By VOAHello, and welcome to As It Is from VOA Learning English.I'm Christopher Cruise in Washington.Today on the program, we report on plans by public health workers to vaccinate 23 million children against polio in Middle East countries."...polio does not know borders, does not know checkpoints, does not need a visa."The workers are even vaccinating children trapped in the fighting in Syria.But first we report on how polio has become the latest source of tension between Pakistan and India. Officials in Pakistan are criticizing India's new rules limiting travel between the two countries. India believes the rules will help keep polio out of the country.Fighting polio -- the subject of our program today, as you learn everyday American English with VOA.Pakistan Criticizes India's Border Action on PolioOfficials in Pakistan are not happy about India's recent announcement that it would restrict travel between the two countries. Indian officials say they are trying to keep the polio virus from entering the country.Pakistan is one of only three countries in the world where polio continues to spread. The other two are Nigeria and Afghanistan.Pakistan's fight against polio has suffered in recent years. Islamist militants linked to the al-Qaida terrorist group have fought vaccination efforts in the northwestern tribal areas. They say American intelligence agents are using vaccination activities to gather information.A Pakistani health worker administers polio vaccine to children in a slum of Rawalpindi, Pakistan.Some medical workers and their guards have been killed as they travelled the country to vaccinate people.The World Health Organization confirmed in November that more than 12 children were hit by the polio virus in Syria. The WHO says the polio virus that struck them is linked to the virus from Pakistan.Indian diplomats in Islamabad, Pakistan announced new travel rules for Pakistanis. They said travelers from Pakistan -- both adults and children -- must have had a polio vaccine at least six weeks before they are permitted to enter India.The announcement said the new rule would take effect at the end of January. Officials said the decision was made to keep India free of polio. They said India had worked hard to keep the disease from spreading.But Pakistani officials do not believe the decision was necessary.Sartaj Aziz is Pakistan's advisor on national security and foreign affairs. He spoke to reporters in Islamabad after the decision was announced. Mr. Aziz said Pakistan is strengthening its fight against polio. He said Indian officials should not use the issue as a reason to refuse to let Pakistanis enter India.But India says the new rules target not just Pakistanis but people from all countries where polio is still active.The ban may make crossing the border difficult for the hundreds of thousands of Pakistanis who have families in India.You are listening to As It Is, a program designed to help you learn to speak, read and write American English.Millions of Children in the Middle East to Get Polio VaccinePublic health workers are now trying to give the polio vaccine to 23 million children in Middle Eastern countries. It is the second part of the largest vaccination campaign ever in the area. It follows an outbreak of polio cases in Syria. The disease has killed 17 people there.This map shows new cases of polio in Syria.Medical workers must vaccinate every child under the age of five in the seven countries in the area.The civil war in Syria is interfering with efforts to reach the people that need vaccinations.UNICEF spokeswoman Juliette Touma says the first vaccinations in November reached more than 2 million Syrian children."Around 600,000 were in contested areas where it was hard to reach. But it's obviously not enough -- there are children who are trapped in sealed-off areas that we could not reach that we really need to reach, and we do hope to reach in the second round."Ms. Touma says the polio cases in Syria only add to the suffering of people there."Syria has been polio-free since 1999. And then suddenly, we have, on top of everything, as if we needed something else to increase the suffering of children, we have polio."Some opposition groups have said they have not been able to get the polio vaccine because UN agencies that run the campaign must work with governments.A health worker administers polio vaccine to a child as part of a UNICEF-supported vaccination campaign in Damascus, Syria.Ms. Touma says the campaign is negotiating with all groups to deliver the vaccine to as many children as possible."What we need to have is a commitment for us to access children wherever they are, regardless of their family's political affiliation, because polio does not know borders, does not know checkpoints, does not need a visa."Polio spreads easily through contaminated food and water. Most of the victims are children. Workers must give people more than one vaccine before they are fully-protected from polio. Four more week-long vaccination campaigns are planned after this one.There have been polio cases in Somalia, and from there polio spread to Kenya and Ethiopia, which had been free of polio.And that's our program for today. It was written from reports by VOA Science Correspondent Steve Baragona and other VOA reporters in Washington.Every day on As It Is, we report on issues that we believe are of interest to you.You can tell us what you want to hear on a future show.We read every message you send us.You can also go to our website -- 51voa.com -- and click "Contact Us." While you are there you can read, listen to and download our programs. You can also find podcasts, captioned videos and lessons to test your English skills.Follow us on Facebook, LinkedIn, iTunes, Twitter and on our YouTube Channel, all at VOA Learning English.And don't forget to listen to VOA World News at the beginning of very hour Universal Time every day of the year.Thank you for spending some of your time with us today.I'm Christopher Cruise reporting from VOA Learning English headquarters in Washington.