This year's Haj has come to a close without the feared mass outbreak of swine flu, Health Minister Abdullah Al-Rabeah, said Sunday, reporting a total of five deaths and 73 proven cases despite 90 percent of over 2.5 million pilgrims were not vaccinated against the virus. The Haj, the largest annual gathering of people in the world, is considered by health experts as an ideal incubator for the virus. Al-Rabeah said there had been no other serious health problems. The dead were four elderly pilgrims, all over 70, from India, Morocco, Pakistan and Sudan, and a 17-year-old Nigerian woman. All of them had other ailments, including heart disease and cancer, which left them more vulnerable to swine flu, health officials said. “It gives me pleasure to announce ... that the Haj of 2009 was free from any outbreak of disease or epidemic,” the minister said. The Kingdom mounted a concerted campaign to minimize the threat and mobilized 20,000 health workers for the Haj. Despite the relatively minor impact of the virus during the Haj, some experts warn that it is likely spreading silently among pilgrims, and the true extent of the push that gathering has given to the virus won't be known until later, after the faithful have returned to their home countries around the world. Al-Rabeah, however, brushed aside such concerns Sunday, saying pilgrims have been in the country for almost a month, far longer than the weeklong incubation period. “They've had enough time to show symptoms of swine flu, and that hasn't happened,” he said. But he also stressed Saudi authorities will continue to monitor pilgrims until they leave the country, and urged other countries to monitor the pilgrims upon their return home. “Our safety precautions have secured a very successful and safe Haj for pilgrims from around the world with no infectious disease outbreaks,” Al-Rabeah said. Saudi officials, along with American and international health experts, worked to curb any outbreak during the Haj. Health officials circulated among the sprawling tent camp at Mina where the pilgrims lived and gave the faithful cheek swabs for testing later. They also placed hand sanitizer dispensers on walls in the camps, near public bathrooms and at ritual sites, while pilgrims arriving at Saudi airports were scanned using a thermal camera and offered free vaccinations. But authorities also are using the pilgrimage as a test case to build a database, watch for mutations and look for lessons on controlling the flu at other large gatherings like the 2010 soccer World Cup in South Africa. School students across the Kingdom will be vaccinated against swine flu when after the break, he said, in coordination with the Ministry of Education. Nearly 150 pilgrims have undergone heart cath surgeries in Arafat hospitals for the first time in the Haj.