Baltimore health officials are trying to prevent a measles outbreak by requiring all Roland Park Elementary/Middle School students to show proof of a measles booster shot when they return to school Monday.
The Health Department issued the mandate last Thursday, after learning of a suspected measles case at the 1,700-student school.
Students can receive free measles vaccinations at the school tomorrow and Thursday between 9:30 a.m. and 1:30 p.m. in the gym, though the school is otherwise closed for spring break this week.
Parents also can arrange to have their children receive the measles booster from their family physician.
The Health Department also will be on hand again at 9 a.m. Monday to offer vaccinations to any students who may have failed to receive the shot before school opens.
However they obtain the shot, students must be able to show proof of two measles vaccinations since their first birthday, or proof of a vaccination within the past 30 days, in order to be readmitted.
The school system will cooperate with that mandate, according to Karen V. Poe, a spokeswoman for the city schools.
"If they tell us that we have to do this, we have to cooperate," said Poe. But she added that turnout at the vaccination clinic this week may be limited by the short notice and the spring holiday that is under way for students.
Although only two confirmed measles cases have occurred in Baltimore this year -- neither of them at Roland Park -- state health officials had recorded a total of 64 cases statewide as of yesterday.
Just over half of those cases occurred in Howard and Anne Arundel counties, where many were traced to students who participated in high school wrestling events in February and March.
Last year, however, Baltimore accounted for 94 of the 213 confirmed measles cases around the state, and local health officials are taking no chances in the city this year.
State law already requires that all students have a measles vaccination before they can enroll in school. But the state now recommends that all children receive a booster shot by age 12, since a single administration of the vaccine has been found to be less than 100 percent effective.
So far, Roland Park is the only city school to be singled out for an emergency vaccination clinic because of concern that an outbreak is about to take place.
But the Health Department this month will offer an optional measles booster shot to every sixth-grader in the school system.
Already, about 2,500 parents have given permission for their children to receive the booster shot, according to a state health department official.
In addition, health officials are reminding adults to be aware that measles cases are on the increase nationwide.
"If you work in the health-care field, you should make sure that you're immune," said Edward Hirshorn, an immunization official for the state health department. "If your school is hit with measles, your kid should be revaccinated."
Measles is a potentially life-threatening disease that starts with three to four days of flu-like symptoms, followed by a bumpy rash that can cover the entire body. It usually runs its course in eight to 10 days.
The disease is most severe -- and dangerous -- for infants and adults, and can result in pneumonia, ear infections that can cause deafness, encephalitis, and sometimes death from dehydration because of severe diarrhea and vomiting.
Measles vaccine is routinely given in combination with a vaccination against mumps and rubella. Virtually all Maryland schoolchildren have been vaccinated once, along with 80 to 90 percent of preschoolers, said Hirshorn.
But a single shot of the vaccine is only about 95 percent effective, he said. That means that 5 percent of those who receive it remain vulnerable after a single vaccination.
And, because the disease is so contagious, it can take hold among that small percentage who remain susceptible, Hirshorn said.
High school students have been particularly hard-hit by the recent resurgence of the disease, but adults born after 1957 are also at risk, said Hirshorn.
Statistics show that about 99 percent of people born before 1957 are immune to the disease, mainly because they contracted it in childhood. But a somewhat smaller percentage of those born after 1957 are immune, said Hirshorn. He cited several reasons.
For one thing, the vaccine was generally given at 12 months of age before 1976, a less effective time to give the shot than the currently recommended age of 15 months.
And Hirshorn also noted that a more fragile measles vaccine was in use prior to 1980.
"We don't recommend that all young adults routinely get a shot," said Hirshorn. But those younger people who are likely to come into contact with the disease -- health-care workers, for example -- should be tested to see if they are immune, he said.
Hirshorn noted that health-care workers accounted for about half of the adults who contracted measles last year.