What is the recommended vaccination schedule for a 15-year-old with no prior vaccination history for Measles, Mumps, and Rubella (MMR) vaccine, Diphtheria, Tetanus, and Pertussis (DTaP) vaccine, and polio vaccine?

Vaccination Schedule for an Unvaccinated 15-Year-Old

For a 15-year-old with no prior vaccination history, administer a 2-dose MMR series with doses separated by at least 4 weeks, a 3-dose Tdap/Td series (with the first dose being Tdap), and a 3-dose IPV series—all of which can be initiated simultaneously at the first visit. 1

MMR Vaccine Administration

Administer 2 doses of MMR vaccine during any visit, with a minimum interval of 4 weeks between doses. 1 This catch-up schedule applies regardless of the patient's current age, as there is no need to restart a vaccine series regardless of the time elapsed. 1

• The MMR vaccine can be given intramuscularly or subcutaneously as a 0.5 mL dose. 2
• Both doses should be administered as soon as possible to provide protection against measles, mumps, and rubella. 1
• MMR can be administered simultaneously with other vaccines at different anatomic sites. 1

DTaP/Tdap Administration

At age 15, this patient should receive Tdap (not DTaP) as the first dose, followed by Td for subsequent doses. 1 DTaP is only licensed for children and is not appropriate for adolescents aged 15 years.

Tdap/Td Series Schedule:

• First dose: Tdap vaccine immediately 1
• Second dose: Td vaccine at least 4 weeks after the first dose 1
• Third dose: Td vaccine 6-12 months after the second dose 1

The minimum age for Tdap (ADACEL) is 11 years, making it appropriate for this 15-year-old. 1 After the initial Tdap dose, subsequent doses should be Td to complete the primary series. 1

Inactivated Poliovirus Vaccine (IPV) Administration

Administer a 3-dose IPV series with the following schedule: 1

• First dose: IPV immediately
• Second dose: IPV at least 4 weeks after the first dose 1
• Third dose: IPV 6-12 months after the second dose 1

For adolescents who received an all-IPV series, only 3 doses are required if the series is started at this age. 1 A fourth dose is not necessary if the third dose is administered at age ≥4 years, but since this patient is starting from zero, a standard 3-dose series is appropriate. 1

Simultaneous Administration

All three vaccines (MMR, Tdap, and IPV) can and should be administered simultaneously at the first visit. 1 This approach:

• Does not interfere with immune responses to any of the antigens 1, 3
• Reduces the number of clinic visits required 1
• Improves vaccination completion rates 1
• Administers inactivated vaccines (Tdap, IPV) with live vaccines (MMR) without any required interval 1

When administering multiple vaccines simultaneously, use different anatomic sites for each injection. 1

Important Clinical Considerations

Minimum Intervals

• Between MMR doses: ≥4 weeks (28 days) 1
• Between first and second Tdap/Td doses: ≥4 weeks 1
• Between second and third Td doses: ≥6 months 1
• Between first and second IPV doses: ≥4 weeks 1
• Between second and third IPV doses: ≥6 months 1

Common Pitfalls to Avoid

• Do not use DTaP for adolescents: DTaP is only licensed for children; Tdap must be used for the first dose in adolescents, followed by Td. 1
• Do not delay vaccination: There is no need to space out these vaccines over multiple visits unless medically contraindicated. 1
• Do not restart the series: If the patient misses appointments, continue from where they left off rather than restarting. 1

Documentation and Follow-Up

Ensure the patient returns for:

• Second MMR dose at 4 weeks after the first dose 1
• Second Td dose at 4 weeks after Tdap 1
• Second IPV dose at 4 weeks after the first dose 1
• Third Td and IPV doses at 6-12 months after the second doses 1