COVID-19 vaccination in children and adolescents

Vaccination against COVID-19 is recommended for all individuals aged 5 years and older.¹

There are three COVID-19 vaccines currently approved and available for use in Australia as part of the national rollout:

• AstraZeneca COVID-19 vaccine (Vaxzevria)
• Moderna COVID-19 vaccine Spikevax (elasomeran) – on track to arrive in September 2021
• Pfizer/BioNTech COVID-19 vaccine (Comirnaty).
• The paediatric Pfizer vaccine can be given to children aged 5 to 11 years.

The age at which a person can get a COVID-19 vaccine depends on the type of vaccine and the information that has been gathered on the safety, efficacy (how well it works in clinical trials) and effectiveness (how well it works in the real world) of that vaccine.

The recommended ages are different for each vaccine. The vaccine product information lists the ages for use that have been approved by the Therapeutic Good Administration (TGA):²

• The AstraZeneca vaccine can be given to people aged 18 years and over.
• The Moderna vaccine can be given to people aged 12 years and over.^a
• The Pfizer vaccine can be given to people aged 12 years and over.

^aTGA provisional approval for use of the Moderna COVID-19 vaccine in people aged 12–17 years was provided 4 September 2021.

Does age matter with other vaccines?

It is not unusual for age to influence the type of vaccine available. For example, there are eight different influenza vaccines approved for use in Australia this year. However only three of these can be used in children aged 3 years or under, and only five of them can be used in children aged 5 years or younger.³

For more about influenza vaccines, read our article.

Yes. Adolescents can be vaccinated against COVID-19.⁴ In Australia, the TGA recently extended provisional approval for the Pfizer vaccine on 27 August 2021, to include use in adolescents 12–15 years of age. Previously the Pfizer vaccine had been approved for people aged 16 years and over.⁵

This extension to the approved indication was made by the TGA following careful evaluation of all available safety and effectiveness data including from clinical trials that involved 12–15 year-olds.⁶ Provisional approvals from the TGA are valid for a period of 2 years.

The Australian Technical Advisory Group on Immunisation (ATAGI) recommends two doses of the Pfizer vaccine for adolescents aged 12–15 years.⁷

This follows a previous recommendation that the Pfizer vaccine initially be prioritised for adolescents aged 12–15 years with a higher risk of becoming infected, or severely ill with COVID-19. ATAGI have stated that the benefits of offering COVID-19 vaccines to all young people aged 12–15 years outweigh the known and potential risks.¹

You can read the full ATAGI statement regarding vaccination of adolescents aged 12–15 years.

What about adolescents who are 16–18 years old? 

People aged 16–18 years can be vaccinated with the Pfizer COVID-19 vaccine.

Note that state and territory government health advice may be different depending on current COVID-19 cases and outbreaks. Check with your local state or territory health department for more information.

Read more about COVID-19 vaccine eligibility.

Children who are 5 years or over can be vaccinated against COVID-19. In Australia, the TGA recently extended provisional approval for the Pfizer vaccine on 3 December 2021, to include use in children 5–11 years of age. Previously the Pfizer vaccine had been approved for people aged 12 years and over.

However, a lower dose (10 mcg) will be given to children aged 5–11 years, compared to that used for individuals 12 years and older (30 mcg).

As research continues into COVID-19 vaccines, studies are being expanded to include younger children. Various studies underway in other countries are examining COVID-19 vaccines in children aged between 6 months and 17 years.⁸ Once published, the results of these studies will provide further information about the risks and benefits of vaccinating young children against COVID-19. Research into vaccines in young children may also be conducted in Australia in the future.

Health experts, the TGA and groups like ATAGI will continue to examine emerging evidence on the safety, efficacy and effectiveness of COVID-19 vaccines in children. Approvals for vaccine use in Australians of all ages is based on the best available evidence. And with many children in other countries having received COVID-19 vaccines, real-world experience of vaccine side effects will provide additional safety information. This points to the importance of reporting side effects or adverse events that are likely caused by vaccines.

Read more about COVID-19 vaccine side effects: how to manage them and when to report them.

Data on the Pfizer vaccine (Comirnaty)

A research group in the United States investigated the safety and efficacy of the Pfizer vaccine in 2,260 adolescents (referred to as children in this study) aged 12–15 years.⁹

Half the group (1,131 children) received the two doses of the vaccine 21 days apart, while the other half (1,029 children) received two doses of placebo – a dummy injection of saline (salt water). Injections of the vaccine or the placebo were given into muscle, usually the arm. Neither the vaccine providers nor the children knew which they were going to receive.^9,10 This is called a double-blind placebo-controlled trial.

Over half of the study participants were followed up for at least two months after the second dose to see if there were any long-lasting or serious side effects.^9,10

The efficacy of the Pfizer vaccine was assessed in children from 12–15 years of age, the majority of whom who had no evidence of previous infection with COVID-19.

