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News & Views: Combination Vaccines and the Catch-up Schedule

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News & Views: Combination Vaccines and the Catch-up Schedule
June 25, 2024

It’s been a busy day of visits. You take a minute to sip some water and open the next child’s chart as she is getting settled into a room. You know this family well. They had initially asked to space out vaccinations and have only received one dose of DTaP, the entire pneumococcal series, and a single dose of varicella vaccine. With school starting in the fall, they are now eager to get their 4-year-old daughter caught up on all recommended vaccines. You take a deep breath. You spent time planning a catch-up schedule last week in anticipation of today’s visit and knowing the work that goes into the planning, particularly for a child who is partially vaccinated, you are hoping that the visit goes smoothly. 

Determining which vaccines are needed

For the most part, an electronic health record (EHR) can do the heavy lifting, indicating which vaccines are due (or overdue) for a patient. In the above scenario, using the child’s age and vaccines received to date, either an EHR or the CDC catch-up schedule will provide a list of vaccines recommended for this child, including hepatitis B (hep B), DTaP, Haemophilus influenzae type b (Hib), polio (IPV), MMR, varicella, hepatitis A (hep A) and COVID-19.

The child will also need two doses of influenza vaccine in the fall since she is younger than 9 years of age and has not previously received any doses.

Making a catch-up plan

After generating a list of vaccines that the child needs, it is time to devise a schedule to get them started before school begins in the fall. One tool that can help is combination vaccines, which may simplify the catch-up process, reduce the number of injections, and possibly decrease the number of visits, thereby improving adherence.

Using combination vaccines

Unfortunately, EHRs often fall short when it comes to suggesting combination vaccines. If your EHR is among them or if you are figuring out a plan for this child manually, you might find the “Pink Book” to be of help. An appendix in this free online publication offers a comprehensive table on combination vaccines.

Two considerations arise when using combination vaccines in a scenario such as described above, where the schedule is non-standard or the family is hesitant about vaccines:

  1. If a combination vaccine contains a component that the child already received, but it otherwise meets the patient’s needs, it is OK for them to get the additional antigen.
  2. Families can be reassured that combination products have been demonstrated to be safe and effective in the combination being administered.

For our patient, some combination options include:

  • MMRV, which includes MMR-varicella (chickenpox)
  • Vaxelis, which includes Hep B-DTaP-Hib-IPV
  • Pediarix, which includes DTaP-HepB-IPV
  • Pentacel, which includes DTaP-IPV-Hib

Regardless of whether we use any of the above combination vaccines, hep A and COVID-19 will need to be administered as individual vaccines. Likewise, depending on which of the above options are used, the child will need stand-alone Hib (if giving Pediarix) or hep B (if giving Pentacel).

Mapping out the plan

Deciding which vaccines to use for a patient will, in part, be informed by which ones your location stocks, but a few general recommendations are also important to consider:

  1. Generally, receiving all vaccines from the same manufacturer allows patients to build a consistent immune response to a pathogen. When faced with multiple options, this should be considered. That said, best practice is to give whatever product is available at the time of the visit so that development of protection is not delayed. If only one option is available, it is better to get the child vaccinated than to delay.
  2. Two vaccines require consideration when using different manufacturers. For any DTaP-containing vaccine, efforts should be made to use the same manufacturer throughout the series. This may influence the selection of a combination product. Likewise, if giving Hib vaccine from different manufacturers, the number of doses required should be based on whichever product requires more doses.
  3. Although it would not apply in the scenario described above, when the manufacturer of prior doses is not known, patients can receive whichever product is available. 
  4. It is important to account for previous vaccinations by ensuring that the minimum interval is met for any previous vaccines before giving a combination product.  
  5. Since certain combination vaccines have age restrictions, they may not be able to be used even if the child is due for both antigens. For example, Twinrix (hep A-hep B) can only be used for people 18 years of age and older. Likewise, although a combined COVID-19 and influenza vaccine is likely in the future, it is unclear for what age groups it will be recommended.

