Polio article-Washington Post
Following is a comprehensive article published in the Washington Post
dated 12/26/05. It covers the participation of the WHO, UNICEF and
Rotary International in the struggle to eradicate polio. All in all, a
very good article.

Clyde Edmonds PDG
D5470, Colorado, USA

Global Polio Largely Fading - Stronger Vaccine Is Playing Key Role
By David BrownWashington Post Staff Writer
Monday, December 26, 2005; Page A01
The 17-year effort to eradicate polio from the world appears to be back
on track after nearly unraveling in the past three years.
A new strategy of using a vaccine targeting the dominant strain of the
virus appears to have eliminated polio from Egypt, one of six countries
where it was freely circulating. That approach is on the verge of doing
the same in India. Twenty-five years ago, India had 200,000 cases of
paralytic polio a year. A decade ago, it was still seeing 75,000 cases
annually. Through November this year, it recorded 52.
Such dramatic successes, many the result of a more potent formulation of
polio vaccine, have once again made eradication of the paralyzing viral
disease a realistic goal. Only one human disease -- smallpox -- has ever
been wiped out, and that was almost three decades ago.
Intensive immunization campaigns targeting tens of millions of children
in Africa have suppressed polio transmission in countries where it
reappeared after the continent's most populous nation, Nigeria, halted
universal polio vaccination in 2003.
The end of 2005 had been the latest deadline for polio eradication. The
initiative, started in 1988, had a polio-free world by 2000 as its goal.
No new deadline has been set, and success may depend, in part, on
raising $200 million for more vaccination campaigns.
Nevertheless, the organizers and those funding the eradication
initiative are more confident.
"I don't think there's any question that it's going to succeed. The
question is how long," said William T. Sergeant, a Rotary International
official. "The countries that were reinfected -- they were places where
we had stopped polio before, and we can stop it again."
A civic club with 33,000 chapters worldwide, Rotary is a co-leader of
the eradication campaign, to which it has contributed $600 million and
tens of thousands of volunteers.
"The risk now is Nigeria -- and losing the commitment in other
countries. But we're confident now that Nigeria will get the job done,"
said David L. Heymann, chief of the polio eradication program at the
World Health Organization, which is directing the initiative.
The new "monovalent" vaccine appears to have been close to a magic
bullet in boosting immunity to polio in a half-dozen areas of extremely
high population density.
"This is the big development, without a doubt," said R. Bruce Aylward, a
Canadian physician and WHO's chief eradication strategist.
The effort to eliminate polio has taken longer and proved harder than
the eradication of smallpox, which took 10 years and ended in 1978. One
of the main reasons is that most polio infections are not apparent,
while smallpox causes a dramatic rash that makes identifying victims
fairly easy.
Although polio virus does its damage in the spinal cord, it infects the
body through the intestine and spreads most easily in crowded
populations with poor sanitation.
In only 1 in 200 infections does it cause paralysis. In other cases, it
produces only fever and diarrhea, or no symptoms. Consequently, polio
virus can be carried "silently" into a polio-free population and spread
before it is recognized.
That is what happened when the Islamic states of northern Nigeria
stopped immunizing children in 2003 because of rumors that the oral
vaccine caused sterility and was part of a Western campaign against Muslims.
Between January 2003 and July 2005, 18 polio-free countries were
reinfected with virus that originated in northern Nigeria.
Analysis of the poliovirus genes -- which accumulate mutations at a
steady, known rate -- allowed scientists to trace the route, and even
the timing, of the microbe's spread.
Work done at the Centers for Disease Control and Prevention by Olen M.
Kew and Mark A. Pallansch showed that virus from northern Nigeria was
carried into Chad and several neighboring countries in 2003. From Chad
one strain moved to Sudan in late 2003 or early 2004, and from there to
Saudi Arabia. From Saudi Arabia it was carried to Indonesia, where on
March 13 this year, polio was diagnosed in an infant boy in West Java --
the first Indonesian case since 1995.
Reinfection occurred because these countries had not maintained adequate
immunization rates in young children.
During the same period, three other polio-free countries -- Angola,
Lebanon and Nepal -- were reinfected with virus that originated in
northern India.
In all these countries -- and in northern Nigeria, where politicians and
clerics now support polio vaccination -- intensive immunization
campaigns have resumed.
Last month, WHO experts confirmed that 10 reinfected African countries
-- Benin, Burkina Faso, Cameroon, Central African Republic, Chad, Ivory
Coast, Ghana, Guinea, Mali and Togo -- have reported no cases since late
June. That strongly suggests virus transmission has been stopped.
The trans-Africa outbreak had many arresting features -- post-9/11
suspicions of the West in Muslim regions, political jockeying in Nigeria
and a humanitarian disaster in Sudan that accelerated the spread of the
disease.
"What the world wasn't looking at was what was happening in Egypt and
India," Aylward said recently in his office in Geneva.
Vaccination campaigns were being run every few months in those
countries. They were reaching 90 to 95 percent of children younger than
5. Yet polio kept circulating.
"This was a much bigger risk than Nigeria because we had a potentially
fatal flaw in the program," Aylward said.
The solution came when Aylward and his colleagues realized that --
ironically -- they would get better results with a much simpler version
of the vaccine.
There are three types of polio virus -- 1, 2 and 3 -- that differ
slightly. No type 2 virus has been detected since September 1999; it
appears to be eradicated. Type 3 is disappearing fast; it occurs only in
Nigeria, Niger, northern India and Afghanistan.
Oral polio vaccine contains weakened strains of all three. That would
not seem to be a problem -- except it turns out it is.
A dose of oral vaccine -- two drops -- contains about 1 million type 1
viruses, and about 100,000 type 2 and type 3 viruses. In the human
intestine, these viruses compete with one another in producing
"protective immunity" against the virus.
After one dose of oral vaccine, only about 25 percent of babies were
protected against type 1 polio virus. That rises to more than 90 percent
-- but only after multiple doses. In two Indian states where polio is
endemic -- Uttar Pradesh and Bihar -- nearly 750,000 babies are born
each month. That results in a pool of unvaccinated "susceptibles" that
constantly numbers in the millions.
Studies showed, however, that giving a vaccine containing only type 1
virus to infants produced immunity in 80 percent after a single dose.
Armed with that understanding, WHO found vaccine makers willing to make
a monovalent type 1 vaccine, and in November 2004 it ordered 50 million
doses.
In six months, the reformulated vaccine got through the process of
testing, approval and licensing by regulatory agencies in France, India
and Belgium, where it is made.
"No quality controls were skipped. Everybody just gave us their highest
attention," said Shanelle Hall of the supply division of UNICEF, the
agency that provides most of the vaccine.
Since the vaccine went into use in Egypt this spring, polio has
disappeared there. UNICEF has ordered 600 million doses and plans to use
it throughout much of Africa.
Next year, India may be free of polio. One former hotbed -- Bombay --
already is.
Since April, no polio virus has been detected in that city's sewage.
That is indirect evidence the virus is no longer carried by any of its
12.7 million residents -- undoubtedly for the first time in history.