Mexico said on Monday it was rushing measles vaccinations to 16.5 million people across the country after an outbreak of the disease among adults sparked fears of an epidemic.

While the health ministry opened a telephone hotline for the public, Health Minister Julio Frenk played down the risk of a repeat of Mexico’s 1989-1991 measles epidemic that killed several thousand people.

“The risk of an epidemic on a large scale? No. That’s exactly why we are taking these measures. With this operation, there is no possibility of this becoming a large-scale problem,” he told a news conference.

The ministry said 64 cases of the disease had been documented so far this year, two thirds of those involving adults, marking a jump from the 44 cases recorded in the whole of 2003. No deaths have been reported to date.

Frenk said the extra vaccine was being taken to clinics, schools, universities and workplaces and administered to the 13-39 age group which is most at risk from measles - a disease that kills around 600,000 people worldwide each year.

Local media spread alarm by reporting a shortage of vaccines and described long lines outside doctors’ surgeries as adults - who suffer more serious effects from measles than children - raced to get immunized.

The head of the health committee in the lower house of Congress, Jose Angel Cordoba, called the situation “an emergency” and urged the government to free up income from oil sales to fund a vaccination program.

The most deadly of vaccine-preventable diseases, measles can lead to complications like ear infections, pneumonia and encephalitis, or inflammation of the brain, which can cause deafness and brain damage. For pregnant women, exposure to measles can cause miscarriage or premature birth.