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Kids and the Immune System


“Our immune system is a series of cells, tissues and organs that, throughout our lifetime, protects us from different invading pathogens and keeps us healthy and able to resist many repeated infections,” says Dr. Ashouri, a pediatric infectious disease specialist at CHOC. “When babies are infants, they get immune cells from mom through the placenta and breast milk, if they are breastfeeding. Over time, the baby’s system becomes mature and can fight off infections. A healthy lifestyle that includes getting enough rest, low stress and a balanced diet plus exercise helps to strengthen the immune system in people of all ages.”


“Breastfeeding is probably one of the best ways to help support a baby’s immune system when it’s developing,” explains Dr. Ashouri. “Getting babies the recommended vaccines at the scheduled times also helps to protect them from the different infections they are at risk for at that age. We recommend that parents and children also get a flu shot each year and are up-to-date with their Tdap vaccine to protect kids from pertussis (whooping cough). The
more people in the community who are vaccinated, the better it is for everyone. In pockets of areas where vaccine rates have fallen, there have been outbreaks of measles, whooping cough and other preventable diseases.”


“Proper hand-washing is important to prevent the spread of colds and the flu virus and other types of infections. When kids can’t wash their hands, they should use a hand sanitizer to kill germs. Getting kids vaccinated against the flu also prevents kids from getting the flu,” Dr. Ashouri says. She adds, “Over time as the immune system recognizes certain viruses, it will get better at preventing infection, especially if the person has a balanced diet and good lifestyle. Taking vitamins won’t hurt either but they don’t replace a well-balanced diet.”


  • Number of infants who died in California’s 2010 Pertussis (Whooping Cough) outbreak. It was the worst outbreak in 60 years.
  • More than 9,000 cases were reported: 10
  • Percent of the U.S. population that gets the seasonal flu (Influenza) each year: 5 to 20
  • Number of children hospitalized in the U.S. each year with respiratory infections: 500,000

Meet Dr. Ashouri - CHOC Pediatric Infectious Disease Specialist

Dr. Negar Ashouri completed her residency at CHOC, followed by a year as chief resident. After completing a fellowship in pediatric infectious diseases at Children’s Hospital of Los Angeles, she returned to CHOC. She is also a clinical instructor of Pediatrics at the UC Irvine School of Medicine.

Dr. Ashouri is involved in many research projects dealing with bloodstream infections and drug trials. She is also part of the Collaborative Antiviral Study Group. To further her research, Dr. Ashouri maintains an ongoing database of blood cultures and can frequently be found looking back through patient data and charts as she investigates how vaccines impact infections and specific risk factors for high-risk groups.

St. George’s University School of Medicine, Grenada, West Indies

Pediatric Infectious Disease

Dr. Negar Ashouri

A Parent’s Guide to Antibiotics

When a child gets sick, parents may be surprised if the pediatrician isn’t quick to pull out the prescription pad for an antibiotic.

Most seasonal illnesses like respiratory infections, the flu and the common cold are actually viral infections, for which antibiotics have no effect.

Physician with patient and parents in exam room

Different Kinds of Infections

In this video from the American Health Journal program Dr. Katherine Andreeff talks about the difference between bacterial and viral infections. Patient history and physical examinations are sometimes not enough to determine whether an infection is viral or bacterial, Dr. Katherine Andreeff, a hospitalist at CHOC, tells “American Health Journal.” In these cases, blood work and imaging may be required to make an accurate diagnosis, says Dr. Andreeff. Hand-washing and vaccination can help prevent infections, whether bacterial or viral. For more information, go to

How Effective are Hand Sanitizers

Though old-fashioned hand-washing is the best way to keep hands clean and combat germs, gel hand sanitizers are a good alternative when soap and water aren’t readily available.

“They certainly don’t take the place of proper hand-washing,” says Dr. Negar Ashouri, a CHOC infectious disease specialist.

Mom helping son sanitize his hands

Knowledge is the best medicine. Learn more about your child's health in these features from the experts at CHOC.

Kids and Ear Infections
An ear infection is an acute inflammation of the middle ear caused by fluid and bacteria behind the eardrum. These ear infections cause a great deal of pain.

Kids and Healthy Hearts
People who don't have heart problems as kids may develop them as adults. One risk factor is obesity. Physical activity is an easy way to get healthy hearts.

Kids and Autism
Autism spectrum disorders are typically diagnosed in toddlers or young children based on certain behavioral patterns; there is no medical diagnostic test.

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