AGOURA HILLS (CBSLA.com)    —  Nearly 100 students of an Agoura Hills elementary school have been ordered to stay home while the school deals with an outbreak of chickenpox.

CBS 2’s Amy Johnson spoke to concerned — and angry — parents Friday.

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Ninety of the nearly 400 students of  the Mariposa School of Global Education are out because they haven’t been vaccinated. And they have been told to stay home for three weeks because three classmates have come down with the very contagious illness.

“I think it’s absurd. I really really do,” says parent Nikie DesRoches.

Her 5-year-old daughter, Cozy, has been banned for 21 days because she was not vaccinated .

“I personally believe that vaccines don’t work” says DeRochas, ” I think they are more dangerous than anything.  I feel like we are not a threat to the school.”

“There were three  cases of chicken pox,” says school superintendent Daniel Stepenowsky, “A kindergartener, a first-grader, a third-grader. The first case happened around mid-March. The student was immunized, however still contracted chickenpox.”

Stepenowsky is the superintendent of the Las Virgeness Unified School District.

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“Given that there were three cases, given that they were in three different grades, the health department gave the directive to exclude students who are not immunized.”

Calls went out to the parents of the un-vaccinated students last Friday to begin the 21-day leave order. And letters went out to all other parents at the school including Bruce Zucker.

“I think the science is very clear,that vaccinations are good and not bad,” Zucker said.

The banned students are involved in an independent study  and are receiving school work packets so they don’t fall behind while they avoid or possibly spread the very contagious illness.

“Vaccination is the best way to prevent chicken pox,” says Dr. Tanya Altmann, “there is still a small chance that you can catch chicken pox after the vaccine.However, it is usually a much more mild case with fewer chances for serious infection.”

Cozy has a medical excuse from getting immunizations after an adverse reaction. Her mom says she misses her friends and wants to be at school.

“I had chicken pox I survived it. I’d would much rather her get it at  a young age than an older age,” said DeRochas.

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A new law prevents religious beliefs as an excuse not to get vaccinated- but it’s important to mention schools only check for immunizations when a child is entering the school at kindergarten or seventh grade. So kids in first thru sixth grade don’t have to prove they’ve been vaccinated.