Double vaccines ‘could hasten the end of polio’

This is an interesting piece on the current global fight against Polio, written by James Gallagher Health editor, BBC News website.

Using both types of polio vaccine could speed up efforts to free the world of the disease, research suggests.
The oral vaccine is leading the fight to eradicate polio, but trials in India show an additional injection of inactivated virus boosts immunity.
The World Health Organization said the findings, published in the journal Science, were “truly historic”.
The disease, which is spread through contaminated faeces, can cause paralysis and even death.
Fighting polio has been one of the biggest success stories in global health.
In 1988, there were 350,000 cases of polio in more than 125 countries.
The disease is now widespread in just three countries – Nigeria, Afghanistan and Pakistan – and cases have fallen by more than 99%.

Vaccines
Two drops of the oral vaccine, which contains a weakened polio virus, is the preferred tool in eradication efforts because it is cheap and gives resistance in the digestive tract to lower transmission of the virus.
The injected vaccine works largely in the bloodstream.
“But the oral vaccine is less effective in exactly those places we’d like it to work,” one of the researchers, Prof Nicholas Grassly, of Imperial College London, told the BBC.
It is thought other infections may interfere with the vaccine.
The solution has been multiple vaccination. As part of India’s successful eradication campaign, some children received 30 doses by the age of five.
Trials in India showed using an injection of inactivated virus as a booster jab was more effective than multiple drops.
However, the biggest challenge in banishing the disease for good is not the choice of vaccine, but getting to children in conflict-ridden areas.
The security issues can be huge and vaccination programmes are even used as a political weapon.
In 2012, the Taliban said vaccinations in the North and South Waziristan regions of Pakistan were banned until the US ended drone strikes.
Prof Grassly argues: “If you have limited access, you want the biggest return. If you can go in with inactivated and oral polio vaccine, you will achieve a lot more than if you just have brief access with oral polio vaccine.”
The double-vaccine approach is already being used in parts of Nigeria and will soon be introduced into Pakistan also.
Dr Bruce Aylward, the World Health Organization assistant director general for polio, said: “The results of this study are truly historic in the context of global polio eradication.
“This study has revolutionised our understanding of inactivated polio vaccine and how to use it in the global eradication effort to ensure children receive the best and quickest protection possible from this disease.”

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Polio Eradication: “a Global Public Health Emergency”!

The 65th WHA has declared Polio eradication a “Global Public Health Emergency” the statement is weighty, Here’s a quick summary of the implications of the World Health Assembly’s Resolution:
1.) Polio eradication has reached a tipping point. While the world is more than 99% of the way towards eradicating the disease, a funding shortfall has already caused vaccination activities to have been cut back – putting vulnerable communities at risk from the disease.
2.) If we fail to eradicate polio, the consequences will be disastrous. Research has shown that the world would soon see more than 200,000 cases a year. This is why the continued transmission of polio is now an emergency.
3.) This resolution gives countries greater powers to combat polio. For instance, they can choose to require travellers to and from polio-infected countries to be vaccinated against polio. Polio-infected countries have been urged to draw up emergency action plans for combating the virus.
4.) The resolution also calls for the World Health Organization’s 194 Member States to fully fund the Global Polio Eradication Initiative.
Declaring polio an emergency for global public health is an important step forward, yet we will only see the end of polio if the funding gap is filled. This is why we are asking world leaders to go beyond words and ensure that the Global Polio Eradication Initiative is fully funded.
We are about the end of the Q2 2012, the number WPVs are 30 already, Unless our politicians and other leadership are serious, only then perhaps, the target of 2012 is already a mirage.

Losing Polio!

I came across this very interesting piece from US Foreign Policy site (by Laurie Garrett) titled: Losing Polio.
“As cries of concern from New Delhi grew louder, earlier this year the WHO gave Islamabad a stern warning: Stop polio or face global health travel restrictions, which would be economically crippling. After two years of mishaps in its bungled immunization efforts, Pakistan’s health leadership went overboard, stopping cars at tollbooths and dropping polio vaccine into every child passenger’s mouth. By April, local polio trackers sent numbers to Geneva that the WHO interpreted as hopeful signs that the disease was finally coming under control. But recently, Pakistan’s chief health commissioner Tariq Pirzada revealed that the numbers were faked by overzealous officials eager to please the WHO. In truth, rural immunization rates remain appalling.

The call for polio eradication goes back decades, and was initially backed by millions of members of the Rotary Club International, which raised much of the money used to eliminate the disease from the Americas, nearly all of Africa, and Southeast Asia. More recently, philanthropist Bill Gates jumped into the fray, donating billions of dollars to the effort. Combined with the WHO, UNICEF, and other organizations, these players eliminated 99 percent of the global burden of the disease, including cases of permanent paralysis caused by the crippling virus and deaths. But in mid-May, U.N. Secretary-General Ban Ki-Moon warned that the great achievements to date could collapse if polio efforts fail in Afghanistan, Nigeria, and Pakistan. 

