A 'cold chain' system has to be set up in order to keep the vaccine cool right up to the moment it is administered to a patient. This has meant the transport of fridges and freezers across the Sudan desert to the towns where the campaign will take place.

An MSF vaccination campaign to protect 70,000 children against measles began in North Darfur on September 25, but plans have been hampered by increasing security concerns in the province. The campaign was set to cover children living in a number of towns in the region, as well as those living in small settlements in the mountainous area known as the Jebel Si.

However, the campaign had to be postponed in some areas until more in-depth information on the security situation allows the team to conduct the vaccination in safe conditions. "The vaccination campaign started in the towns of Seraf Umra and Kebkabyia," explained MSF's head of mission for Darfur, Dr. Natalie Civet.

"We estimate there to be about 40,000 children between the age of 5 and 15 in these two towns and our surveys suggest that vaccination coverage in the past has been extremely poor.

But we have, sadly, been forced to postpone our plans to vaccinate children in the more isolated mountainous region due to security concerns." Insecurity in North Darfur has been increasing since mid-August and the area is now extremely volatile. Estimating security risks poses a daily challenge for the team: robberies and attacks along the roads have escalated and there are growing reports of villages in remote areas being looted.

This has led to more people fleeing their homes and land to seek safety in the already overcrowded larger towns, where humanitarian assistance activities are concentrated.

"In the big towns, many displaced people are already living in cramped conditions," said Dr Civet. "It is extremely important that we do the utmost to protect them against diseases such as measles, which thrives in such circumstances and which can easily be a killer for children already weakened by poor nutrition."

Preparing for the vaccination campaign in North Darfur has been quite a logistical challenge, given the difficult terrain. The measles vaccine has to be permanently kept at a temperature of between 2 and 8 degrees, since it quickly loses its effectiveness if exposed to heat.

Therefore a 'cold chain' system has to be set up in order to keep the vaccine cool right up to the moment it is administered to a patient. "We had to transport fridges and freezers across the desert to the towns where the campaign will take place," explained Dr Civet. "This is no easy task. But with a team of 150 we will hopefully able to work fast and vaccinate around 6,000 children per day in each location."