7 Key Changes: The 2021 Child and Adolescent Immunization Schedules

William T. Basco, Jr, MD, MS


February 17, 2021

Each February, the Centers for Disease Control and Prevention (CDC), along with multiple professional organizations, releases an updated Recommended Child and Adolescent Immunization Schedule. Recent years have seen fewer changes in the vaccine schedule, mostly with adjustments based on products coming on or off the market, and sometimes with slight changes in recommendations. This year is no different, with mostly minor changes in store. As most practitioners know, having quick access to the tables that accompany the recommendations is always handy. Table 1 contains the typical, recommended immunization schedule. Table 2 contains the catch-up provisions, and Table 3 provides guidance on vaccines for special circumstances and for children with specific medical conditions.

2021 Childhood and Adolescent Immunization Schedule

One update is a recommendation that patients with egg allergies who had symptoms more extensive than hives should receive the influenza vaccine in a medical setting where severe allergic reactions or anaphylaxis can be recognized and treated, with the exclusion of two specific preparations, Flublok and Flucelvax.

In regard to the live attenuated influenza vaccine (LAIV), there are several points of reinforcement. First, the nomenclature has generally been changed to "LAIV4" throughout the document because only quadrivalent preparations are available. There are specific recommendations that patients should not receive LAIV4 if they recently took antiviral medication for influenza, with "lockout" periods lasting from 2 days to 17 days, depending on the antiviral preparation used. In addition, there is an emphasis on not using LAIV4 for children younger than 2 years.

Two updates to the meningococcal group B vaccine are worth reviewing. The first is that children 10 years of age or older with complement deficiency, complement inhibitor use, or asplenia should receive a meningitis B booster dose beginning 1 year after completion of the primary series, with boosters thereafter every 2 or 3 years as long as that patient remains at greater risk. Another recommendation for patients 10 years or older is that even if they have received a primary series of meningitis B vaccines, they should receive a booster dose in the setting of an outbreak if it has been 1 year or more since completion of their primary series.

Recommendations have generally been relaxed for tetanus prophylaxis in older children, indicating that individuals requiring tetanus prophylaxis or their 10-year tetanus booster after receipt of at least one Tdap vaccine can receive either tetanus-diphtheria toxoid or Tdap.

COVID-19 Vaccines

Although childhood vaccination against COVID-19 is still currently limited to adolescents involved in clinical trials, pediatricians surely are getting peppered with questions from parents about whether they should be vaccinated and what to make of the recent reports about allergic reactions. Fortunately, there are several resources for pediatricians. First, two reports point out that true anaphylactic reactions to COVID-19 vaccines appear quite rare. The reported data on Pfizer-developed mRNA vaccine demonstrated an anaphylaxis rate of approximately 2 cases per 1 million doses administered. Among the 21 recipients who experienced anaphylaxis (out of over 11 million total doses administered), fully one third had a history of anaphylaxis episodes. The report also reviews vaccine reactions that were reported but were not classified as anaphylaxis, pointing out that when reporting vaccine reactions, we should be very careful in the nomenclature we use.

Reporting on the Moderna mRNA vaccine showed anaphylaxis rates of about 2.5 per 1 million doses, with 50% of the recipients who experienced true anaphylaxis having a history of anaphylaxis. Most of those who experienced anaphylaxis (90% in the Moderna group and 86% in the Pfizer group) exhibited symptoms of anaphylaxis within 30 minutes of receiving the vaccine. The take-home point, and the current CDC recommendation, is that many individuals, even those with a history of anaphylaxis, can still receive COVID-19 vaccines. The rates of observed anaphylaxis after COVID vaccination are far below population rates of a history of allergy or severe allergic reactions. When coupled with an estimated mortality rate of 0.5%-1% for SARS-CoV-2 disease, CDC recommends that we encourage people, even those with severe allergies, to get vaccinated.

One clear caveat is that individuals with a history of severe anaphylaxis, and even those concerned about allergies, should be observed for a longer period after vaccination (at least 30 minutes) than the 15 minutes recommended for the general population. In addition, individuals with a specific anaphylactic reaction or severe allergic reaction to any injectable vaccine should confer with an immunologist before considering vaccination.

Another useful resource is a column published by the American Medical Association that walks through some talking points for providers when discussing whether a patient should receive COVID-19 vaccination. Advice is offered on answering patient questions about which preparation to get, what side effects to watch for, and how to report an adverse reaction. Providers are reminded to urge patients to complete whichever series they begin (get that second dose!), and that they currently should not have to pay for a vaccine. FAQ resource pages are available for patients and healthcare providers.

More Vaccine News: HPV and Influenza

Meanwhile, published vaccine reports provide evidence from the field to demonstrate the benefits of vaccination. A study published in NEJM reported on the effectiveness of HPV vaccine in a Swedish cohort. The report evaluated females who were between 10 and 30 years old beginning in 2006 and followed them through 2017, comparing rates of invasive cervical cancer among the group who received one or more HPV vaccine doses with the group who receive none. Even without adjustment, the raw rate of invasive cervical cancer in the vaccinated group was half of that in the unvaccinated group. After full adjustment, some populations experienced incident rate ratios that were greater than 80% reduced. The largest reduction, and therefore the biggest benefit, was among those who received the HPV vaccine before age 17.

A report from the United States looking at the 2018-2019 influenza season demonstrated a vaccine effectiveness rate against hospitalization of 41% and 51% against any emergency room visit related to influenza. The authors note that there was considerable drift in the influenza A type that appeared late in the influenza season, reducing the overall effectiveness, but that the vaccine was still largely effective.

William T. Basco, Jr, MD, MS, is a professor of pediatrics at the Medical University of South Carolina and director of the Division of General Pediatrics. He is an active health services researcher and has published more than 60 manuscripts in the peer-reviewed literature.

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