“There is a looming danger that we could fall victim to our own success,” he warned. “Here’s why: The world is now populated by a generation that for the most part has never been exposed to polio. Additionally, many in this generation have been inadequately vaccinated. When the virus strikes under those conditions, the impact can be devastating. We saw that in the Republic of Congo and elsewhere in Africa in 2010, when an outbreak killed half of all who contracted the virus.”

Eradication is tenuous. Since the early 1960s it has been known that the polio virus can be carried by higher primate species, including monkeys, chimpanzees, and gorillas. In the laboratory it is also possible to infect rodent and chicken cells with the virus, though there is no evidence of those species carrying polio in nature. Nevertheless,  unlike smallpox — the only human pathogen ever eradicated — polio isn’t merely a Homo sapiens germ.

The virus, moreover, enters the human body in multiple ways, and after vaccination may continue to reside in the gastrointestinal (GI) tracts of infected individuals. Back in the 1950s, when scientists Jonas Salk and Albert Sabin competed to be the first to invent a vaccine, Salk created an injectable version that eliminated the virus from the individual’s bloodstream, built up antibodies, and completely protected children from the disease. But Sabin showed that those children could still harbor viruses (harmlessly to themselves) in their GI tracts, and shed infectious microbes in their faeces. Thus, Sabin said, oral vaccination was preferable, as it cleansed the intestines and built up local cellular immunity that protected not only the vaccinated individual, but the general public health by eliminating faecal passage of virus into water supplies, food, and untreated sewage systems.

Broadly speaking, this conflict between oral versus injected vaccination, public versus individual protection, and lifelong immunity versus temporary was at the heart of ongoing technical disputes regarding how best to target the disease, and whether eradication is even possible. While oral vaccination is easier than giving shots, its immunization impact is weaker and wanes with time — even fairly recently immunized Indian children are showing signs of lost protection. Overcoming this requires giving a child as many as seven doses of polio vaccine droplets over a period of months — a monumental logistics feat for poor countries, particularly in rural areas.

After years of struggle, India succeeded in vanquishing polio only when it switched its vaccine strategy to radically decrease the need for boosters. Instead of using an oral formulation that counters all three strains of polio viruses at the same time — but weakly — in 2009, India introduced a stronger vaccine that targets only the dominant two polio strains. The new vaccine gave children a 30 percent more powerful initial immune response, meaning that even without boosters, many Indian kids were protected. The impact was immediately felt, even in the poorest parts of the country. But this strategy may have rendered the children only temporarily protected, accounting for India’s fears of Pakistani vaccination failure. Yet the government should also be concerned about its own population’s anti-vaccine movement, which has reached middle-class India, where some parents decline immunization under false grounds that it would contribute to autism.

The world is very close to victory, but the remaining challenges are more cultural and political than scientific. Last year, a team of experts was deployed by the U.S. Agency for International Development to Afghanistan, Nigeria, and Pakistan to ask  local villagers what the polio eradication effort was doing wrong. In village after village, they got the same astonishingly obvious answer: Stop sending teams of men to vaccinate our children. Even a rudimentary understanding of conservative Muslim culture should have taught the would-be disease vanquishers that under Islam a woman may not allow an unrelated male into her home without her husband’s presence, nor should she allow the well-meaning gentleman to touch her female children. In all too many cases, vaccine failure boiled down to finally sending all-female health teams to Muslim-dominated villages.

Though the WHO says the final eradication effort is shy $1 billion, money is less likely to decide the fate of the great polio elimination campaign than governance, politics, and culture in three hotbed nations. Which is why the CIA’s use of a phony vaccine campaign is so infuriating to health officials. It undermined the faith that many Muslims in vulnerable countries place in Western-inspired immunization and medicine. And with millions of children in India and some other countries now experiencing waning immunity, time is decidedly against us. If wild polio hasn’t been eliminated from the final three countries by the end of 2012, the virus could well resurge in sites of alleged eradication, all over the world. And thousands will suffer.”

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An overview

Polio, a highly infectious disease caused by a virus, has no cure but can only be prevented (life-long) using a polio vaccine given couple of times to under-five children. Infection is by faeco-oral route and gets multiplied in the intestine finally invading the nervous system which resultant paralysis within hours.

Although symptoms are protean in nature, they include fever, fatigue, headache, vomiting, neck stiffness and pain in the limbs. In every 1 in 200 infected cases, irreversible paralysis (usually affecting the legs) ensues. In those paralysed, there is a mortality rate of about 5-10 per cent especially when the diseases affected their breathing muscles.

Significant achievements have been recorded due to the intensified efforts to ensure global eradication of the disease. The global case load of the disease have decreased by over 99 per cent from an estimated 350,000 cases in more than 125 endemic countries in 1998 to 1349 reported cases in 2010. Furthermore, case numbers of wild polio virus type 3 are down to the lowest recorded level in history. It is equally important to add that as at 2011, only parts of four countries (Nigeria, Afghanistan, India and Pakistan) in the world remain endemic for the disease and this is considered as the smallest geographic area in history.

In my next blog post, I intend to discuss global Polio Eradication Initiative (PEI).