CHULA VISTA -- Nine children have contracted chickenpox over the past month at a charter school in Chula Vista, and only one was properly vaccinated, county health officials reported Friday.
The illness broke out at the Dehesa Charter School Chula Vista Resource Center but is unrelated to another rash of cases at a school in San Diego reported last week, according to the county Health and Human Services Agency.
Those who were sickened range in age from 6 to 15.
The first student was reported ill on March 28 and the latest got sick on April 25. It takes two weeks or more for the disease to appear after exposure, so more children might get sick, according to the HHSA.
The school has notified students and staff about the outbreak.
"The best way to prevent chickenpox is to get the varicella vaccine," said Dr. Wilma Wooten, the county's public health officer.
"The vaccine is very safe and effective, and not only does it protect the person who is being vaccinated, it helps protect those who are unable to get the shot due to underlying medical conditions and who could become very ill if infected with chickenpox," Wooten said.
There have been 25 cases of chickenpox reported in San Diego County so far this year, the HHSA reported. Chickenpox is not reportable to county health officials unless there's an outbreak or an illness results in hospitalization or death.
The highly contagious disease is caused by the varicella virus and is easily spread by coughing, sneezing or being in contact with chickenpox blisters.
Symptoms include a skin rash of blister-like lesions -- covering the body but usually more concentrated on the face, scalp and trunk. The risk of complications increases after puberty and includes bacterial infection of skin lesions, dehydration and pneumonia.
Most, but not all, infected individuals have fever, which develops just before or when the rash appears. If exposed, people who have been vaccinated against the disease may get a milder illness, with less severe rash and mild or no fever. The illness lasts about 5-10 days.
The U.S. Centers for Disease Control and Prevention recommends two doses of chickenpox vaccine. Children should be vaccinated at 12-15 months of age and receive the second dose at 4-6 years of age.
More information on chickenpox and immunizations in general is available from the HHSA Immunization Branch at 866-358-2966, or online at www.sdiz.org.