Before last year, pediatrician Stuart Simko had only seen historical case studies of measles - with its signature blotchy red rash - once infecting millions of children each year, before a vaccine was invented.
But in the past two months, he has seen six cases - in person, for the first time.
The children were "very sick", the South Carolina doctor said, with a high fever that was diffcult to bring down.
"It's a terrible, terrible disease that can cause mortality, and we don't say that to scare people, but people need to know the risks," said Simko, who works for Prisma Health. "It is hard to see a sick child knowing that it could be prevented."
Simko's six patients are among 789 people infected in South Carolina over the past few months, the vast majority unvaccinated children. It marks the largest measles outbreak since the US declared the disease eliminated in 2000. The US, with outbreaks in several states, is now on the verge of losing that status - following in the United Kingdom and Canada's footsteps. Two school-aged children died in a Texas outbreak last year.
