Abuja — The dreaded paralysing disease stamped out in the developed orld, is spreading in Nigeria, the Associated Press reported weekend. It quoted health officials as saying in some cases, it's caused by the vaccine used to fight it.

In July, the World Health Organization issued a warning that this vaccine-spread virus might extend beyond Africa. So far, 124 Nigerian children have been paralyzed this year -- about twice those afflicted in 2008.

The polio problem is just the latest challenge to global health authorities trying to convince wary citizens that vaccines can save them from dreaded disease. For years, myths have abounded about vaccines -- that they were the Western world's plan to sterilize Africans or give them AIDS. The sad polio reality fuels misguided fears and underscores the challenges authorities face using a flawed vaccine.

Nigeria and most other poor nations use an oral polio vaccine because it's cheaper, easier, and protects entire communities.

But it is made from a live polio virus -- albeit weakened -- which carries a small risk of causing polio for every million or so doses given.

In even rarer instances, the virus in the vaccine can mutate into a deadlier version that ignites new outbreaks.

The vaccine used in the United States and other Western nations is given in shots, which use a killed virus that cannot cause polio.

So when WHO officials discovered a polio outbreak in Nigeria was sparked by the polio vaccine itself, they assumed it would be easier to stop than a natural "wild" virus.

They were wrong. In 2007, health experts reported that amid Nigeria's ongoing outbreak of wild polio viruses, 69 children had also been paralyzed in a new outbreak caused by the mutation of a vaccine's virus.

Back then, WHO said the vaccine-linked outbreak would be swiftly overcome -- yet two years later, cases continue to mount. They have since identified polio cases linked to the vaccine dating back as far as 2005.

It is a worrying development for officials who hope to end polio epidemics in India and Africa by the end of this year, after missing several earlier deadlines. "It's very disturbing," said Dr. Bruce Aylward, who heads the polio department at the World Health Organization.

This year, the number of polio cases caused by the vaccine has doubled: 124 children have so far been analyzed, compared to 62 in 2008, out of about 42 million children vaccinated. For every case of paralysis, there are hundreds of other children who don't develop symptoms, but pass on the disease.

Experts have long believed epidemics unleashed by a vaccine's mutated virus wouldn't last since the vaccine only contains a weakened virus strain -- but that assumption is coming under pressure.

Some experts now say that once viruses from vaccines start circulating they can become just as dangerous as wild viruses.

But in rare instances, as the virus passes through unimmunized children, it can mutate into a strain dangerous enough to ignite new outbreaks, particularly if immunization rates in the rest of the population are low.

Kew said genetic analysis proves mutated viruses from the vaccine have caused at least seven separate outbreaks in Nigeria.

However, the federal government yesterday denied reports that there is an upsurge in polio cases that emanates from the vaccines that is supposed to fight the virus.

The Executive Director of the National Primary Health Care Development Agency (NPHCDA), Professor Muhammed Pate told Daily Trust that the virus does not comes from administering the vaccines, but can be contacted from the environment by children who have not been immunized.

He pointed out that there has been a dramatic decline in the number of cases recorded in 2009, and that the virus which comes from the vaccine is in the environment and affects children that have not been immunised.

The World Health Organisation (WHO) also said also yesterday that there was no cause for alarm as the said vaccine derived polio can easily be wiped out if all the antigene and vaccines are administered to all children and none is missed during a routine immunisation exercise.

Pate who spoke to our reporter on phone said, 'We have began to see a decline in all the three types of the virus, so we are comfortable with the result we are getting. Unfortunately, the polio virus is out there in the environment, the vaccine virus follows through the natural cause to protect the children administered with the vaccine variety.

After the vaccine has been administered it protects other children who have come into contact with the vaccine strain, in a few cases you get the circulating vaccine derive polio, but that is easily dealt with if you have a good immunization team and system that gives you all the monovelent antigens, the three types.

The trend is downwards, and we are comfortable with the process so far made and we are not unduly alarmed , and the numbers are not true, in total we have far lesser virus this year than we had last year, in terms of paralysed children we have had 40% reduction, than last year, in all the three types of cases type 1, 2 and 3.

WHO Regional Director Dr Peter Eriki, however, told Daily Trust that the said report occurred in May in places where children were not fully immunized.

He assured the public that If the vaccine is administered, it will simply wipe out the virus.

"A lot has happened between now and may, and we have had a few rounds of vaccines and the cases are coming down. There is no need to worry, all we need to do is to focus on the efforts we have been making to ensure that all the children are vaccinated, the country is on the right track, the system of involving all the traditional leaders in advocacy is really working."

According to him, the vaccine derived polio is weaker, but the one the country should be concerned about is the type one which is the most dangerous which paralysis immediately.

"The vaccine driven one affects children through faeces and those children who play in the same environment, who are not vaccinated, it does not affect those children who are vaccinated.

"But what is important to note is that this same vaccines is the one used to eradicate polio in other parts of the world, so we are on the right part, efforts should be intensified to ensure that all children are immunized to avoid the vaccine derived polio."