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Reporting a Medication Error

Mix-Ups Between Doses of Children and Adult Vaccines

Published June 6, 2024

Vaccines come in different doses for children and adults. Sometimes a mix-up happens in which a child may get an adult dose, or an adult may get a child’s dose. Vaccines that combine multiple products into one (combination products) are more likely to be involved in a mix-up. For example, the combination vaccines against diphtheria, tetanus, and pertussis (whooping cough) often get mixed-up because they come in different strengths There is strength one for children (DTaP) and one for adults (Tdap).

Both strengths use the same letters to form an abbreviated name. However, upper- and lowercase letters are used to indicate the different strengths. Babies and children (up to age 7) need the higher-strength vaccine (DTaP) to build their immune systems. The letters D, T, and P are capitalized to indicate a higher strength of diphtheria, tetanus, and pertussis in the vaccine for children. Older children and adults who need a booster shot of the vaccine, will receive a lower-strength version known as Tdap. The lowercase letters, d and p, indicate a lower strength of diphtheria and pertussis used in this vaccine. The lowercase “a” in the vaccine names stands for "acellular," which means that the whooping cough (pertussis) portion of the vaccine only contains parts of the bacteria rather than the whole bacteria.

Children under 7 who accidentally get Tdap instead of DTaP would not receive enough of the vaccine to build up their immune system. Adults who receive the higher strength would get more than required.

Here's what you can do: Many doctor's offices, clinics, and pharmacies carry vaccines for both age groups, so mix-ups can occur. If you or your child are getting vaccinated, consider the following:

  • Know the name of the vaccine you need. The Centers for Disease Control and Prevention (CDC) provides vaccination (immunization) schedules for children and adults. The schedules recommend which vaccine should be given based on the person’s age. Some vaccines need to be given multiple times to build up immunity. And older children and adults sometimes need a booster to maintain immunity. You can use these schedules to see if you or your child are receiving the right vaccine at the right time.
  • Ask your healthcare provider to check you or your child’s vaccine records. Healthcare providers should verify what vaccines have previously been given prior to vaccination. Some states maintain vaccine administration records in a registry. You can check to see if your state has a vaccine registry by contacting your State Health Department. If you need additional tips finding your vaccine records, visit:
  • Read the Vaccine Information Statement (VIS). A Vaccine Information Statement (VIS) is a handout that provides important information about the vaccine you are going to receive. Healthcare providers are required to give you a VIS before administering the vaccine. You can also download and print any VIS from the CDC’s website. Be sure to read the VIS and ask any questions before you receive the vaccine.
  • Confirm the vaccine is correct. Before accepting any vaccine for you or your child, ask the nurse or doctor to show you the vial they used to draw up the vaccine or the prefilled syringe. Confirm the vaccine name on the vial or syringe is the correct.
  • Confirm your or your child’s identity. Make sure the healthcare person confirms you or your child’s name and date of birth before they administer the vaccine.
  • Keep a vaccine record. It is important to keep a record of the vaccines you and your child have received. After each vaccination, make sure to update it. Bring the updated list to every vaccination appointment.

For more information on ways to prevent errors when receiving vaccines, visit: Preventing Errors When Receiving Vaccines.

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