The U.S. Centers for Disease Control and Prevention has determined that a case of measles, first diagnosed by doctors at the Martha’s Vineyard Hospital and later confirmed by state public health epidemiologists, was not measles.

The development has triggered a range of reaction from relief to exasperation. The response to what was first thought to be a measles diagnosis has also raised questions about how state and local public health officials work with the hospital and Island doctors to handle an outbreak of infectious disease in a small, geographically remote community.

Those issues will be the focus of an effort to improve future response to an outbreak, hospital president and chief executive officer Timothy Walsh said this week..

In an interview with the Gazette, Mr. Walsh said state Department of Public Health protocols did not necessarily adapt well to the Vineyard, especially when it came to communicating with a

concerned public. As a result the communication fell mostly to the hospital, which is a departure from the normal protocol.

“There was a little confusion,” Mr. Walsh said. “Because they’re used to dealing with much bigger places, they don’t really understand it,” he said, referring to the DPH. “If this turned out to be an epidemic, all the people doing the communication would have been in the emergency room taking care of patients.”

The unvaccinated child originally thought to have the highly contagious disease apparently had a similar virus that tested positive in the same way measles would, according to Dr. Jeffrey Zack, chief of emergency medicine at the hospital. He said the virus, which like most viruses does not have a name, was generally contagious but not dangerous. The symptoms were much less severe than measles.

“It’s not known to have done anything other than cause high fever, rashes and respiratory symptoms,” Dr. Zack said. “We screened about 10 cases where we felt it was close enough to test for, but they all ended up negative [for measles].”

Dr. Zack said misidentification of the disease in lab tests is beyond rare. “You have a clinical picture that was mimicking measles, you had an initial test from the (Massachusetts) DPH that said it was measles,” Dr. Zack said. “It walked like a duck and it talked like a duck but it was a platypus. It’s a bit of a freak occurrence. Now we understand why we didn’t see any more cases.”

A spokesman for the state DPH, which confirmed the measles diagnosis and handles protocols for preventing the spread of disease, issued a statement by email this week.“Partially thanks to its vaccine-driven rarity, diagnosing measles is complex from both clinical and laboratory perspectives,” said Scott Zoback. “While final testing has not confirmed measles in the patient on Martha’s Vineyard, it is important that public health authorities at all levels respond immediately to suspected measles to carry initial diagnostic testing, consult with the CDC, and institute control measures that can prevent a serious outbreak.”

DPH declined to make anyone available for an interview.

Meanwhile, the CDC uses a test that detects antibodies in blood that fight measles to verify a case. The tests are not foolproof and will occasionally produce false positive results. When additional confirmation is necessary, more specialized tests are available.

The child originally thought to be infected with measles lives in another state and visits the Island in the summer. The child came to the Martha’s Vineyard Hospital emergency room on June 17. The appearance caused personnel to treat the hospital as an infectious site. They began to verify the vaccination status everyone who came near the patient, including nurses, doctors, and other patients in the emergency room. Those without verification of vaccination were isolated and tested.

Late Friday afternoon, about 48 hours after the initial exam, DPH notified the hospital that cultures taken from the patient confirmed the original diagnosis of measles. That triggered a protocol involving DPH, local boards of health and the hospital. Epidemiologists traced the movement of the child and the child’s family beginning on June 8, and issued an alert informing the public that child was at West Tisbury, Chilmark and Aquinnah libraries at various times while infectious. The child also visited the Airport Laundromat, Ryan Family Amusements and Sharky’s Cantina in Oak Bluffs.

Dr. Zack said that as a result of the publicity, about 125 people were vaccinated against measles and other infectious childhood diseases at two free clinics organized by the hospital staff on June 24 and 25.

“It’s a good and a bad thing,” Dr. Zack said. “Obviously it caused a great amount of anxiety and concern on the Island. It was a good learning experience for us in terms of responding to a potentially dangerous public health infection. We got a lot of practice in terms of what worked, and what didn’t work.”

Some people first learned of the measles case not from DPH or the hospital, but through social media outlets. On Monday, June 22, the hospital issued an alert and school administrators sent a letter to the parents of all students. J.B. Blau, who owns Sharky’s Cantina in Oak Bluffs, one of the sites named as a potential site for exposure, kept his extensive customer list informed with frequent social media posts.

In a close knit, well connected community, effective communication is critical, Mr. Walsh said. He plans a debriefing with hospital personnel, and then a debriefing with DPH, to identify areas where improvement is possible. One key focus will be on communication.

“What I would like to do is set up what our communication is going to be, expectations for everybody,” Mr. Walsh said. “We need to use our website and the newspapers. Even at that, when you’re in the midst of [a response], DPH drives that train. They have a lot of stuff they have to do. If we have a lot of sick patients, you can’t count on us to do a lot of communication. On the Island, everybody expects the hospital to do that, and that doesn’t happen anywhere else.”

Dr. Zack said he thought the hospital did a good job of getting information out, but it was a role that made extra work for the medical staff whose main focus gearing up for clinics and getting ready for the real possibility of treating dozens of measles cases. He said in a real scenario where infectious disease was spreading, it would be difficult to take on the communication role.

“Certainly communication was complicated,” Dr. Zack said. “We’re really not responsible for that, but the alert system didn’t translate well to the Island, and we were forced to take a role. It sort of made us stay for six hours extra a day to handle logistics and planning. We still got it done, but worrying about the communications piece, who was saying what, was a little extra piece.”