Experience and research show that most young children aren’t at risk of serious illness from Covid-19 — so should we be vaccinating them?

Children under 12 are not yet eligible for the Pfizer Covid-19 vaccine here or in many other countries — but that may soon change. The Government has announced it is preparing to make kid-sized doses of the vaccine available to children aged 5 to 11 before the end of January.

Medsafe, New Zealand’s medicines regulator, granted the vaccine provisional approval for use in children aged 12 to 15 in June. Vaccinations for this age group began in August.

Since October, the Ministry of Health has been in discussion with Pfizer about broadening its use to younger children.

Data on its use in young children from the United States has been provided to officials here since it was granted emergency approval for children aged 5 to 11 by the US Food and Drug Administration.

Ongoing research shows that the vast majority of children experience Covid-19 as a mild illness. A recent Australian study found only two per cent of children in NSW needed hospital-level care and many of those admissions were not for Covid alone. A pre-print study from Uruguay found children aged 0 to 9 have almost no chance of dying from the disease — though the risk is not zero.

So if the virus isn’t a big health risk for most children, why vaccinate them?

Although the risk of serious illness is low, the Delta variant is proving more transmissible among children and young people (just as it is in the adult population). That same Australian study found transmission was five times higher with the Delta variant than previous strains of the virus.

It’s partly a numbers game. Higher transmission leads to more cases, and more severe cases, including in children — with those who have pre-existing health conditions at greater risk.

The current outbreak in New Zealand has included cases at primary schools, high schools and universities. As of December 1, 1680 of the cases identified in this outbreak (20 per cent) are in children aged 0 to 9 years old. Another 1455 are in those aged between 10 and 19 (17 per cent).

The New South Wales study found that children were more likely to get Covid-19 from an adult than vice versa, but once they did get infected, were highly likely to pass it on to their entire household.

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So, although children themselves may not get seriously ill from Covid, they can have a hand in the spread of the virus. Real-world data and modelling suggests that the Delta variant may have put herd immunity out of reach — but vaccinating as many people as possible does still slow the spread. That helps to protect everyone, including children's parents, grandparents, and other caregivers and relatives. Extending vaccination to the 460,000 primary school-aged kids in New Zealand would expand the eligible population to about 95 per cent of the total population.

What does data say about the safety and effectiveness of the Pfizer vaccine in that age group? Clinical trial data showed a robust antibody response and good safety among 2268 children aged 5 to 11. 

The antibodies the vaccine generated in these young trial participants were similar to the levels that have proven to be protective in older age groups. Pfizer has already reported 100 percent efficacy among children and teenagers aged 12 to 15 years.

The trial found some of the children suffered mild side effects similar to those in older age groups, such as a sore arm. The study is ongoing but, because it only involves a few thousand people, has yet to detect any extremely rare side effects such as myocarditis (inflammation of the heart muscle), which is estimated to occur in about 60 boys aged 12 to 17 for every million second doses (the frequency is eight in a million for girls aged 12 to 17).

There’s no guarantee that the vaccine will be approved for 5 to 11-year-olds here but if it is, the move has already been made easier for parents. In September, the Covid-19 Technical Advisory Group (CV-TAG), which advises the government, recommended that most routine vaccinations such as MMR, HPV and the influenza vaccine can be given before, after, or at the same time as the Pfizer Covid-19 vaccine. The only exception to this is the shingles vaccine, which has a recommended seven-day gap.

Medsafe NZ group Manager Chris James says if or when Pfizer does submit an application, Medsafe will prioritise the assessment of the data for the 5 to 11-year-old age group.

If Medsafe provisionally approves the Pfizer vaccine for that age group, the technical advisory group will provide further clinical and scientific advice before it goes to Cabinet for a final ‘decision to use’.