COVID-19 vaccine for children and adolescents

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The most substantial effects of the coronavirus disease 2019 (COVID-19) pandemic on children and adolescents have related more to disruptions in educational, physical, and social activities than to direct viral effects. The majority of children and adolescents with COVID-19 have mild or asymptomatic disease. Nonetheless, a small number do get severe COVID-19 disease or SARS-CoV-2-associated multisystem inflammatory syndrome in children (MIS-C), with significant direct morbidity.

Over time, genetic mutations in the SARS-CoV-2 virus have resulted in variants that are more transmissible than the original strain, referred to as variants of concern. The emergence of the Omicron variants led to significant increases in COVID-19 cases in all age groups, including children and adolescents, as well as corresponding increases in the number of hospitalizations and intensive care unit admissions. These mutations also adversely affected the level of protection offered by the original vaccines. Mutations continue to evolve.

COVID-19 vaccines have been shown to be very effective at preventing severe disease, including hospitalization and death due to COVID-19, in older children and adults. Over time, available vaccines and the recommendations for their use have and will continue to evolve in response to SARS-CoV-2 virus mutation.

Based on recommendations from the National Advisory Committee on Immunization (NACI), the recommendations below offer guidance for the vaccination of children aged 6 months and older and youth^[1]. A Canadian Paediatric Society (CPS) technical report with more details is available^[2].

Recommendations

Children and youth aged 5 years and older

• A primary series of an mRNA COVID-19 vaccine should be offered to all children and adolescents 5 years of age and older. A COVID-19 XBB.1.5 mRNA vaccine should be used. mRNA vaccines are preferred because of the availability of more data with regard to their benefits and risks compared to the Novavax vaccine^[1].
• Primary vaccination of immunocompetent children 5 years of age and over and adolescents consists of a single dose of a COVID-19 mRNA XBB.1.5 vaccine.
• Those who previously received non-XBB.1.5 vaccines should also receive a dose of an mRNA XBB.1.5 vaccine. For intervals from previous doses see Tables 1 and 2.
• With the mRNA XBB.1.5 vaccines, there is no longer a preference for Pfizer-BioNTech vaccine over Moderna vaccine for individuals 12 years of age and older because myocarditis rates are expected to be very low and similar with both vaccines. See the CPS technical report^[2], Safety and adverse events, Specific events, Myocarditis or pericarditis for details.
• The Novavax protein subunit XBB.1.5 vaccine, if available, may be offered to those 12 years of age and older who are unable or unwilling to receive an mRNA vaccine.

Children and adolescents 5 years of age and older who are moderately to severely immunocompromised should be offered a primary series of two doses of an mRNA COVID-19 XBB.1.5 vaccine, with an optimum interval of 4 to 8 weeks between doses. 

• Informed consent should include a discussion about the rare reports of myocarditis and pericarditis following COVID-19 vaccination, what warning signs to watch for (see below), and the fact that the benefits of preventing serious consequences of COVID-19 infection with vaccines far outweigh risk for myocarditis or pericarditis after the vaccine.
• Vaccination during pregnancy or breastfeeding is safe and is recommended. It provides protection for the pregnant individual, the fetus, and the infant in the first few months of life. A dose of COVID-19 mRNA XBB.1.5 vaccine is recommended for those not previously vaccinated and those who have received only non-XBB.1.5 vaccine previously.

