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Multiple vaccines and combination vaccines

Date last reviewed: 
Tuesday, Mar 12, 2024

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Infants and young children receive many vaccines within their first 2 years of life and often receive multiple vaccines at the same appointment. This is to give them protection early in life before they come in contact with vaccine-preventable diseases and when they are at the highest risk of getting sick or dying if they get these diseases.

Multiple vaccines and your baby’s immune system

Some parents wonder if getting all the recommended vaccines will be too much for their baby's immune system. However, this is not the case. Vaccines do not overload a baby's immune system. Instead, they make it stronger by providing protection against diseases. Only a very small part of your baby's immune system is used for a short period of time, even when your baby gets several vaccines at once. Even combination vaccines, which protect against multiple diseases, are easy for your baby's immune system to handle. Theoretically, a baby's immune system could handle thousands of vaccines at the same time.
Vaccines contain killed, weakened, or synthetically manufactured versions of the disease-causing germ or parts of the germ called antigens. Some newer vaccines contain instructions that tell the body how to make the antigen. Antigens cause the body’s immune system to respond and build protection against disease. Every day, a healthy baby’s immune system successfully fights off millions of antigens (germs) they come across in their environment (in the air, food,  water, and on objects). Vaccines contain only a tiny fraction of the antigens babies encounter daily.
A Black man and woman holding a smiling baby.

Getting multiple vaccines at the same visit is safe

Getting multiple vaccines at the same visit is safe. It ensures your child is protected as quickly as possible during their early years when they are most at risk. Getting several vaccines at the same time also means fewer appointments and periods of pain and discomfort for your child, which may reduce your child’s risk of developing needle fears. 
Research shows that routine childhood vaccines work just as well when they are given at the same visit as when they are given at separate visits.

Combination vaccines are safe

Combination vaccines are made so that two or more vaccines that could be given individually can be administered as one injection. They reduce the number of shots needed while protecting against the same number of diseases. 
Combination vaccines are safe. Before a new combination vaccine is approved, it must be shown to be as effective as each vaccine given separately. Side effects of combination vaccines are similar to those of the individual vaccines given separately. 
Many of the vaccines available in combinations are not available separately. Therefore, if you turn down one component of the vaccine, all other components are also turned down. For example, refusing the measles vaccine means that a child cannot be immunized against rubella and mumps, either, because the measles vaccine in Canada is only available in combination with the mumps and rubella vaccines. 
Examples of combination vaccines: