The measles outbreak in South Carolina — the largest the United States has had in decades — has ended, state health officials announced Monday.
There were nearly 1,000 confirmed cases over about six months, including at least 21 hospitalizations. No new cases associated with the outbreak have been reported in more than 42 days, the state health department said, marking two incubation periods – the time it would take to get sick after being exposed to the virus – without any transmission.
The South Carolina outbreak started in October, contributing to a record-breaking year for measles cases in the US along with the large, deadly outbreak in West Texas. The nation is on track to record even more cases this year, which would again make it the worst year since measles was declared eliminated in the US in 2000 — a status that is now under threat.
Public health experts have largely attributed the rise in measles cases in the US to falling vaccination rates; more than 90% of the cases in South Carolina — and nationwide — have been among people who had not received the measles-mumps-rubella (MMR) vaccine. The vast majority are children.
But there is a very early signal that MMR vaccination rates may have ticked up among young children in the US.
Some experts say that hearing about multiple large outbreaks and record numbers of measles cases nationwide — and confronting exposures near home — could have encouraged some hesitant parents to vaccinate their kids, and there’s “cautious optimism” about a potential shift in vaccination trends.
Safe, effective vaccines
South Carolina public health leaders say that increasing vaccination coverage played a significant role in helping to get the outbreak under control.
“Vaccination – combined with other opportunities for good, solid public health work – really can be effective, even against some of the most contagious viruses,” Dr. Brannon Traxler, deputy director and chief medical officer with the South Carolina Department of Public Health, said at a news briefing Wednesday.
The MMR vaccine is highly effective. One dose prevents disease about 93% of the time, and two doses raise that protection to 97%. Sean Rayford/Getty Images
Along with vaccination, aggressive contact tracing, case investigation and quarantine protocols helped “put a fire break ring around” the outbreak as it burned through the susceptible population, Traxler said. But the response cost the state about $2 million.