It is great to see clinical trial data supporting the safety of Pfizer’s COVID vaccine in children aged 12-16 years.

However, adults are more likely to suffer severe complications, hospitalisations and death, so our priority here in Australia and around the world is to have high coverage in adults, especially the vulnerable age groups and those who are immunocompromised or have chronic medical conditions.

Children with chronic medical conditions are an important group for consideration as a priority as supply increases in Australia

The TGA approval of the Pfizer COVID-19 vaccine in children down to the age of 12 is welcomed, reflects published evidence, and is in line with approvals and use in similar settings overseas.

Availability remains constrained, and given that COVID-19 is mild in the great majority of children, it need not be prioritised in this age range at a population level at the moment.

We should await the further ATAGI advice with respect to Pfizer COVID-19 vaccine use in [younger] children.  There are, however, a small number of children at increased risk of severe COVID-19 for whom the vaccine could be of particular benefit, and this needs to be considered.

A recent study on over 2,000 12–15-year-olds (see here) found that the Pfizer vaccine had a favourable safety profile. Most participants in the study had only mild side effects, such as pain at the site of injection or a headache.

No vaccine-related serious adverse events were reported.

Although this is a relatively small study, the efficacy of the Pfizer vaccine in this age group was 100 per cent, meaning no cases of COVID-19 were detected in those participants that received two injections of the Pfizer vaccine 21-days apart. Interestingly, 12-to-15-year-old participants produced a greater immune response to the vaccine than 16-to-25-year-olds.

Vaccinating large numbers of adults will allow us to prevent deaths and serious illness, and therefore reduce the burden on health systems. That’s the primary goal.

If we move to using the vaccine in younger adolescents then it makes sense to target higher-risk adolescents first.

The rare side effect of myocarditis/pericarditis will be monitored by our safety surveillance systems and guidelines for management are in development.

Some countries, e.g. Israel, are wondering whether a single dose is sufficient for protection, especially as most cases of myocarditis are after dose 2.

The US has been routinely giving two doses to 12-15-year-olds.

Ultimately the vaccine will move to a younger age group less than 12 years, but may be targeted to higher medically at-risk populations initially, as was done for other vaccines, e.g. meningococcal B.

Data from US safety trials of Pfizer in this age group show that it is safe and effective. This vaccine is routinely being given to all teenagers over 12 years old in the US and Canada so millions of teenagers have already received the vaccine. The close monitoring that follows after roll out of a vaccine in a population has detected a rare side effect in which the heart muscle (myocarditis) or lining (pericarditis) can become inflamed. It mostly occurs in young men and teenage boys within one week after the second dose. While more common than the TTS side effect seen with AstraZeneca, it is still rare and far less severe. No serious ongoing problems have been detected. Doctors will be on alert for symptoms in children (and young adults) who have received Pfizer, particularly after the second dose. Symptoms include chest pain and shortness of breath.

At MCRI we showed early in the pandemic – when the original viral strain was circulating - that children were less likely to be infected, less likely to experience severe symptoms, hospitalisation or death, and were less likely to transmit the infection to others. The delta strain however is more infectious for all age groups, including children and younger teens, so it is important that teens with underlying conditions that make them at higher risk of severe COVID-19 outcomes are prioritised in phase 1b immediately. For otherwise healthy teenagers, once the more vulnerable populations such as the elderly and those with co-morbidities [previously existing other illnesses] are vaccinated, it is appropriate to begin vaccinating children. Pfizer is highly effective against severe disease and death for the Delta variant. Moderna is also under consideration by the TGA for use in younger teenagers.

Safety trials in young children, infants and pregnant women are ongoing. If the data shows the vaccine is safe and effective in these age groups and populations, the vaccine rollout could be extended to these groups too. Ongoing surveillance from studies overseas in these younger age groups will also help guide us in this decision making.

In my opinion, it is not 'morally right' to prioritise children for the current COVID-19 vaccine when thousands are dying in many countries without even getting a single shot of the vaccine. For example, recently Nepal suspended its vaccination programme because of lack of vaccine supply, despite a massive surge in cases. Only 2.5 per cent of its population have been fully vaccinated so far.

Vaccine supply is too scarce at the moment. Children and adolescents tend to have milder disease compared to adults, so unless they are part of a group at higher risk of severe COVID-19, it is less urgent to vaccinate them than older people, those with chronic health conditions and health workers.

The World Health Organisation says wealthy countries should postpone their plans to immunise children and donate them to the rest of the world.