ASK THE DOCTOR: COULD THE FLU SHOT HAVE MADE MY 3-YEAR-OLD SICK?

Q: I'm confused about the flu shot. My 3-year-old got one last week and within 24 hours he spiked a fever of 102 and a cough. He was diagnosed two days later with pneumonia. He had no allergy or cold symptoms when he got the shot. Could the pneumonia have been caused by the shot? Or could getting it have compromised his immune system? Could he have just gotten a bug by going into the doctor's office?

A: People want to know that if they are vaccinated to prevent a serious illness like influenza that the vaccine will be safe and effective without risk of serious complications. Because the vaccine is made with dead virus (inactivated), no one can develop the disease from it. Many people have heard of symptoms following the administration of flu vaccine, but these last only one to three days and are minor, such as a low-grade fever, achiness, or redness or swelling at the injection site. The symptoms you describe above - high fever, cough and pneumonia - are likely the result of a previous exposure and are not related to the flu shot.

It is possible to contract a virus or bacteria from other people when in confined spaces, including stores, mass transit, and even offices. Symptoms can develop within one day to one week. Germs are spread easily when someone coughs or sneezes, and then another person touches a surface infected with the germs of that cough or sneeze, and then touches his or her nose, mouth or eyes. The best way to protect your child from exposure to germs in public places is to teach the importance of hand washing. It takes 15 seconds of scrubbing with soap and warm water to kill bacteria and viruses. A good way to help make sure your child washes for long enough is to sing the Happy Birthday song through twice.

You asked if your child's immune system might have been compromised from the vaccine. Rest assured that vaccines do not reduce the immune system. Rather, vaccines trigger immune response in the body. It is in this manner that we can protect ourselves by using key parts of the killed influenza virus to develop heightened immunity to the flu virus. Keep in mind, though, that the vaccine becomes effective around two weeks after it is given, so there is a window after the flu shot when the protection the vaccination affords has not yet kicked in.

Influenza is found all over the world at one time or another during the year. In the United States we see most cases in the winter between November and April. Once infected, children and adults can develop fever, headache, sore throat, a severe cough and body aches that can last a week to 10 days. Fortunately, through vaccination we can prevent or reduce the severity of this illness, which can kill or incapacitate infants, the aged and others at high risk. Newer versions of the influenza vaccine use weakened parts of the influenza virus and are administered through nasal passages instead of being injected. This imparts a stronger immunity because of this method. Children as young as 2 are now eligible to receive it. Some insurers are not covering the nasal flu vaccine, and it isn't appropriate for everyone, so discuss this with your doctor if you have any questions. Most offices have adequate supplies of flu vaccine this year, but it varies by office and region. I always advise my patients not to wait until flu season starts to get the flu vaccine, but if you have waited, it's not too late. The vaccine can be given through the season into the spring.