Among the children with no evidence of previous infection, none of those in the vaccine group developed COVID-19 compared to 16 children in the placebo group who developed COVID-19 at least 7 days after the second dose. These study results showed that the vaccine was 100% effective at preventing COVID-19 (although the true rate could be between 75% and 100%) based on scientific analysis.^4,9,10

The study also showed that the immune response to the Pfizer vaccine in children aged 12–15 was comparable to the immune response in older age groups (16–25 years). Immune response is measured by the level of antibodies that the body produces against the coronavirus that causes COVID-19 (SARS-CoV-2).

The health experts evaluating the results of the study concluded that the benefits of the Pfizer vaccine in this age group outweigh the risks, especially in children who have conditions that increase the risk of severe COVID-19 disease.^4,9,10

Read more about clinical trials and why they are important

What did they learn about side effects from the Pfizer vaccine?

The most commonly reported side effects in the 12–15-year age group were the same as those reported by adults in earlier phases of the study: pain at the injection site, tiredness, headache, chills, muscle/body aches, fever and joint pain. The side effects were usually mild to moderate and went away within a few days following vaccination.^4,9,10

Similar to the occurrence of side effects seen in adults who received the Pfizer vaccine, it appears that vaccine side effects in children are more likely to occur after the second dose.

Since the commencement of the Australian national vaccination program in February 2021, safety evaluation data has been gathered from over 1 million people who received the first dose of Pfizer and over 770,000 people who received both doses. The two most commonly reported side effects were: 

• injection site pain (30% following the first dose vs. 43% after the second dose)
• tiredness (21% after the first dose vs. 43% after the second dose).

Symptoms were generally mild and short-lived.¹¹

This information is useful for people giving and receiving the vaccination to know to expect some mild side effects after either dose, but even more so after the second dose. The safety evaluation of the Pfizer COVID-19 vaccine in 12–15 year-olds is ongoing.^4,10

Rare side effects can happen with any medicine or vaccine. Health experts have acknowledged the difficulty detecting rare side effects from the vaccine due to the limited number of children included in the Pfizer study.¹²

It should be noted that in adults under 30 years of age, very rare cases of myocarditis and pericarditis (inflammation of the tissues surrounding the heart) have been observed following vaccination with Pfizer. These cases have mostly occurred within 14 days after vaccination, more often after the second vaccination, and more often in younger men.¹³ No cases of myocarditis or pericarditis have been observed in children 12–15 years who received the Pfizer vaccine as part of the US study.⁹

Data on the Moderna vaccine (Spikevax)

There is evidence that the Moderna vaccine has efficacy against symptomatic COVID-19 in people aged 12–17 years. This data comes from ongoing clinical trials involving around 4,000 participants aged 12–17 years of age.¹⁴

Study participants were randomly assigned to receive either two doses of the Moderna vaccine (2489 participants) or placebo (1243 participants). The two doses were given 28 days apart.

Efficacy against symptoms of COVID-19 was 92.7% two weeks following the first dose of the Moderna vaccine and 93.3% following the second dose, when compared with participants who were given the placebo injections. Results were similar to those reported in people aged 18–25 years who had received the Moderna vaccine.^1,14

Were there side effects from the Moderna vaccine?

Side effects were reported after both doses but were more common after the second dose. Side effects included injection site pain, headache, fatigue, muscle aches and chills. Side effects that persisted for up to 28 days after any dose were more frequent in the vaccine group (20.5%) than the placebo group (15.9%). These included swelling at the injection site (4.3%) and headache (2.4%). No cases of myocarditis or pericarditis were reported.¹⁴

As yet, no Australian safety evaluation data has been gathered on the Moderna vaccine.

Find out more at AusVax Safety

Sometimes medicines, including vaccines, have unexpected and undesirable side effects. Any side effects should be reported. The Adverse Medicine Events Line provides a way of reporting and discussing adverse experiences with medicines.

Find out more about reporting side effects on the Adverse Medicines Events Line

Data on the Pfizer vaccine (Comirnaty)

A research group in the United States investigated the safety and efficacy of the Pfizer vaccine in 2268 children aged 5–11 years.

Two-thirds of the group (1518 children) received two doses of the vaccine 21 days apart, while the other third (750 children) received two doses of placebo.

95% of the study participants were followed up for at least 2 months after the second dose to see if there were any long-lasting or serious side effects.

Among the children with no evidence of previous infection, three in the vaccine group developed COVID-19 compared to 16 children in the placebo group who developed COVID-19 at least 7 days after the second dose. The study results showed that the vaccine was 90.7% effective at preventing COVID-19 (although the true rate could be between 67.7% and 98.3%) based on scientific analysis.

The study also showed that the immune response to the Pfizer vaccine in children aged 5–11 years was comparable to the immune response in older age groups (16–25 years).

The health experts evaluating the results of the study concluded that the safety, efficacy and immune response data support vaccination of children aged 5–11 years with two 10 mcg doses of the Pfizer vaccine.

