DAKAR, 6 May 2011 (IRIN) - Insecurity has forced health officials in Côte d'Ivoire to delay a polio vaccine campaign in Bas Sassandra, a southern region where at least three people have recently contracted the highly infectious disease.

"Polio has been gaining ground again in Côte d'Ivoire because many children have not been able to receive the vaccine in recent months due to the crisis," said Hervé Ludovic de Lys, designated representative of the UN Children's Fund (UNICEF). "It is therefore important to catch up with vaccinating as many as possible to prevent children contracting polio and becoming paralysed for life."

A vaccine drive that was to take place in Bas Sassandra 6-9 May has been tentatively set for the following week, after reports that there were armed groups near the area, according to N'zué Koffi, head of immunization programmes at World Health Organization (WHO) in Côte d'Ivoire.

This is the second time in two months that conflict has disrupted operations to protect Ivoirians from polio – the country was not included in a West Africa vaccination drive in March due to post-election violence.

Despite a decline in hostilities since April, insecurity in certain areas is still preventing health workers and aid groups from meeting some people's needs, de Lys told IRIN. In the upcoming drive the Health Ministry, with WHO, UNICEF and Rotary International, plan to vaccinate hundreds of thousands of children in Bas Sassandra – some 250km west of the main city Abidjan – with a nationwide campaign planned for later in the year.

UN workers said that after recent clashes in Abidjan between the national army and pro-Laurent Gbagbo fighters, some armed groups, including Liberian mercenaries, were reported to be moving west.

No cure

The three cases reported in Bas Sassandra are wild poliovirus type 3 (WPV3), last detected in Côte d'Ivoire more than 10 years ago, and in West Africa (northern Nigeria) in 2008. WHO said a case of WPV3 was also detected recently in Mopti, Mali.

All three serotypes of wild poliovirus infect children and can lead to paralysis, WPV1 being the most virulent. WPV3 is more difficult to detect and so can circulate "silently" for a longer period than WPV1, said Oliver Rosenbauer, spokesman for the WHO polio eradication group in Geneva.

The virus is transmitted through contaminated food and water and multiplies in the intestines. Many infected people have no symptoms but excrete the virus in their faeces, transmitting infection, according to WHO. There is no cure, so prevention by vaccine is the only way to avoid the disease, which can paralyse within hours.

"The overriding and immediate priority is to stop these two WPV3 outbreaks completely, as rapidly as possible," Rosenbauer told IRIN. "But it has to be done in such a way as to also maintain population immunity to WPV1." A WPV1 outbreak affected several West African countries in 2009-2010 and had only recently been stopped, he said.

Health officials are evaluating surveillance systems to ascertain whether the gaps are primarily in Côte d'Ivoire or in other parts of West Africa. Immunization drives in the region will continue, but a lack of funds could set back progress.

Rosenbauer said there is a global shortfall of US$665 million until the end of 2012.

"It's critical that these funds be rapidly mobilized to fully implement outbreak response and strengthen surveillance in West Africa," he said. "Nigeria has seen a 95 percent reduction in cases over the past year. Eradicating polio there would have a huge impact on all of western Africa, as historically the virus has spread from Nigeria into Niger and Burkina Faso, and then down into Côte d'Ivoire."

Source: The Integrated Regional Information Networks (http://www.irinnews.org )