FAQs 6 months - 4 years

The following questions and answers have been developed by the National Immunisation Office.

Which COVID-19 vaccine is recommended for children aged 6 months to 4 years?

Comirnaty® KP.2 3 micrograms (0.3ml). This vaccine needs to be diluted.

Gently mix by inverting vials 10 times prior to use. Do not shake. Each dose must contain 0.3 ml of vaccine. If the amount of vaccine remaining in the vial cannot provide a full dose of 0.3 ml, discard the vial and any excess volume. Do not pool excess vaccine from multiple vials. Once the multidose vial, with a yellow cap, is punctured the vaccine should be kept at +2°C to +30°C and used as soon as possible and within 12 hours.

Spikevax 25 micrograms (0.25ml) has been licensed in other countries for children aged 6 months to 5 years but it is not being marketed in Ireland.

Which children aged 6 months to 4 years aged are recommended a COVID-19 vaccine primary course?

Those with immunocompromise associated with a suboptimal response to vaccination.
Those with medical conditions associated with a higher risk of COVID-19 hospitalisation, severe disease or death. Medical conditions associated with a higher risk of COVID-19 hospitalisation, severe disease or death are outlined in Table 5a.3).

For those aged 6 months – 4 years who are healthy, a dose of a COVID-19 vaccine primary course is not routinely recommended. However, access to the primary schedule should be available for those in this age group who, following discussion with a health care provider (e.g., GP, or pharmacist or HSE vaccinator), if parents or guardians request vaccination.

Is a booster dose recommended for children aged 6 months – 4 years?

In 2025 a Spring COVID-19 vaccine booster dose is recommended for those aged 6 months -4 years for one group only:

with immunocompromise associated with a suboptimal response to vaccination

Can other children have the COVID-19 booster vaccine if parents request it?

For those aged 6 months -4 years who are healthy, a Spring booster dose of a COVID-19 vaccine is not recommended.

What is the dose of Comirnaty® KP.2 for children aged 6 months to 4 years?

The dose of Comirnaty® for children aged 6 months to 4 years is 3 micrograms (0.3ml).

The primary course for immunocompetent children in this age group is two doses for those with no prior history of SARS-CoV-2 infection. A four-week interval is recommended between dose one and dose two. In exceptional circumstances a 3- week interval may be used. A single dose is recommended for those with a prior history of *SARS-CoV-2 infection.
For children who are immunocompromised a second dose is recommended four weeks after the first dose and a third dose may be given on advice from a relevant specialist physician and this should be given eight weeks after the second dose. A minimum interval of four weeks between the second and third dose may be used if there is urgency to achieve protection.

*A prior history of COVID-19 infection can be confirmed by either a positive PCR, a positive antigen test or by clinical diagnosis.

What should I do if the interval between doses is shorter than recommended?

If the second dose is given more than four days before the minimum interval to a child aged 6 months to 4 years with no prior history of COVID-19 infection, this is not considered a valid dose. A further dose should be given at least 8 weeks after the invalid dose. An 8 week interval is also recommended if the second dose is given more than four days before the minimum interval if the child is immunocompromised.

Where should the COVID-19 vaccine be injected?

The vaccine must be delivered intramuscularly (IM injection). For infants aged 6 months to 11 months, the recommended injection site is the anterolateral aspect of the thigh. For children aged 1 year to 4 years of age, either the deltoid muscle or the anterolateral aspect of the thigh can be used (depending on muscle mass) as the injection site.

Can other vaccines be co-administered with the COVID-19 vaccine in children aged 6 months to 4 years?

No, in this age group there must be at least a 2-week interval between the administration of the COVID-19 vaccine and any other vaccines. No interaction studies in young children have been performed on co-administration of Comirnaty® with childhood vaccines. Priority should be given to other routine childhood immunisations. Until there is more evidence it is prudent to separate COVID-19 vaccination in children aged 6 months-4 years from other vaccines for a period of 14 days.

As a precaution, if a child has recently received the mpox vaccine (Imvanex or Jynneos), they need to wait 4 weeks before they get their COVID-19 vaccine.

What are the most common adverse reactions seen in children aged 6 months to 4 years following the primary course of COVID-19 vaccination?

The most frequent adverse reactions in those that received any primary course dose included:

In infants 6-23 months of age, irritability (> 60%), drowsiness (> 40%), decreased appetite (>30%), tenderness at the injection site (> 20%), injection site redness and fever (> 10%)
In children 2-4 years of age, pain at injection site and fatigue (> 40%), injection site redness and fever (> 10%).

A higher rate of pyrexia was seen after administration of the second dose.

This medicinal product is subject to additional monitoring. This will allow quick identification of new safety information. Healthcare professionals are asked to report any suspected adverse reactions to the HPRA.

In the US, over one million children aged 6 months-5 years have received at least one dose of an mRNA vaccine (Comirnaty® or Spikevax®). The CDC reviewed adverse events and the most commonly reported symptoms were irritability or crying, sleepiness, loss of appetite and fever. Almost all (98%) reports were for non-serious events. Of the serious events reported, two were likely attributable to the vaccination, one febrile convulsion and one anaphylaxis associated with a dosing error. No cases of myocarditis were reported.

What are the contraindications and precautions with this vaccine?

Contraindications

Anaphylaxis following a previous dose of the vaccine or any of its constituents (including polyethylene glycol (PEG) and trometamol).

Appropriate support should be available in case of anaphylaxis or fainting after vaccine administration. Precautions should be in place to minimise injury from fainting.

Precautions

Acute severe illness; defer until recovery.
Previous history of myocarditis or pericarditis after any COVID-19 vaccine - seek specialist advice.
Vaccination should be postponed in children with a previous history of MIS-C, until clinical recovery or until 90 days or more since diagnosis, whichever is the longer.

What are the considerations for a child planned to begin immunosuppressing therapy?

Children with planned immunosuppressing therapy should ideally complete vaccination two weeks before treatment. The recommended minimum interval may be used. Specialists should consider the child’s risk and likelihood of disease exposure, and provide advice based on knowledge and understanding of their immune status and likely immune response to vaccination.

What are the considerations for a child who is immunocompromised?

If the child is already immunocompromised (either due to disease or treatment), they may be vaccinated if they have no contraindications. Vaccine efficacy may be lower in immunocompromised individuals.

Which Comirnaty® vaccine dose should a child receive if they are currently 4 years of age, but will turn 5 years old before they can receive a second dose?

The dose of Comirnaty® depends on the age at the time of the vaccination e.g., a 4-year-old child should receive the first dose of Comirnaty® KP.2 3 micrograms and if they have turned 5 years of age at the time of a subsequent dose, the dose given should be Comirnaty® KP.2 10 micrograms for those aged 5-11 years.

Therefore, if a child becomes five years of age before completion of the recommended course, the schedule should be completed with the age appropriate dose, Comirnaty® KP.2 10 micrograms for those aged 5-11 years.

How can I ensure that the right formulation of Comirnaty® is given to the appropriate age group?

The following checks are routinely recommended before COVID-19 vaccination:

Is this a primary course and what dose number is it?
What is the age of the person?
What is the recommended vaccine for this age-group?
What is the recommended dose?
What is the recommended interval since the last dose?
Has the person had COVID-19 infection? What is the recommended interval since laboratory-confirmed COVID-19 infection?