Tajikistan polio outbreak could spread, Canadian Medical Association warns

From The Canadian Press:

TORONTO - A large polio outbreak in Tajikistan — Europe's first in years — has the potential to further spread the dangerous virus to other regions of the world, the Canadian Medical Association Journal warned June 23.

Top editors of the journal suggested the outbreak, the largest since 2005 in a country where polio is not endemic, serves as a reminder that until polio is eradicated, the risk of renewed spread remains.

"In all countries certified as polio-free, including Canada, the Tajikistan outbreak should be clanging alarm bells," editor-in-chief Dr. Paul Hebert and Dr. Noni MacDonald, section editor for public health, wrote in the editorial which was published online.

"The key message here is pretty straightforward. You can't let your guard down on this one because . . . if you do, pop! There it goes. Another outbreak," Hebert said in an interview.

Others questioned whether the risk to Canada is as grave as Hebert and MacDonald suggested, but agreed with the overall principle that no country is safe from polio while the virus continues to spread in parts of the globe.

"It clearly is a wake up call," said Dr. John Spika, director general of the Public Health Agency of Canada's centre for immunization and respiratory infectious diseases.

Spika said Canadian polio vaccine coverage rates are generally high enough to prevent spread, but he acknowledged there are pockets of children who aren't vaccinated, either because of religious reasons or because their parents subscribe to anti-vaccine sentiments.

"The incredible success of immunization programs is leading to some complacency," he said. "And therefore our challenge is really how do we continue to maintain high coverage in the face of that very low perceived risk of disease and growing perceived risk that there's injury following vaccination?"

The Tajikistan outbreak is the latest in a string of setbacks for the global polio eradication initiative, the 22-year-old campaign aimed at permanently stopping the spread of the disease.

The campaign, jointly run by the World Health Organization, Rotary International, the U.S. Centers for Disease Control and UNICEF, has to date spent $8 billion trying to achieve the goal.

Only four countries remain on the list of nations that have never interrupted spread of polio — Nigeria, India, Pakistan and Afghanistan. And after years of setbacks, enormous progress has been made in these countries this year.

But then in April polio was found in Tajikistan. Analysis of the viruses show the outbreak was the product of an importation from northern India.

As of Wednesday, there have been 275 confirmed cases in the outbreak and lab results are pending on about 300 more suspected cases, said Dr. Bruce Aylward, the Canadian who heads WHO's polio eradication team.

"This is a big one, that's for sure," he said of the outbreak in an interview from Geneva.

The last outbreak of this size in a previously polio-free country was in Yemen in 2005, when 478 cases were reported, he said.

"Outbreaks of this size are very rare now. You see them in India and Nigeria. But outside of that, you never see an outbreak this big anymore. Very, very rare."

Aylward said there are signs the outbreak is coming under control. There have been no new cases reported in the past 10 days. But control doesn't count in polio, he said; stopping transmission has to be the goal.

And that's the message of the editorial Aylward wanted to highlight.

Given the tremendous cost of the effort and the fact that the virus continues to foil the Herculean efforts to wipe it out, some scientists have questioned whether eradication is achievable. It would be better, some suggest, to try to aim for controlling polio at low levels and use the money devoted to eradication for broader public health purposes.

Aylward said the Tajikistan outbreak shows the shortcomings of that argument. The world is currently spending $800 million a year to keep polio to fewer than 1,000 cases a year, he said. "(But) it's not going to stay there if you don't finish. Those funds are going to disappear."

He likened the continued spread of polio viruses to sparks from a fire. "They don't always catch. But then when it catches, it can explode."

And pockets of unvaccinated individuals in Canada or other developed countries could provide those sparks an opportunity to ignite, Aylward said — though he, like Spika, believes polio vaccine coverage rates are high enough here that a large outbreak is unlikely.

"It's harder for the spark to catch," said Aylward. "But the bigger point they're making — that look, we are still at risk of the disease — is very, very true."