Whether using combination or individual vaccines, another consideration when devising a catch-up plan is the number of doses needed in a series. In some cases, a particular brand might require fewer doses, allowing for faster completion of the plan and perhaps fewer visits. For example, in the current scenario, using the Moderna COVID-19 vaccine would decrease the number of shots and the length of time until the child is considered protected.

In the current scenario, this child has had a varicella vaccine, so she can’t get MMRV unless at least 12 weeks have passed since that dose. After confirming that the minimum 12-week interval has been met for varicella, you devise a plan that includes MMRV, Vaxelis, hep A, and COVID-19 (Moderna) for the first visit.

This patient’s full schedule will take seven months to complete from the first visit with the following plan:

Visit 2

  • Return date: 4 weeks after initial visit
  • Coverage needed: DTaP (dose #3), IPV (dose #2), hep B (dose #2), MMR (dose #2, final) and COVID-19 (dose #2, final)
  • Vaccines recommended (4 or 5 shots):
    1. Pentacel (DTaP-IPV/Hib) or stand-alone doses of DTaP and IPV — Either allows the child to receive the same manufacturer of DTaP; utilizing Pentacel will provide an additional antigen (Hib) while using two stand-alone products adds an extra shot. 
    2. MMR — Since the child had an earlier dose of varicella, only MMR is required.
    3. Hep B.
    4. COVID-19 — Second of the two-dose series.

Visit 3

  • Return date: 12 weeks after visit 2
  • Coverage needed: hep B (dose #3, final), influenza (dose#1)
  • Vaccines recommended (2 shots): stand-alone hep B and influenza vaccines

Visit 4

  • Return date: 4 weeks after visit 3
  • Coverage needed: influenza (dose #2, final)
  • Vaccines recommended (1 shot): influenza

Visit 5

  • Return date: 6 months after visit 2 
  • Coverage needed: DTaP (dose #4, final), IPV (dose #3, final), hep A (dose #2, final)
  • Vaccines recommended: (2 or 3 shots) Hep A and either Pentacel (DTaP-IPV/Hib) or stand-alone doses of DTaP and IPV. Hep A will be spaced seven months from the first dose instead of six months. This may be preferable to the family rather than coming in earlier for a single dose. Additionally, the family will again have the option of a single shot for Pentacel with an extra dose of Hib or an extra shot if giving DTaP and IPV separately. 

Talking with the family

When talking with families, it is important to recognize that there is not a single approach to designing a catch-up schedule, so providing strong recommendations as well as the rationale behind those recommendations will be helpful in moving families toward acceptance. Likewise, it is important to understand the family’s priorities and concerns. In this case, knowing that they are moving forward because of school requirements and speaking from that point of agreement will reassure the family that they have been heard.

In a scenario like the one above, it will be important to discuss the overarching plan and timeline, so the family knows what to expect. Plan to discuss the choices that families will have, such as discussing whether they prefer the use of Pentacel with an extra dose of Hib or giving two separate shots for DTaP and IPV during visits 2 and 5. Another choice will be whether the family prefers to come in before visit 5 to receive hep A vaccine or get it during visit five. These choices are important to offer to families, if possible, because they provide opportunities for parents to be involved in the decision-making process. Likewise, always ensure that families have opportunities to ask questions, and during each visit, remember to review any adverse events that require monitoring, such as the fact that both MMRV and Pediarix (DTaP-HepB-IPV) cause fevers more frequently than if the vaccines were given separately. Continuing to share the science behind the catch-up schedule and combination vaccines with your strong recommendation can provide the family with the information and reassurance needed to stay the course.

As you get ready to head into the exam room, you glance over the catch-up plan one more time. Hopefully, the family agrees to move forward, so you can rest assured that one more patient has been protected by these life-saving tools called vaccines.

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