Some Maryland students were sent home from school this week while thousands more face a dwindling grace period to get up to date on chickenpox and hepatitis B vaccinations.
New regulations, which affect mostly sixth- through ninth-graders, included a Jan. 1 deadline that required schools to exclude those who have not received the vaccines or, in the case of chickenpox, have not documented when they had the illness.
Many students are taking advantage of a 20-day window in which they can attend classes if they show they have an appointment to get their shots. After Jan. 20, students in kindergarten through ninth grade who are not immunized will have to stay home, although most students through fifth grade were covered under previous requirements.
Excluded students may return as soon as they get the vaccinations, said Greg Reed, program manger at the state Department of Health and Mental Hygiene's Center for Immunization.
"All 24 of our local health departments are putting in an extra amount of time and effort to do back-to-school clinics," he said, including ones in the evenings, on weekends and, in some cases, at the schools.
"We're coming down toward the end," Reed said. "The efforts still continue and will continue through the rest of this month."
After months of letters, calls, visits, advertising and one-on-one conversations by school staffers, 55,000 middle- and high-school students statewide had not met the requirements going into the winter break.
State officials say they do not have a current count, but Baltimore-area schools report the number of noncompliant students is falling.
About 4,000 students in Harford County and 8,536 in Baltimore City had not complied with the regulations, school representatives said yesterday. In Baltimore County, the number was estimated to be below 2,300.
Those school systems and others in the state are using the 20-day extension period liberally and plan to start excluding students only after Jan. 20.
Carroll County is among those interpreting the law more strictly.
"If they have not had the immunizations, but they have made the effort to have the appointment, then according to the law, we can allow them to be in class," said Marge Hoffmaster, supervisor of health services for the school system.
She said 100 students were sent home Tuesday, and more than 50 returned yesterday.
In Anne Arundel County, where 659 students remained without proof of immunization yesterday, and in Howard County, where the number was about 800, some students were sent home, but hundreds were coming up with the needed documentation this week.
"Certainly we're pleased that the number is declining," said Tony Ruffin, an Anne Arundel school system spokesman. "Our ultimate goal is to have every student in compliance, and that means we need to continue to work with the Health Department and within our own schools to make sure parents are completely aware how important this issue is."
Almost two years ago, the General Assembly decided that students should get up to speed on the chickenpox (also called varicella) and hepatitis B vaccines quickly. Usually, vaccination regulations are phased in over many years with efforts aimed at the youngest children.
This time, the need for older students to go out and get new vaccinations proved a challenge.
"We realized when the General Assembly asked the state Health Department to do this that it would require a great deal of work from all our partners," Reed said. "We do think it's going to be worth it. There are thousands and thousands of children who will be protected against two diseases that can have some rather serious implications for them as they go on to adulthood."
Health experts agree that there are good reasons for requiring vaccinations against chickenpox and hepatitis B.
In the case of chickenpox, vaccinating children prevents them from getting sick and prevents them from spreading the disease to adults, for whom the disease poses more serious health risks.
"As you get older, chickenpox gets worse," said Dr. Anthony Caterina, an Owings Mills pediatrician and a fellow with the American Academy of Pediatrics.
Chickenpox poses a particular threat to the elderly or those who are sick and have weakened immune systems, according to Caterina and other experts.
Left untreated, it can develop into pneumonia and lead to other complications in newborns and pregnant women, they say.
"It's a very infectious disease," said Dr. James King, a researcher and professor of pediatrics at the University of Maryland School of Medicine who treats children at the University of Maryland Medical Center's pediatric clinic.
Vaccinating against chickenpox also reduces the risk of outbreaks and cuts back on absenteeism among children and parents who have to stay home and care for them, Caterina said.
Many children were vaccinated before the start of school last fall, pediatricians say. Now, it's mostly middle and high school students. Grade school students have been vaccinated as a result of programs started in the 1990s.
"We've had a big influx in our clinic of parents asking for varicella [chickenpox] vaccinations," King said. "I wouldn't say we've been inundated, but we've seen a very large increase in parents."
The new regulations mean that health officials are not accepting statements of recall about child vaccinations from parents. They are requiring a doctor's verification that a child had chickenpox, or proof of vaccination -- and thousands of children have neither, King said.
"We've had groups of kids whose mothers say they had chickenpox, but what do you do with that?" King said. "What we've been doing is going ahead and vaccinating them."
Chickenpox is spread through personal contact when lesions on the skin dry and the virus becomes airborne, experts say.
Most adults have had chickenpox as children, King said. But because of vaccination programs, started in Maryland and elsewhere in the 1990s, there is a small population that hasn't had chickenpox and is at risk.
Hepatitis B is a blood-borne disease that can be passed on by high risk behavior such as having unprotected sex or intravenous drug use, King said. Left untreated, hepatitis B can cause liver damage, liver cancer and even death.
The vaccine, available in the United States for more than two decades, is highly effective, health officials say.
Sun reporters Liz Bowie, Arin Gencer, Mary Gail Hare, John-John Williams IV, Gina Davis and Sara Neufeld contributed to this article.