Since the beginning of the year, Clark County Public Health has reported 50 confirmed measles cases and another 11 suspect cases.


Forty-eight of the cases are in children 18 years and younger and all the cases either were unvaccinated, undervaccinated or an unknown vaccination status.

Health officials say three of the 11 suspect cases were unimmunized when exposed to measles.

To prevent illness, one dose of measles-mumps-rubella, or MMR, vaccine must be given to unimmunized people within 72 hours of exposure. Unfortunately, these three suspect cases received the vaccine more than 72 hours after exposure.

About 5 percent of previously unvaccinated people will develop a rash after being immunized. When administered after 72 hours, the vaccine is less likely to prevent illness, and if the person develops a rash, there is a small chance that the rash is due to the vaccine. People who experience these mild vaccine-associated rashes cannot transmit the vaccine virus to other people.

However, in these situations, it is difficult to determine whether the rash is a benign vaccine reaction or measles illness. For these three suspect cases, specimens are being sent to a specialized laboratory out of state to confirm measles, but it can take more than a week to get the results. Until lab results are available, and in order to protect those who may have been exposed, Public Health is treating these suspect cases as we would treat confirmed cases and releasing information about public locations they visited while potentially contagious with measles.

To date, all lab results of confirmed cases have matched a wild strain of virus, preventable through vaccination, circulating in Eastern Europe. The vaccine strain of measles has never been transmitted person to person.

“The measles vaccine isn’t perfect, but one dose is 93 percent effective at preventing illness,” said Dr. Alan Melnick, Clark County health officer and Public Health director. “The recommended two doses of the measles vaccine provide even greater protection – 97 percent.”