Post Polio is a condition that affects up to 8% of persons who survive paralytic polio; can develop as late as, 30, 40 years after the initial recovery; symptoms vary from mild weakness to severe fatigue and disability .
The world is launching what could be the last assault on polio – and it will require the biggest roll-out of a vaccine ever attempted.
All 194 countries that belong to the World Health Organization will next week initiate a new plan for juggling different polio vaccines on a global scale that could finally eradicate the crippling virus.
The stakes are high, says Oliver Rosenbauer of the WHO. With most of the world polio-free, global immunity is spotty. Models predict that if the eradication drive is abandoned while the virus persists, the rebound could cause 200,000 cases of paralysis a year for 10 years. But without a clear end to the campaign in sight, countries could abandon the effort.
The original deadline of eliminating polio by 2000 has repeatedly slipped, with the virus clinging on in India, Nigeria, Afghanistan and Pakistan. However, there have been no cases in India since 2011, cases in the other three are at an all-time low, and four other reinvaded countries are all but clear again.
But problems loom. People who reject vaccination on religious or political grounds have murdered 19 vaccinators in Pakistan and Nigeria. And aprediction in 2000 has come true: the vaccine has become its own enemy.
Until now, the eradication drive has only used an oral vaccine containing weakened live virus, as it is cheap, easy to give and extremely effective. But the vaccine viruses can sometimes revert to causing disease – and spread. In 2012, for the first time, more countries reported cases of the disease caused by vaccine-derived polio viruses (cVDPV) than wild virus.
The original plan was for every country to stop using live vaccine simultaneously when wild polio disappeared, switching instead to a killed polio vaccine that would protect children as any lingering cVDPV died out. But if wild polio or cVDPV return after that, countries will need intense surveillance to spot it and live vaccine to contain the spread, fast. Both exist during the eradication drive, says Bruce Aylward, head of WHO's polio programme; but neither will exist afterwards, as countries refocus on other threats and companies stop making live vaccine.
The new plan is to switch to killed vaccine before eradication is over. The WHO predicts that wild virus will be largely gone by 2015.
At that point the WHO wants the 140 countries at most risk of a polio resurgence to start giving killed vaccine. But this may not be enough to keep resurgence at bay. So they will also use a live vaccine, but one that is effective against only two of polio's three strains. Virtually all cVDPV is type 2, which was eradicated in 1999.
By using live polio vaccine containing only types 1 and 3, countries can maintain immunity to any persisting wild polio, while cutting off the source of cVDPV.
It must be done all at once, however, because if one country stops using type 2 live vaccine, while a neighbour continues, the first is at risk from type 2 cVDPV. That means, says Aylward, that killed vaccine "will have to be introduced in 140 countries within a one to two-month time window. Nothing like that has ever been done before."
Global scientists declare support for new plan to create a polio-free world by 2018 Thursday, April 11, 2013
A three month old baby is given two drops of polio vaccination in Jalalabad
UNICEF / Knott
11 April, 2013 - More than 400 scientists from around the world, including Nobel laureates, public health school deans and other leading health experts, added their names to the Scientific Declaration on Polio Eradication [pdf] today, asserting that polio eradication is possible and expressing their confidence in a new plan to create a polio-free world by 2018.
With just 223 cases reported in 2012, compared to more than 350,000 in 1988, the world has a narrow window of opportunity to end this disease. The signatories to the declaration expressed their support for the Global Polio Eradication Initiative’s new Polio Eradication and Endgame Strategic Plan 2013-2018, calling on the global community to make the most of the current opportunity to end polio and fully fund the new plan.
The declaration, timed to coincide with the 58th anniversary of the announcement of the first polio vaccine, comes just two weeks before the Global Vaccine Summit – to be held in Abu Dhabi on 24-25 April. The Polio Eradication and Endgame Strategic Plan 2013-2018 will be shared with world leaders at the summit.