What are some side effects of my child's vaccines?

Thomas Jacob, MD
Vaccines usually have mild side effects such as redness, swelling or soreness at the vaccination site. Your child may also develop low-grade fevers, which usually self-resolve. The varicella (chickenpox) vaccine has a low risk of causing a mini-chickenpox like illness 7-21 days after receipt, and the MMR (measles, mumps and rubella) vaccine can cause fever and rash 3-12 days after vaccination. More serious side effects following vaccination, such as severe allergic reactions, are rare. Make sure to let your pediatrician know immediately if your child is experiencing such symptoms.
“Based on word-of-mouth rumors, some parents believe that multiple vaccines overload the immune system, that preservatives in vaccines lead to brain damage or that measles, mumps and rubella (MMR) shots cause autism in children,” explains UCLA pediatric infectious disease specialist James Cherry, M.D. “Those beliefs are not supported by scientific evidence and have been repudiated by all reputable experts.”

The most common vaccines, according to Dr. Cherry, are safe and effective. The bigger dangers, he says, are complications or death from diseases that can be easily prevented by timely immunizations. Measles, for example, can cause pneumonia, brain inflammation and death; mumps can result in male infertility; and rubella in pregnant women can lead to premature birth, low birth weight or cardiac, brain, eye and ear defects in babies. Other highly contagious, vaccine-preventable diseases include pertussis (whooping cough), haemophilus influenzae B (HIB) and meningitis, which are particularly dangerous to infants and young children.
Any vaccine can cause side effects, but for the most part, they are minor. Some common side effects are pain at the sight of injection, fever, localized redness, and in rare cases an allergic reaction. Vaccines are always monitored for safety, and remember, a decision not to immune a child involves risk. Not immunizing children can put them, as well as other children in contact with them, at risk.
Vaccines are very safe but may have minor side effects. Your child may experience soreness at the injection site, have a mild fever, be slightly cranky, or even sleep a little longer than usual (enjoy this one) the day or two after some vaccines are given. Your pediatrician may recommend giving
an appropriate dose of acetaminophen or, if your baby is older than 6 months, ibuprofen prior to the vaccines and as needed later that day. Another common side effect from any shot is a small pea-sized lump under the skin at the injection site. This is not dangerous and will resolve over the next few weeks.

Risk of a serious side effect from a vaccine is very small compared with the risk of serious illness caused by catching the disease. There are countless medical studies that support the safety of vaccines and show that vaccines do not cause autism or any other childhood disease. Much parental concern has been focused on thimerosal, a mercury-based preservative. It is  important to know that thimerosal was removed from all childhood vaccines by 2001 as a precautionary measure. Therefore, none of the vaccines that your little one will get contain this preservative.

For more information on vaccines, speak with your pediatrician and visit the American Academy of Pediatrics and Centers for Disease Control and Prevention Web sites.
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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.