Officials in Nigeria’s northern Kano state say parents who refuse to have their children vaccinated against polio may be prosecuted and could face jail time. The government order issued this week comes as the United Nations children’s agency, UNICEF, has been pressuring Nigeria’s northern states to promote vaccination against the highly contagious disease. Officials began a four-day immunization campaign in Kano on Thursday, with the goal of immunizing six million children.

The World Health Organization says a polio outbreak began spreading in the second half of 2008. Efforts to contain it have been complicated by rumors that the vaccine is harmful to children.

The polio vaccine is given in a series of shots. Children should receive a total of 4 shots. The first shot is usually given when the child is 2 months old. The booster shots are then given at 4 months, 6 to 18 months, and then 4 to 6 years of age. Polio vaccine is for use in adults and children who are at least 2 months old.

Polio affects the central nervous system and spinal cord. It can cause muscle weakness and paralysis. Polio is a life-threatening condition because it can paralyze the muscles that help you breathe.

This vaccine works by exposing a person to a small dose of the bacteria or a protein from the bacteria, which causes the body to develop immunity to the disease. This vaccine will not treat an active infection that has already developed in the body.

If polio vaccination were stopped in the United States, there would be millions of susceptible children within a year. Since wild polio infection still occurs in many parts of the world, the virus could be imported and an epidemic could result.

Polio cases have decreased by over 99% since 1988, from an estimated 350 000 cases then, to 1604 reported cases in 2009. The reduction is the result of the global effort to eradicate the disease.

In 2010, only four countries in the world remain polio-endemic, down from more than 125 in 1988. The remaining countries are Afghanistan, India, Nigeria and Pakistan.

As long as a single child remains infected, children in all countries are at risk of contracting polio. In 2009-2010, 23 previously polio-free countries were re-infected due to imports of the virus.

In most countries, the global effort has expanded capacities to tackle other infectious diseases by building effective surveillance and immunization systems. Knowledge of the poliovirus has expanded with aggressive research carried out under the eradication effort.

The last case of wild poliovirus infection acquired in the United States was in 1979. Except for an occasional importation, all cases of paralytic poliomyelitis since 1979 have been caused by live oral polio vaccine.

The last case of wild poliovirus infection in the Western Hemisphere occurred in Peru in 1991. However, thousands of poliovirus infections still occur in other parts of the world. The majority of cases are now reported from the Indian subcontinent, Asia, and Africa.

Success and full eradication hinges on closing a substantial funding gap to finance the next steps of the global eradication initiative.

Written by Sy Kraft