U.S. Measles Cases Continue to Plunge
Fewer than 100 cases in 2000; vaccine coverage cited
THURSDAY, Feb. 14, 2002 (HealthDayNews) -- Measles cases in the United States plunged to a record low in 2000, because of widespread vaccine coverage against the potentially deadly virus.
Of the 86 cases reported for that year, 62 percent were either imported from other countries, like Japan, Korea and Ethiopia, or linked to imported cases, according to a new report from the Centers for Disease Control and Prevention (CDC). Of the 26 imported cases, 14 involved Americans who traveled abroad and came home with the virus. There were no reported deaths from the disease, which kills an estimated 800,000 people, mostly young children, worldwide.
For the last few years, states have reported a combined total of approximately 100 cases of measles. So the most recent figure, 14 percent below that in 1999, is a "fairly significant" drop, says Dr. Brent Lee, a CDC infection expert and a co-author of the report.
However, Lee says preliminary data show that the number of cases crept up again in 2001, and will probably wind up between 90 and 100. That would still be far below the most recent peak in the incidence of the viral illness, which sickened more than 55,000 people in this country between 1989 and 1991.
The cause of that surge was lax vaccination habits by Americans, who became susceptible to the imported virus. Vaccine coverage for measles, which comes as part of a triple inoculation that also fights mumps and rubella, is now extremely high, reaching well over 90 percent children over age 6. Immunization guidelines call for one dose of measles vaccine to be administered between 12 and 15 months, when it's 95 percent to 98 percent effective. To cover that gap, health officials recommend a second shot between ages 4 and 6.
Every state but Idaho requires children to have two shots of measles vaccine by the time they reach school age, Lee says.
The CDC report found that 23 of the 86 patients had a history of measles vaccination, while 40 never received the shot. Of those, nine were under a year old. Vaccination status couldn't be determined in another 23 patients.
In general, measles cropped up sporadically in 2000, and each imported case led to less than one other infection. But the year did see a few small outbreaks, including two in New York's Oswego/Onondaga and Kings counties, in which nine and eight people, respectively, fell ill.
Three states -- New York, California and Nevada -- accounted for almost 60 percent of the measles cases in 2000, while 20 states in all reported the disease. Only 41 of the nation's 3,140 counties (1 percent) had a confirmed case of the infection that year. New York led the nation with eight imported measles cases, followed by California with six and Hawaii and Vermont, which each had three.
Judy Lester, a public health nurse at the Oswego Health Department, says her county was unable to determine if the source of the measles outbreak there was imported or domestic. However, Lester says epidemiologists believe a high school athlete may have picked up the virus while traveling to another state and spread it around his school.
In either case, Oswego isn't expecting a repeat of the 2000 outbreak, says Lester, who adds that changes in New York's vaccination requirements should prevent such a problem. "The kids in that outbreak had the one dose [of vaccine], and two doses wasn't a requirement" when they were entering school. "That's been somewhat remedied and the kids coming up behind them had the second dose," she says.
The report also highlights the case in 2000 of a 24-year-old athlete on the U.S. Olympic team who appears to have unwittingly acquired the virus in Japan and brought it back to Utah, where she was competing in an event. She then left the country again for Italy, where she developed the trademark measles rash. Three other people in Utah contracted the infection, which officials were able to trace because of an alert U.S. team doctor, who notified CDC
"If we had not known through the report of the team physician, we wouldn't have known the source" of those cases, Lee says. "In some of the other situations without a documented source, it may have been something similar."
Some athletes are more prone to certain infections. Wrestlers, for example, often contract a virus called herpes gladiatorum, which causes sores on the head, neck, and shoulders. But is the Olympic Village a convention center for dangerous organisms?
Not usually, says Dr. Steven Ostroff, associate director of the CDC's National Center for Infectious Diseases.
"There's not a significant history of major disease problems associated with the Olympics. But this is the peak of flu season, and there are participants from parts of the world that wouldn't necessarily have received the same types of childhood vaccines standard elsewhere," Ostroff says. "It's a great opportunity for not only people to get together but for microbes to get together and get passed from person to person."
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