About 22 million people have been vaccinated against measles and rubella in what is the biggest-ever vaccination campaign in the world. The three-week campaign now in progress aims to vaccinate a total of 33 million people aged between five and 25 - about half the country's population.
The campaign is not a response to the threat of an outbreak. Although there has been an increase in the number of measles and rubella cases in Iran over the last three years, with between 10,000 and 15,000 cases of measles this year, there has never been an epidemic. What Iran is seeking to do is to fulfil its commitment to the UN to implement such campaigns, with the global aim of eliminating measles by 2005. Another major objective is to boost routine immunisations against measles and rubella, enabling the focus to be on children under five; more under-fives die of measles than of anything else.
In order to be fully immunised, two doses of the vaccine are needed - one between the ages of 12 to 15 months, the second between the ages of four to six years. Many children born during the last five to six years have already received their first dose, so under this campaign they will receive the essential second dose.
"People up to the age of 25 are being vaccinated now because statistics show that during the 1980s, after they were given the first dose of the vaccine, many people didn't go back for their second dose. This campaign will make them totally immune," Hamid Marashi, a United Nation's Children's Fund (UNICEF) information officer, told IRIN in Tehran.
The operation has taken six years to plan, and it is easy to see why. There are 23,000 vaccination points, 9,000 mobile teams travelling to remote parts of the country, and 120,000 health workers involved. The campaign is running exactly to schedule, with the target figure of 11 million people being immunised a week.
Part of the campaign's success is down to an extensive advertising drive launched before it started. TV, radio and newspapers all carry the message and huge posters line the streets of every major city.
For those in remote areas with no access to media, 30 medical universities - one in each province - received information on the project, which they have been distributing to such remote areas. In a small village near Yazd, there is an immunisation point in the middle of the local market, and just to make sure everybody knows what it is all about, a local volunteer with a loudspeaker is at hand to spread the word.
Surprisingly, the rural areas have been easier to target than the major cities. "Tehran is so big that there are major logistical issues involved. The provinces are extremely well organised and much easier to do than Tehran, which has around 13 million people," Kari Egge, the UNICEF representative in Iran, told IRIN. Mobile teams consisting of three to five health staff - usually nurses, midwives or doctors - have been locating remote villages, nomadic people and population groups on the move, such as refugees.
"What is unique about this programme is that the Afghan refugees are really coming for vaccinations. Lots of Afghan women have been bringing their children. Afghans are taking full advantage of this - and they're allowed to," said Egge.
The benefits for rural areas are not just confined to protection against disease: local volunteers acting as vaccinators have been given a two-day training course on safe injections and mobilisation of people. Health workers have also received training in vaccine management, organisation and monitoring of routine immunisations - indispensable skills for the future which will help to improve implementation of regular immunisations.
This is also the first time disposable needles have been introduced in Iran - a new preventative measure that is hoped will be used for other communicable diseases.
The only real problem the campaign has faced is actually down to its success: so many people have turned up at the immunisation centres that there have not been enough vaccinators, something Egge refers to as a "luxury problem".
The Iranian government has played an integral role in bringing the project together, with the education, interior and defence ministries all collaborating with health workers, UNICEF and the World Health Organisation (WHO). Political support has also been far-reaching, from President Mohammad Khatami, who launched the campaign, to Ali Akbar Hashemi-Rafsanjani, ex-president and chairman of the Expediency Council, down to local village leaders.
"This is impressive on a global scale. I've never seen a campaign that has been so well organised and thorough. I think there's a lot to learn from Iran. The level of staff commitment has been amazing and a lot of people have been proud to take part," Egge said. "I trust by the end of this campaign we should have 98 percent coverage. This is exemplary," she added.