Binith Sundas Berdewa is just a baby. Small wonder, he is scared of needles. He is crying and screaming as he has just felt a prick from the needle of a syringe.

Binith Sundas doesn't know it yet, but, hopefully, the pain will have been worth it.

He is the first child in Nepal to have received a dose of an injectable polio vaccine - instead of the oral vaccine that is common in developing countries.

The vaccine will protect him against the viral disease which can cause paralysis and lifelong disability among children.

What is more, there is an element of fame to the occasion.

Government and non-government representatives, as well as doctors and nurses have gathered at a hospital in Nepal's capital, Kathmandu, to watch the launch of the injectable polio vaccine in the country.

"It is undoubtedly a very important event that happened today," Santosh Gurup of the World Health organization's office in Nepal tells DW. "We are getting one step closer to eradicate polio from the globe."

Vaccine may cause disease

Health experts will tell you that vaccines are safe - and that is true - but some vaccines are safer than others.

At least, this is the case with polio.

The oral polio vaccine is very popular with children around the world for the simple fact that no needle is involved. The doctor just pops a few drops of liquid into the child's mouth.

Or the child gets a sugar cube with drops of the vaccine on it, as it was done, for example, in Germany.

But the oral vaccine has a huge drawback, says Hendrikus Raaijmakers, chief of the health department of the United Nations Children's Fund (Unicef) in Nepal.

"The oral polio vaccine can in rare cases also cause polio among children," says Raaijmakers. "It doesn't happen often but it does happen."

Raaijmakers says in some countries in Asia and Africa there have even been small outbreaks of polio caused by the vaccine.

The oral polio vaccine contains live viruses that can move from the gut to the nerve system, where they can cause paralysis - just as the wild polio virus does.

Safer, but more expensive

There is another kind of polio vaccine: the injectable one which has just been launched in Nepal.

It contains inactivated viruses.

"It protects against polio but cannot cause polio by itself," says Raaijmakers.

Developed countries, such as Germany and the United States, have been using the injectable vaccine for some time. Germany, for instance, switched from the oral vaccine in 1999, and the US switched the following year.

But developing countries still rely on polio drops - mainly because they are affordable.

The live viruses contained in the oral vaccine replicate inside the human body - meaning, you only need a small amount of the vaccine in order to trigger an immune response, that is immunity.

By contrast, the injectable vaccine requires larger amounts - and that makes it more expensive.

It costs $1 per dose, instead of just a few cents for the oral vaccine - a huge difference for any developing country.

Nepal leading the way

After Nepal, the Philippines, Maldives and Bangladesh are also introducing the injectable polio vaccine.

Gavi, an international organization incorporating the public and private sectors, supports the introduction of the injectable vaccine financially in the world's 73 poorest countries.

Switching from the oral to injectable vaccine is part of the Global Polio Eradication Initiative's strategy to eradicate the disease worldwide by the year 2018.

The initiative is spearheaded by, among others, the WHO and Unicef.

Shyam Raj Upreti, director of the Child Health Division of Nepal's Ministry of Health and Population, says he is very happy that Nepal is leading the way.

"If we don't eradicate polio, what will happen in Nepal and in the globe? So many children will be paralyzed, [disabled] for life. If we complete the eradication, we will save a lot of money - money that we can invest into other public interventions," Upreti says.

A lasting disease

Nepal once had a high number of polio cases. It is now officially polio-free. The last case of polio in Nepal was in 2010.

But doctors say they still see a lot of adult patients who were affected by the disease as children and are now disabled.

"When I was a child, I remember I had three friends of mine who were polio-affected," Sangita Shakya, a pediatrician in Kathmandu says. "Their limbs were very small, they could not walk, they were walking on their forehands! At that time I didn't know what it was but now that I am a doctor, I know that all those cases were cases of polio."

The disease persists in Afghanistan, Pakistan and Nigeria.

From there it can spread to other countries.

"Many past polio cases in Nepal have been imported from its neighboring country India," says WHO's Santosh Gurup. Gurup says it is crucial to continue vaccinating in polio-free countries until the disease has been completely eradicated, worldwide.

The honor of vaccination

Binith Sundas Berdewa can rest now.

"He will be famous after lots of crying," his mother Nisha says and laughs.

She beams with joy and the knowledge that her child is the first to have received the injectable vaccine in Nepal.

The injectable vaccine will complement the oral one in Nepal until 2016.

After that, the oral vaccine will be completely abandoned.

Health experts hope the strategy will free the world of polio by 2018.

That would make polio only the second disease to be eradicated - after smallpox.