EXPERT REACTION: Pfizer cleared to apply for vaccine approval for under 5s

A step in the right direction.

New variants continue to emerge with the possibility of more fluctuations in COVID infections over coming months. While children at this age group’s risk of severe COVID remains low, they can still acquire and transmit the virus to others. A small percentage of children also require hospitalization after COVID and face rare but life-threatening risks such as multi-system inflammatory syndrome, or MIS-C, with some children developing longer-term, chronic COVID symptoms. Evidence suggests that offering the vaccine ahead of another potential wave will protect this very small number of children from serious illness and hospitalisation and will also provide some short-term protection against mild infection across the age group.

In this scenario, we should not only consider a specific child’s risk (in this age group) of severe disease, but also the risk of those who they are in close contact with, including family and older relatives who may have underlying conditions. What level of exposure risk children have (for example, are they in day-care or frequently participating in activities that put them in close proximity to others who may be sick in indoor settings?) What levels of COVID-19 are circulating in a specific community?

Safety?

The vaccine is safe for children ages 6 months and up. In the clinical trials for this age group, there were no reported cases of myocarditis, pericarditis and death. Pfizer- BioNTech’s three-dose Covid vaccine for children 6 months to 5 years old was 80% effective at preventing illness during the Omicron wave. The safety data for the Pfizer vaccine is based on 1,678 children under age 5 who received a third shot at least two months after the second dose when Omicron was the main variant in circulation. Pfizer examined a subset of children to determine the immune response of kids under age 5. The 80% effectiveness against Omicron is based on a preliminary analysis.

The TGA has granted provisional determination to Pfizer in regard to the use of their vaccine for children aged six months to five years of age. It’s important to appreciate that this is only the first step in the process for this vaccine to be approved for use in this age group in Australia.

What it means is that Pfizer have been given the go ahead to apply for provisional registration for the use of this vaccine in young children. When they do this, the TGA will go through all of the available information with a fine tooth comb before making a decision whether to approve the vaccine for this age group.

If this were to happen, it would then be up to ATAGI to take on board all that we know about COVID-19 in this age group and the relevant vaccine safety and effectiveness data to decide whether to recommend this vaccine for children this age group. As we’ve seen throughout the pandemic ATAGI is very thorough in reviewing the data and very cautious when it comes to recommending vaccines. Despite this, there is little reason to expect that the vaccine wouldn’t be recommended as all of the available data from clinical trials suggests that the vaccine in the doses selected for young children is very safe and effective.

The new Pfizer vaccine for children aged under five creates an immune response, but because it's a lower dose,  it requires three injections instead of two.

This provides protection but is not very convenient for parents. The issue of COVID in young children is especially focused on that small minority who has a major medical problem including immunosuppression. Should the new Pfizer vaccine be recommended in Australia it would best be focused on children at high risk of severe COVID. Other vaccines should soon be available that only require two injections.

It's also really important for parents to realise that influenza may well be more severe in young children than COVID. Vaccination against influenza in children aged under five is free and recommended and requires only one dose. Children, like adults, can have COVID and flu vaccines at the same time in separate arms. 

Winter boosters against both diseases are safe and effective. And definitely worth having.

COVID in young children can occasionally be severe even in healthy children and that is why universal vaccination for all children is offered, so as to protect the vulnerable first, but also to protect the healthy child who unusually gets severe COVID.