV to measure the immune response. Seventy-five percent of children receiving two doses of IPV, followed by one dose of OPV, shed OPV virus a week later, compared to 92 percent of those receiving just one dose of OPV. After three weeks, 81 percent of the children receiving one OPV dose were still shedding virus, while only 37 percent of those immunized with IPV first were. The amount of virus shed was also lower in those receiving IPV.

However, the mucosal immunity generated by IPV was less than that achieved by OPV. After two doses of OPV, only 22 percent of children given a third dose of OPV were shedding virus after a week. That figure dropped to 5 percent after three weeks.

The scientists concluded that IPV-immunized communities are partially protected from spread of poliovirus. Better protection may be achieved by enhancing IPV further, they said.

However, an accompanying editorial by Harry F. Hull, MD, and Philip D. Minor, MD, at the Minnesota Department of Health and the U.K. National Institute for Biological Standards and Control noted that "the time and expense of developing, testing and securing regulatory approval for a new IPV makes it unlikely that such a vaccine could be available on a timely basis." They also discussed public health, ethical, and financial reasons for stopping vaccination once poliovirus is effectively non-existent, and the risks associated with doing so. Whereas Hull and Minor blame politics and complacency as ultimately being the biggest threats to polio eradication, they conclude that choosing an appropriate vaccination strategy to prevent poliovirus re-introduction is an important and unavoidable task.


Source: Infectious Disease Society of America


Did you know?
Polio is on track to become only the second disease ever eradicated. In two studies in the Dec. 15 issue of The Journal of Infectious Diseases, now available online, researchers are working to ensure that once it is gone, it stays gone. One study reduces concerns that people whose immune systems were weakened by HIV would re-introduce poliovirus into the community. The other study looks at the how switching forms of vaccine from a live, attenuated vaccine to an inactivated version may affect communities.

Medicineworld.org: Eradication of Polio Nears

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