In a report on Monday, the Centers for Disease Control and Prevention (CDC) announced that it has confirmed an additional 41 measles cases in the U.S. The new total brings the number of cases up to 880 in 24 states, the largest number of measles cases in this country since 1994.
The CDC said the rate at which cases of measles are being diagnosed appears to be slowing, but it needs more time to see whether the trend will continue before it can determine that to be true.
All but 11 of the 41 new cases reported were concentrated in New York, the location of two other large measles outbreaks since the fall. Twenty-one new cases were confirmed in New York City, and nine were confirmed in Rockland County.
Health experts have attributed the return of measles, which was believed to have been entirely eliminated from the U.S. in 2000, to the increase in parents who choose not to vaccinate their children.
"We'd previously eliminated this disease not just in the US but in the entire Western Hemisphere, and it appears that now we've profoundly and sadly turned back the clock,” Dr. William Schaffner, medical director of the National Foundation for Infectious Diseases and an adviser to the CDC on vaccines, told CNN.
Officials say that in some cases parents refuse to vaccinate their children based on false information, such as the belief that vaccines cause autism.
Lawmakers in several states, including Maine and Connecticut, are working to limit the reasons parents can opt of vaccinating their children, NBC News reports. Earlier this month, Gov. Jay Inslee (D-Wash.) signed a bill prohibiting parents from citing personal or philosophical exemptions for measles vaccines for children.
The disease is preventable with a vaccine for measles, mumps and rubella (or “MMR). The CDC recommends two doses of the MMR vaccine for children. The first should be given at 12 to 15 months and the second when the child is 4 to 6 years old. Two doses of the MMR vaccine are about 97 percent effective at preventing measles, and one dose provides about 93 percent protection.