Home Vaccine Q & A Can a baby’s immune system handle more than one vaccine at a time?

Can a baby’s immune system handle more than one vaccine at a time?

by TheVaccineMom

Babies are exposed to numerous bacteria and viruses on a daily basis. Hands and objects enter those little babies’ mouths just about every minute, exposing their immune systems to antigens on a daily basis. Their immune systems are always working to fend off intruders.

Immune system cells are constantly hard at work. But it comes to vaccines, there is no evidence that combining vaccines can “overload” an infant’s immune system. And many studies have demonstrated that a baby’s immune system can handle receiving more than one vaccine at a time.

It has been shown that infants could receive more than the recommended amount of vaccines given at a time without compromising the immune system’s ability to respond appropriately. Babies’ immune systems are much stronger than you think. According to Adverse Events Associated with Childhood Vaccines, a 1994 report from the Institute of Medicine, based on the number of antibodies present in the blood, a baby would theoretically have the ability to respond to around 10,000 vaccines at one time!3 They even went so far as to say that even if all 14 childhood vaccines were given at once, only slightly more than 0.1% of the baby’s immune system capacity would be at work.

Both the Advisory Committee on Immunization Practices and the American Academy of Pediatrics actually recommend combination vaccines whenever they are available.  

The current infant vaccine schedule is based on the infant’s ability to generate the appropriate immune response. And although children are getting more vaccines than ever before, the vaccines that we use currently are far more efficient than those that were used when we were young. In fact, our children are exposed to fewer immunologic components in vaccines than we were.

Infants have enormous capacity to respond to multiple vaccines. Immune cells are constantly being replenished, and because of this, the immune system really doesn’t become overwhelmed. Instead, the immune system is strengthened by vaccines.

The antigens in vaccines are negligible in comparison to what our children are exposed to every day.

Rejoice in knowing that your child’s immune system can easily handle all these vaccines they’re given in the early years of life.

Here’s a great pamphlet from health.gov: Giving your Child More than One Vaccine at a Time


1. The History of Vaccines. Thehistoryofvaccines.org

2. Centers for Disease Control and Prevention. www.cdc.gov

3. Adverse Events Associated with Childhood Vaccines, a 1994 report from the Institute of Medicine

4. Public Health. www.publichealth.org

5. Paul A. Offit, Jessica Quarles, Michael A. Gerber, Charles J. Hackett, Edgar K. Marcuse, Tobias R. Kollman, Bruce G. Gellin and Sarah Landry. Addressing Parents’ Concerns: Do Multiple Vaccines Overwhelm or Weaken the Infant’s Immune System? Pediatrics 2002;109;124-129 DOI: 10.1542/peds.109.1.124

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