What did they learn about side effects from the Pfizer vaccine?

The most commonly reported side effects in the 5–11-year age group: pain at the injection site, tiredness, headache, chills and muscle pain. The side effects were usually mild to moderate, lasting 1 to 2 days. It appears that vaccine side effects are more likely to occur after the second dose. No vaccine-related serious adverse events were noted.

In many ways, vaccine studies involving children are similar to those conducted in adults. The vaccine study including the methods and risks are discussed with the caregiver or legal guardians, and with those children who are old enough to understand. Consent forms are signed once the guardian and/or child are adequately informed and agree to participate.

When studying vaccines in children under 12 years of age, the first group to receive the vaccine would normally be on the older end of the spectrum. The participants receive a range of doses to find one that triggers a strong immune response without too many side effects.

Once an ideal dose is identified, several thousand participants are usually randomised to receive either the vaccine or a placebo injection. Researchers then follow the children for months and even years, to study the safety and effectiveness of the vaccines.

At the beginning of the pandemic, it was apparent that children were more likely to develop milder symptoms compared to adults when infected with COVID-19.^15,16 As the first vaccines became available to protect against COVID-19, the focus was on getting adults vaccinated as quickly as possible.

New strains (or variants) of the virus continue to emerge – such as the delta strain which has been named a ‘variant of concern’ as it is more transmissible than the earlier forms of the virus.¹⁷

With this increased risk of people passing on the virus, the focus has shifted to vaccinating young people against COVID-19 and more researchers are now studying COVID-19 vaccines in children.⁸

Unless children are part of a group who have complex medical conditions or higher risk of developing severe COVID-19, there is less urgency to vaccinate children than there is to vaccinate other groups including people with chronic health conditions, health workers and other frontline workers.¹⁸

More evidence is needed on the use of the different COVID-19 vaccines in children to be able to make general recommendations on vaccinating children against COVID-19.¹⁸

It is important for children to continue to have the recommended childhood vaccines, including the flu vaccine.

Find out more about the National Immunisation Program

Read about Influenza vaccines and COVID-19

COVID-19 can cause serious illness in children. With new strains emerging, we are seeing more children become unwell and vaccination is one of the best ways to protect them.

Some experts recommend that all children be vaccinated against COVID-19 because they may be able to spread COVID-19 through family groups and schools. Some people with COVID-19 can exhibit mild symptoms such as a sore throat, or they may have no symptoms at all. There is some evidence that even people who are asymptomatic can still transmit the virus and we have seen evidence, especially overseas, of asymptomatic spread.¹⁹

Evidence is also building that vaccines could block transmission of the virus that causes COVID-19 (SARS-CoV-2), so vaccinating children as well as adults can help reduce rates of transmission among the wider community.²⁰

How many Australian children have been diagnosed with COVID-19?

To date, there have been 33,043 cases of COVID-19 in Australian children aged from 0–9 years and 33,321 cases in Australians aged 10–19 years. Three deaths have been reported in these age groups.²¹

Are there serious effects from COVID-19 in children?

Like adults, children can become seriously unwell with COVID-19, though it appears the risk of serious illness and death is lower compared to adults. The risk of serious illness may also depend on the strain of COVID-19, with earlier strains eg, alpha, being less problematic in children.

In rare circumstance, children who have experienced even mild symptoms from COVID-19 can later develop a condition called multi-system inflammatory syndrome in children.^16,22

Multi-system inflammatory syndrome in children (MIS-C) is a condition where different organs in the body become inflamed, including the heart, lungs, kidneys, brain, skin, eyes, or gastrointestinal organs. Not much is known about the causes of MIS-C. However, we do know there have been cases of MIS-C in children who have either been infected with COVID-19 or had been around someone with COVID-19.²²

MIS-C can be serious, and deaths have occurred in rare cases, but most children diagnosed with this condition recover with medical care.

You can read more about MIS-C in this article.

As new and faster-spreading strains of the virus emerge and more adults are vaccinated, there is a higher likelihood that children and adolescents could be contributing to spread of the virus.

Vaccinating children and young people will not only protect them against severe disease but could also decrease the chance of them spreading the virus to other people.²⁰

At this stage, Australian children aged 5 years and over can receive the Pfizer vaccine. Australian children who are younger than 5 years are not yet able to access a COVID-19 vaccine.¹ This is because the safety and effectiveness of COVID-19 vaccines is still being studied in children under 5 years of age.

Until there is enough evidence on the use of COVID-19 vaccines in children aged 5 years and under, the TGA and other independent health experts are unable to evaluate or make informed decisions to approve COVID-19 vaccines in this age group. But evidence on vaccines that prevent COVID-19 disease are continually emerging, so the status of vaccinations in Australian children of all ages is sure to change in the near future.

Find out more about COVID-19 vaccines information for health consumers