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Forum Name: General Discussion
Forum Description: (General discussion regarding the next pandemic)
URL: http://www.avianflutalk.com/forum_posts.asp?TID=37554 Printed Date: April 26 2024 at 3:50am
Topic: Polio SpreadingPosted By: Technophobe
Subject: Polio Spreading
Date Posted: July 02 2018 at 12:42pm
Alarming polio outbreak spreads in Congo, threatening global eradication efforts
By http://www.sciencemag.org/author/leslie-roberts" rel="nofollow - Leslie Roberts
Overshadowed by the Ebola outbreak in the Democratic Republic of the
Congo (DRC), another frightening virus is on the loose in that vast,
chaotic country: polio. Public health experts have worked for months to
stamp out the virus, but it keeps spreading. It has already paralyzed 29
children, and on 21 June a case was reported on the border with Uganda,
far outside the known outbreak zone, heightening fears that the virus
will sweep across Africa. The DRC is “absolutely” the most worrisome
polio outbreak today, says Michel Zaffran, who heads the Global Polio
Eradication Initiative (GPEI) at the World Health Organization (WHO) in
Geneva, Switzerland.
The outbreak also underscores the latest complication on the bumpy
road toward polio eradication. It is caused not by the wild virus
hanging on by a thread in Afghanistan, Pakistan, and perhaps Nigeria,
but by a rare mutant derived from the weakened live virus in the oral
polio vaccine (OPV), which has regained its neurovirulence and the
ability to spread. As OPV campaigns have driven the wild virus to
near-extinction, these circulating vaccine-derived polioviruses (cVDPVs)
have emerged as the greatest threat to polio eradication. If the
outbreaks are not stopped quickly, polio scientists warn, they could
spiral out of control, setting eradication efforts back years.
“There is an urgency” to stopping these vaccine-derived outbreaks,
says epidemiologist Nicholas Grassly of Imperial College London. “It is
so much more important than controlling the wild virus.”
Safe and effective, OPV has long been the
workhorse of the eradication effort. But a feature that makes the
vaccine so powerful can also be a serious downside. For a short time
after vaccination, the weakened live virus can spread from person to
person, boosting immunity even in those who didn’t receive the polio
drops. But in rare instances, in poor countries such as the DRC where
many children have not been vaccinated, the virus can continue
circulating for years, accumulating mutations until it reverts to its
dangerous form. The vast majority of cVDPVs are caused by serotype 2,
one of three variants of the virus.