Children aged 6 months to 4 years

• NACI recommends that children 6 months to 4 years of age who are at high risk for severe illness due to COVID-19 should be vaccinated against COVID-19 and that other children in this age group may be vaccinated. A COVID-19 XBB.1.5 mRNA vaccine should be used. The CPS suggests that the option of vaccinating children in this age group who are not at high risk should be discussed with parents.
• Children at high risk for severe illness include those who are medically fragile or who have medical complexities, more than one comorbidity, neurological disorders, chronic lung disease, trisomy 21, or immunocompromising conditions^[3].
• Considerations for COVID-19 vaccination of children in this age group who are not at high risk include local epidemiology (current high or increasing rate of COVID-19 or local outbreak), risk of exposure (day care or school attendance, other communal indoor activities), and whether the child will be in close contact with an individual at high risk of severe COVID-19.
• For immunocompetent children, the primary series consists of two doses of Moderna or three doses of Pfizer-BioNTech COVID-19 XBB.1.5 vaccine, with optimal intervals of at least 8 weeks between doses. If a child receives doses of both Moderna and Pfizer vaccines, three doses are required.
• Children who previously received non-XBB.1.5 vaccines should also receive a dose or doses of a XBB.1.5 vaccine. See Table 1 for details.
• For children who are moderately to severely immunocompromised, the primary series includes an additional dose of vaccine (i.e., three doses of the Moderna vaccine or four doses of the Pfizer-BioNTech vaccine), with optimal intervals of 4 to 8 weeks between doses. Because of fewer doses, the Moderna vaccine is recommended for this group as it may be more acceptable and more feasible to implement.

All ages

• Children and adolescents with a history of confirmed SARS-CoV-2 infection should be offered a primary series or additional doses, as indicated by age or an underlying condition. See “Previous SARS-CoV-2 infection” in the CPS document “COVID-19 vaccine for children and adolescents: Technical report”^[2] for suggested intervals between infection and vaccination.
• For the fall of 2023, NACI recommends that those previously vaccinated with non-XBB.1.5 COVID-19 vaccines receive a dose or doses of an XBB.1.5 mRNA vaccine if it has been at least 6 months from the previous COVID-19 vaccine dose or known SARS-CoV-2 infection. Shorter intervals of at least 3 months are safe, but antibody response is higher with longer intervals. This fall 2023 dose(s) is particularly important for individuals at increased risk of COVID-19 infection or severe disease. See Tables 1 and 2 for dosing information^[3].
• At present, additional vaccine doses are not required by individuals who have received doses of an XBB.1.5 mRNA vaccine as described above and in Tables 1 and 2. Additional doses may be indicated in the future because of evolving SARS-CoV-2 epidemiology or information on waning immunity after XBB.1.5 vaccines.
• For children with a previous history of MIS-C, vaccination or revaccination should be postponed until clinical recovery is complete or ≥90 days post-diagnosis, whichever is longer.
• COVID-19 vaccines may be given simultaneously with, or at any time before or after, any other vaccine(s) for children and adolescents of any age.
• Prophylactic oral analgesics or antipyretics, such as acetaminophen or ibuprofen, should not be routinely used before or at the time of vaccination, but may be considered to manage pain or fever after vaccination. Families may also be introduced to the CARD system^[4] for help in coping with fear and anxiety around injections.
• Parents should be advised to seek immediate medical attention if children or adolescents develop acute chest pain, shortness of breath, or palpitations or fainting, especially within 6 weeks following receipt of the COVID-19 vaccine.
• Paediatricians and other health professionals caring for children and adolescents should be prepared to address the concerns and fears of parents, adolescents, and children regarding the COVID-19 vaccine, including concerns about the rare reports of myocarditis/pericarditis post-COVID-19 vaccination, what warning signs to watch for, and the fact that the benefits of preventing serious consequences of COVID-19 infection with vaccines far outweigh risk for myocarditis or pericarditis after the vaccine.
• Paediatricians and other health professionals caring for children and adolescents should consider the diagnosis of myocarditis or pericarditis in children and adolescents with acute chest pain, shortness of breath, or palpitations, and ask about prior COVID-19 vaccination when these symptoms are encountered. For initial management, refer to the CPS document Clinical guidance for youth with myocarditis and pericarditis following mRNA COVID-19 vaccination^[5]. All cases of confirmed myocarditis and pericarditis post-COVID-19 vaccination should be reported promptly to local public health authorities. 
• A further dose of an mRNA COVID-19 vaccine should be deferred in children and adolescents with confirmed myocarditis, or with pericarditis if cardiac investigations are abnormal, following a previous dose, until more information about risk of recurrent myocarditis/pericarditis becomes available.
• Children and adolescents with a history of myocarditis unrelated to COVID-19 vaccination MAY receive the vaccine if the myocarditis diagnosis is remote and if they are no longer followed clinically for cardiac issues. If still being followed, expert opinion regarding vaccination should be sought.
• For individuals with a history of anaphylaxis after receiving an mRNA COVID-19 vaccine, consultation with an allergist, other appropriate physician, or special immunization clinic should be sought prior to re-vaccination. If assessment indicates that benefits outweigh potential risks, re-vaccination may be offered in a controlled setting with an observation time of at least 30 minutes following vaccination.
• Paediatricians and other health professionals caring for children and adolescents should advocate for and promote appropriate COVID-19 vaccination for children and adolescents in their jurisdictions.
• COVID-19 vaccination program planning and implementation should ensure equitable access to information and services, and minimize inequities in vaccine availability, acceptance, and uptake based on socioeconomic status or belonging to racialized or marginalized populations.
• In addition to vaccination, it is important that everyone, regardless of vaccination status, continues to follow recommended public health measures.
• For children less than 6 months of age and therefore too young to receive a COVID-19 vaccine at this time, vaccination of all eligible household members, caregivers, teachers, and other close contacts should be encouraged.

