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Officials at the South Carolina Department of Public Health declared their record-breaking measles outbreak to be over on Monday after no new cases emerged during the past 42 days.
“Though we reached nearly 1,000 cases, we are grateful that, by and large, it remained confined to one county and did not spread statewide, as was always our concern and fear,” Dr. Brannon Traxler, the department’s deputy director and chief medical officer, said at a news conference.
Here are seven things to know about the largest U.S. measles outbreak in more than 35 years:
Most people who got infected weren’t vaccinated
Of the 997 measles cases documented in the outbreak, 932 patients were unvaccinated, 19 had an unknown vaccination status, and 20 were only partially vaccinated with only one dose of the two-dose MMR (measles-mumps-rubella) vaccine, according to the department’s data.
Just 26 people were fully vaccinated with two doses of MMR vaccine. Two doses of the vaccine is about 97% effective in providing protection against measles infections; one dose is about 93% effective, according to the Centers for Disease Control and Prevention.
Infections, increased vaccination credited in stopping outbreak
Traxler said there are three main reasons state health officials think the outbreak has ended: the large number of people infected, widespread community cooperation with quarantine and isolation, and increased vaccination against measles in recent months.
The 997 people sickened with measles developed immunity to the disease, Traxler said. “Though that carried with it, of course, the risk of severe illness, a weakened immune system and the potential for devastating complications even years from now,” she said.
Another important factor in stopping the spread of the virus, she said, was that the “vast majority” of people who were infected or exposed followed public health instructions to stay home and avoid infecting others.
Lastly, thousands of people got vaccinated. In Spartanburg County, she said, an additional 3,788 doses of MMR vaccine were administered during the six months of the outbreak compared with the previous year.
“In particular, January and February were record months for MMR vaccination in the state,” she said.
Risks for future measles outbreaks continue in South Carolina
This outbreak may be over, but outbreak risks remain in Spartanburg County and across the state. Traxler noted that pockets of people who are not protected against measles remain in many communities.
“We’re going to continue to see sporadic cases that are going to be travel-associated most likely,” Traxler said, noting the goal is to keep one of these travel cases from sparking a larger outbreak.
“If we don’t continue to see increases in vaccination, I’m worried that we could see another large – maybe not this large, but hopefully not – but another large outbreak in a community where it gets introduced from someone who had traveled.”
State’s $2.1 million cost is only part of the outbreak’s bill
The department estimates that the outbreak response cost the state of South Carolina $2.1 million. But that was just the costs the department could calculate for staff time, vaccination costs, and other direct expenses.
It doesn’t include all of the costs to the health care system, schools, businesses, and beyond, she said. “What were the economic impacts to the state of parents who had to miss work?” she asked. It’s not part of that number.
Outbreak began with 5 cases, centered in Spartanburg County
The outbreak was first identified in early October, with just five cases. For weeks the virus seemed to spread slowly – then the holiday season began.
On the Tuesday before Thanksgiving, the state had logged 55 measles cases. By Dec. 12, there were 126 cases – and more than 300 people in quarantine, Healthbeat’s timeline of the outbreak shows.
By mid January – after the December holidays and multiple public exposures at schools and churches – the outbreak surged, with more than 100 new measles cases being identified every few days. By Jan. 20, the department had documented 646 cases. Cases slowed during February and March.
The last time the state announced a new case in the outbreak was on March 17, the day the case total reached 997.
Before the measles outbreak could be declared over, there needed to be two incubation cycles – or 42 days – without any new cases.
Winter break school closures delayed investigations, quarantines
During the critical December holiday period – before the outbreak surged – South Carolina health officials were hampered in their efforts to control measles exposures because of winter break school closures, Healthbeat reported earlier this year.
Internal department records, obtained by Healthbeat, revealed how outbreak investigators were delayed in their efforts to quickly quarantine schoolchildren exposed to measles right before the two-week winter break period began. Because schools were closed, outbreak investigators couldn’t reach anyone at multiple Spartanburg schools to get contact information for classmates, staff, and others who had been exposed to infected people.
To prevent similar communications gaps during the recent spring break period, the department contacted schools across the state’s 11-county Upstate region to identify a person who would be available to provide attendance and contact information during the spring break closures of schools and administrative offices.
Department’s response, lessons learned to be evaluated
“The outbreak is over, but our work to understand and prevent measles and future outbreaks is not,” Traxler said. “A thorough after-action review and analysis is being started. We believe our outbreak response team did a tremendous job under really unprecedented conditions. But there are always things that we can learn from and improve on in our future with future responses, and we are committed to doing so.”
One of the things the department did well, she said, was urging members of the health care community to be pro-active in immediately reporting any suspected measles case – even before any test results come back. That early heads-up, she said, allowed the department to immediately start educating the patient about the need to isolate and begin earlier contact tracing.
Alison Young is Healthbeat’s senior national reporter. You can reach her at ayoung@healthbeat.org or through the messaging app Signal at alisonyoungreports.48.
