News & Views: Are You Using This Resource? See What Your Colleagues Are Asking.

Many of you may be aware that the Vaccine Education Center (VEC) offers a free mobile app, Vaccines on the Go, for both Apple and Android devices, and we know that you share this resource with your patients and their families frequently (Thank you!) But … are you aware that you can email us questions directly from the app? Some of your colleagues are, and they use this easy access to the VEC team to send their quick-check, or more perplexing, vaccine-related questions our way. Check out a sample of questions that we have received from your colleagues and how we answered them (edited for length and clarity).

If a child (aged 5 years old) has a history of ITP (secondary to flu vaccine about 1-2 years ago), should they get the COVID-19 vaccine?

History of idiopathic thrombocytopenic purpura (ITP) is not a contraindication to receipt of COVID-19 vaccine.

If a 4-year-old comes in and gets first dose of Pfizer’s COVID-19 vaccine, then turns 5 before getting the second dose. What is the recommendation?

The CDC has provided clear guidance for the transition ages for COVID-19 vaccination. They developed these helpful documents to summarize the guidance:

• Pfizer
• Moderna

I have a healthy 13-year-old patient with a solitary kidney. His family is concerned about him getting the COVID-19 vaccine. It seems like a much better idea for him to get the vaccine than to get infected if the goal is to protect the solitary kidney. Are you aware of any adverse renal events with the Pfizer vaccine?

We agree with your assessment that vaccination is the safer choice for this patient if he does not have other characteristics that would preclude his receipt of the vaccine. COVID-19 infection affects a variety of systems and organs, including the kidneys. On the other hand, negative effects of COVID-19 vaccination on the kidneys have not been reported, nor would they be expected since the vaccine is processed locally in the lymph nodes near the site of vaccination.

Any downside to the use of Vaxelis hexavalent vaccine?

Vaxelis^® contains vaccines to prevent diphtheria, pertussis, tetanus, polio, Haemophilus influenzae type B (Hib) and hepatitis B. The doses contained in Vaxelis are slightly different, with lower quantities of polio and Hib compared with Pediarix^® and PedvaxHIB^® and a higher quantity of hep B compared with Recombivax HB^®. However, noninferiority and concomitant use studies found similar antibody responses and side effects profiles with three exceptions:

• Lower responses to the FHA pertussis antigen for one of two trial endpoints
• Lower responses to one of 13 pneumococcal serotypes when given together (type 6B); however, the clinical significance of this is unclear
• Higher rate of fevers (about 47% vs about 33%-34%), but no increase in fever-related hospital visits or febrile seizures

Data are still needed to determine whether there will be a preference for this product among American Indian/Alaska Native babies as there is for PedvaxHIB.

So, in sum, Vaxelis offers the benefit of one less shot at the 2-, 4-, and 6-month visits without any significant known downside (other than about 10-15 of 100 additional kids will experience fever).

CDC now says we can use either PCV13 or PCV15. Any preference?

In healthy kids, immune responses for the 13 shared types were all similar in one study and with two exceptions in another:

• One noninferiority measure was not met (for serotype 6B)
• PCV15 induced significantly greater immunity for one other type (serotype 3)

In kids with conditions that increase their risk (e.g., sickle cell and HIV), responses were similar or better following PCV15. However, if a child needed PCV13/15 and then PPSV23, the responses to the two unique strains in PCV15 were lower using the PCV15-PPSV23 regimen compared with the PCV13-PPSV23 regimen; however, no concerns about clinical significance were mentioned in the recommendations.

The two additional types account for significant numbers of ear infections (9% of pneumococcal-caused cases are by types covered in PCV13 and 8% additional cases are covered by the two unique types in PCV15) and invasive disease (unique types in PCV15 cover an additional 15% and 23% of cases in the < 5yo and 5-18yo, respectively). Given this, and the equivalent or better immune responses as well as similar safety profiles, the use of PCV15 instead of PCV13 makes sense.

If a patient got the first Varivax then had a clinical breakthrough varicella infection before the second dose, do you think they should get the second dose?

Please see the below answer from Immunize.org’s “Ask the Experts” as they address a similar situation. Since we were uncertain of the age of the patient, timing between dose and breakthrough, and type of evidence for breakthrough, we thought it best to share their answer, so you can take the important points into account in making a decision:

From Immunize.org’s “Ask the Experts”:

A child received only one dose of varicella vaccine and subsequently tests positive for varicella IgG antibody. Does the child still need a second dose of varicella vaccine?

If a person tests positive for varicella antibody 28 days or more after vaccination, the Advisory Committee on Immunization Practices (ACIP) considers the person to be immune. CDC prefers that the child receive a second dose to assure long-term immunity, but doing so is not absolutely necessary. You can access the ACIP varicella vaccine recommendations, which include evidence of immunity (page 16) at cdc.gov/mmwr/pdf/rr/rr5604.pdf.

If Menactra was given to a healthy child at 11 years and then at 15 years, do they still need to get a third dose at 16 years of age?

Although the situation you describe is not specified in the recommendations, the reason for the second dose is that immunity begins to wane after five years. So, if a student is starting college and their last dose was given prior to age 16, they often will not be considered “up to date.” With this in mind, the patient should still receive the additional dose after turning 16 years of age.

If you had a 4-month-old infant who developed acute motor weakness (Guillain-Barre-like syndrome) within 24-48 of her routine 4-month-old vaccine series and remains hospitalized and intubated, how would you counsel her parents and the PCP regarding the future 6-month and 12-to-15-month vaccines? From reading the literature, it seems there should be no contraindication to go ahead with the regular immunization schedule as those vaccines have not shown a higher risk to develop GBS as a possible adverse event and recurrent GBS after vaccines is extremely rare. Is that how you would interpret the medical literature as well?

Diagnosis of a progressive neurologic condition or development of GBS less than 6 weeks after receipt of a tetanus-toxoid-containing vaccine is a precaution for receipt of DTaP. As such, the baby should not get DTaP until she has recovered unless an increased risk of infection with one of the diseases prevented by that vaccine is present. As you suggest, the other vaccinations can proceed if the baby is stable enough that vaccine side effects would not be confused with her health condition.

Summary and resources

We hope moving forward you, too, can benefit from the “Ask the VEC” feature of the Vaccines on the Go app. You can find this feature in the bottom bar (“Ask us”) from any page in the app or by going to the “Connect” section of the app. Find out more or download the app:

• Link to App Store
• Link to Google Play store
• About the app
• 8.5”x11” posters to hang in the office or share in patient packets — Download the PDF or order a free supply. We often address questions that parents send from the app too!