For further information including burden of COVID-19 illness in children, chronic medical conditions that may predispose to more severe COVID-19 illness, COVID-19 vaccine effectiveness, doses for primary series and boosters, vaccine adverse effects, vaccination after previous SARS-Cov-2 infection, vaccination of immunocompromised individuals or during pregnancy or breastfeeding, and contraindications and precautions, see the CPS document “COVID-19 vaccine for children and adolescents: Technical report”^[2]. 

Table 1 shows COVID-19 XBB.1.5 vaccine doses and schedules for individuals who are not moderately or severely immunocompromised, and Table 2 shows this information for individuals who are moderately or severely immunocompromised^[2][3][6]

* _{If both Pfizer-BioNTech and Moderna vaccines are used in a primary series for an individual 6 months to 4 years of age, the total number of doses in the series should follow the Pfizer-BioNTech schedule.}

† _{Shorter intervals (3 months to less than 6 months) have not been shown to pose a safety risk, but antibody response is higher with longer intervals.}

‡ _{Novavax Nuvaxovid XBB.1.5 vaccine was authorized for use in Canada on December 5, 2023. NACI guidance is pending^[6].}

* _{For doses, see Table 1.}

† _{Novavax Nuvaxovid XBB.1.5 vaccine was authorized for use in Canada on December 5, 2023. NACI guidance is pending^[6].}

‡ _{Shorter intervals (3 to 6 months) have not been shown to pose a safety risk and may be considered if necessary.}

§ _{Moderately to severely immunocompromised children who started their primary series with 2 or 3 doses of a non-XBB.1.5 Pfizer-BioNTech product when they were younger than 5 years old and are completing their primary series at 5 years of age or older should  receive a total of 4 doses of COVID-19 vaccine in their primary series (i.e., an additional dose of XBB.1.5-containing vaccine above what is listed here) at 4 to 8 weeks from the previous dose.}

CANADIAN PAEDIATRIC SOCIETY, INFECTIOUS DISEASES AND IMMUNIZATION COMMITTEE (August 2023)

Members: Michelle Barton-Forbes MD (Chair); Ari Bitnun MD; Sergio Fanella MD; Justin Penner MD; Jeannette Comeau MD, MSC, FRCPC, FAAP; Laura Sauve MD (Past chair); Raphael Sharon MD (Board representative)

Liaisons: Ari Bitnun MD, Canadian Pediatric and Perinatal HIV/AIDS Research Group; Cora Constantinescu MD, AMMI-Canada Pediatric Committee; Dorothy L. Moore MD, National Advisory Committee on Immunization (NACI); Sean O'Leary MD, Committee on Infectious Diseases, American Academy of Pediatrics; Rupeena Purewal MD, IMPACT (Immunization Monitoring Program, ACTive); Marina Salvadori MD, Public Health Agency of Canada; Isabelle Viel-Thériault MD, Committee to Advise on Tropical Medicine and Travel (CATMAT), Public Health Agency of Canada.

Principal author: Dorothy L. Moore MD

References

Disclaimer: The recommendations in this position statement do not indicate an exclusive course of treatment or procedure to be followed. Variations, taking into account individual circumstances, may be appropriate. Internet addresses are current at time of publication.