Which vaccines are recommended for a 13-year-old female who has received only one dose of measles‑mumps‑rubella (MMR) vaccine, one dose of varicella vaccine, and a third dose of inactivated polio vaccine (IPV)?

Vaccines Needed for This 13-Year-Old

This 13-year-old needs: (1) a second dose of MMR, (2) a second dose of varicella vaccine, and (3) potentially a fourth dose of polio vaccine depending on when the third dose was given.

MMR Vaccine (Second Dose Required)

The patient has only received one dose of MMR and requires a second dose to complete the series. Two doses of MMR vaccine are required for all individuals, with the second dose administered at least 4 weeks after the first dose 1. Since this patient is 13 years old and has only one documented dose, she needs her second MMR dose now.

• The standard schedule recommends the second dose at age 4-6 years, but catch-up vaccination is appropriate at any age 1
• The minimum interval between doses is 4 weeks, so as long as more than 4 weeks have elapsed since her first dose, she can receive the second dose immediately 1, 2
• No need to restart the series regardless of time elapsed between doses 1

Varicella Vaccine (Second Dose Required)

For persons aged ≥13 years, two doses of varicella vaccine are required, administered at least 4 weeks apart 3, 4. Since this patient is 13 years old with only one documented dose, she needs a second dose.

• For children who received their first dose before age 13, the minimum interval is 3 months 1, 5
• However, since she is now 13 years old, the adolescent/adult schedule applies: minimum 4-week interval 3, 6, 7
• If the first dose was given more than 4 weeks ago, she can receive the second dose immediately 3, 7

Polio Vaccine (Fourth Dose May Be Needed)

A fourth dose of IPV is not necessary if the third dose was administered at age ≥4 years and at least 6 months after the previous dose 1, 5.

Critical decision point: You must determine when the third polio dose was given:

• If the third dose was given at age ≥4 years: No fourth dose needed 1
• If the third dose was given before age 4 years: A fourth dose is required now 1, 5, 8

The guideline explicitly states that for children who received an all-IPV series, a fourth dose is not necessary if the third dose was administered at age ≥4 years 1.

Additional Vaccines to Consider

While not explicitly mentioned in the question, a comprehensive catch-up schedule for a 13-year-old should also assess:

• Tdap vaccine: Recommended at age 11-12 years if not previously given 1
• HPV vaccine series: Recommended for females age 13-18 years if not previously vaccinated 1
• Meningococcal conjugate vaccine (MCV4): Recommended at age 11-12 years 1
• Hepatitis B series: If not previously completed 1
• Annual influenza vaccine 1

Common Pitfalls to Avoid

• Do not restart vaccine series: Regardless of time elapsed between doses, continue from where the patient left off 1, 5
• Age-specific intervals matter: The varicella vaccine interval changes at age 13 (from 3 months to 4 weeks minimum) 3, 5
• Verify polio dose timing: The decision about a fourth polio dose hinges entirely on whether the third dose was given before or after age 4 years 1, 5
• Multiple vaccines can be given simultaneously: MMR and varicella can be administered at the same visit using separate syringes at separate sites 1