Students at Oakland Mills High School in Columbia were being barred from classes today if they couldn't prove they had received a second round of vaccinations against measles.
Anne Arundel County plans to take the same action next Wednesday at Arundel High School in Gambrills, as public health officials in Central Maryland scramble to stay ahead of a growing outbreak of the viral illness.
"This is not a disease to fool around with," said Dr. Elin Gursky, director of epidemiology and disease control for the Prince George's County Health Department.
So far this year, nine confirmed measles cases and 17 suspected cases have been reported from Howard, Prince George's, Montgomery and Anne Arundel counties, said Dr. Diane Dwyer, chief of the state Department of Health and Mental Hygiene's Center for Clinical Epidemiology.
"We actually have fewer cases than last year [at this time]," Dwyer said. But last year's outbreak "took off" in March and totaled 213 cases by year's end, the biggest outbreak in a decade.
"That's why we felt it necessary at this time to re-emphasize that measles is in the community," she said.
Health officials now recommend that parents have their children immunized against measles, mumps and rubella (German measles) at 15 months of age. Immunization is required for enrollment in public schools.
A second immunization at the time the child enters middle
school is now recommended by the U.S. Centers for Disease Control and by the American Academy of Pediatricians.
Measles, or rubeola, can be very serious, even fatal, Dwyer said.
It is a viral infection, spread by coughs and sneezes. It is characterized by high fever, coughs and sneezes, followed by a reddish skin rash.
Last year, 29 percent of Maryland's measles victims had to be hospitalized for such complications as dehydration, pneumonia and encephalitis, or brain inflammation. Encephalitis can result in permanent brain damage.
No deaths are believed to have occurred from measles in Maryland last year. But 60 people died nationwide, up from 41 the year before.
The number of measles cases in the United States has been growing in the past three years, up from 18,000 in 1989 to more than 25,000 cases last year. The reasons for the increase aren't clear.
Dr. William Roper, director of the national Centers for Disease Control in Atlanta, says one of the main reasons is a low immunization rate among preschoolers.
But as many as half the measles cases today are occurring among children who were immunized in early childhood. For some reason, those vaccinations failed.
The CDC has launched a $500,000-a-year research effort to determine whether the measles virus has evolved into a more virulent organism in recent years. If it has changed, it may no longer be as vulnerable to the measles vaccine, which is still made from the measles virus that was circulating in 1954.
The timing of a child's initial vaccination may also be a factor.
Dwyer said more than half the children now in high school received their first vaccinations before they were 15 months of age. "Those have had a slightly higher vaccine failure rate," she said.
And that's why school children are now advised to have a second vaccination before they enter middle school. Older children are advised to get a second vaccination before high school or college.
Howard County health authorities took action at Oakland Mills High School this week after seven students came down with symptoms resembling measles. Two of those cases have since been confirmed as measles, said Ruth Talbot, director of nursing for the county health department.
In all, Howard County has counted 12 suspected measles cases, and four confirmed cases.
For those students at Oakland Mills High School who could not provide proof that they had received two doses of measles vaccine since their first birthday, or other proof of immunity, the health department provided free immunizations on Tuesday and yesterday. The number of students immunized was not immediately available.
Talbot said as many as 600 students at Patuxent Valley Middle and Clemens Crossing Elementary schools were immunized recently after suspected measles cases were reported there.
Three students at Arundel Senior High were found this week to have measles, said Evelyn Stein, a spokeswoman for the Anne Arundel County Health Department.
Immunization clinics will be held at the school next Monday and Tuesday, she said.
Students who haven't had a second measles vaccination, or who are unable to prove their immunity, will be barred from classes starting Wednesday.
Arundel authorities are also watching for outbreaks of measles at Annapolis and St. Mary's high schools in Annapolis, where individual cases have been reported. Immunization clinics will be organized if additional cases turn up, Stein said.
In Harford County, a team of nurses has scheduled visits to vaccinate about 1,900 sixth-graders this week and next, for students who have not received the recommended second dose.