SAN DIEGO -- The San Diego County Health and Human Services Agency (HHSA) reports that nine students at Dailard Elementary School in the San Diego Unified School District and 9 students at National City Middle School in the Sweetwater Union School District have been diagnosed with chicken pox (varicella).

All nine of the students at Dailard Elementary had at least one dose of chicken pox vaccine. Five of the nine at National City Middle School had one dose of vaccine, and four had no dose of vaccine. Parents are reminded that two doses of vaccine are recommended.

“We urge parents to check with their physicians to make sure their children get two doses of chicken pox vaccine when appropriate, and are inoculated against other vaccine-preventable diseases,” said Wilma Wooten, M.D., M.P.H., County Public Health Officer.

Chicken pox is a highly contagious disease caused by the varicella virus. The disease is easily spread by coughing, sneezing or contact with chicken pox blisters. The Centers for Disease Control and Prevention recommends two doses of chicken pox vaccine for all people 1 year of age and older who do not have evidence of immunity for the disease. Officials said 99-percent of people develop immunity after two doses.

None of the students, kindergarten to fifth-graders at Dailard Elementary, and seventh-graders at National City Middle School, required hospitalization. School officials have informed parents about the outbreak and asked them to make sure their children have had the appropriate vaccinations against the disease, county health officials said.

Symptoms of chicken pox 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, persons who have been vaccinated against the disease may get a milder illness, with less severe rash (sometimes involving only a few red bumps that look similar to insect bites) and mild or no fever. The incubation period is from 14-16 days from exposure, with a range of 10-21 days. The illness lasts about five to ten days.

For more information on chicken pox and immunizations in general, please call the HHSA Immunization Branch at 619-692-8661 or visit the website at www.sdiz.org.