Health officials in Great Britain are scrambling to vaccinate one million children against the measles. They are holding emergency vaccination clinics after more than 1,200 people became infected with the disease this year.
"What we're seeing is predominantly children in secondary school, children between 10 and 16 years old," said Dr. David Elliman with the Royal College of Pediatrics.
More than a decade ago, millions of parents stopped immunizing their children against the highly infectious disease after a medical paper suggested a link between the combined childhood vaccine for measles, mumps and rubella and autism. The paper has since been discredited, but at the height of the scare, immunization rates plummeted.
"This is the group that we are now seeing that has measles," Dr. Elliman said.
More than 100 people infected with measles this year had to be hospitalized. Some suffered serious complications including pneumonia and meningitis.
Measles is still one of the leading causes of death in children under 5 around the world, but in industrialized countries, most just get a rash and a fever.
The vast majority of British toddlers are once again being vaccinated.
In the United States there have been 22 cases of the measles this year, including three that were traced back to Britain.