Six measles cases reported in Tennessee outbreak

Tennessee Department of Health officials have reported six cases of measles — five among unvaccinated infants and one in an unvaccinated adult — with that number expected to rise.

Timothy F. Jones, MD, state epidemiologist for the Tennessee Department of Health, told Infectious Diseases in Children that after two cases of measles were confirmed last week, an investigation of close contacts revealed four additional cases. All of the infants were too young to receive the measles-mumps-rubella vaccine; the adult refused vaccination, he said. All six cases are in Shelby County.

Timothy F. Jones

According to Jones, an investigation is ongoing to identify any unknown cases of measles. The investigation involves identifying close contacts and verifying their vaccination status to ensure they are not susceptible to the virus.

“With all cases of measles, our No. 1 priority is identifying all of their potential contacts,” said Jones, an Infectious Disease News Editorial Board member. “Measles is probably the most communicable disease that we ever deal with. It remains airborne, so you can be in a room that a patient was in an hour ago, then the patient is gone, and you can still get it just from lingering in the air. So, the numbers can get pretty big. We had a number of patients that were in doctors’ offices, hospitals and some other group activities where potentially hundreds of people were exposed.”

Jones said this outbreak is particularly difficult to contain because the initial patient has not been identified.

“Measles is always imported from somewhere, because we don’t have measles circulating in this country,” Jones said. “In this particular case, we will not be able to identify who brought it in, sort of like what happened in Disneyland [starting in December 2014 in Southern California].”

The investigators have identified three seemingly unrelated clusters among the six cases, which suggests the virus has been intermingled throughout the community.

“Nothing whatsoever linked some of the cases, which means that whoever patient X was spread it to more than one group,” Jones said. “That means the cat is already out of the bag, and in a situation like that our expectation is that it’s going to be more difficult to control because we don’t just have one event or social group to descend upon.”

Due to these circumstances, Tennessee health officials expect more cases of measles involved with the current outbreak.

“It’s smoldering out there throughout the community, so I expect that we will see many more cases before this is over,” Jones said.

Jones also said, however, he is optimistic that they will be able to contain the current flare-up because of the high vaccination rates in Tennessee.

“I do not think that this will blow up anywhere close to what happened in California,” he said. “We have good immunization rates here in Tennessee, and this is a very, very effective vaccine. All of the cases so far have been unvaccinated, so we have not seen any vaccine failures.” – by David Costill