COVID-19

Key facts

  • COVID-19 is an infectious disease that spreads easily from person to person. In some cases, it can cause severe illness, hospitalisation and death.

  • Some people have ongoing symptoms or health problems after having a COVID-19 infection.

  • Adolescents who have a very weak immune system (severely immunocompromised) or who have certain health or medical risk conditions are recommended to get a vaccine that protects against COVID-19 disease.

Last updated on 13 August 2025.

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When to vaccinate against COVID-19

It is recommended that adolescents with certain health or medical risk conditions for COVID-19 receive 2 primary COVID-19 vaccination doses. 

If you want to know if your adolescent’s health or medical risk condition puts them at risk for COVID-19, make an appointment with your nurse, doctor, or preferred health worker so you can ask them. 

Learn more about vaccinations for adolescents with medical risk conditions


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What is COVID-19?

COVID-19 is a viral infection caused by the SARS-CoV-2 virus. It spreads easily and is passed between people through sneezing, coughing, speaking, singing or breathing, and when people touch contaminated surfaces or objects.1

The most common symptoms are a sore throat, cough, runny nose, headache and fever. In severe cases, COVID-19 can cause hospitalisation and death, including in children and adolescents.2 Most children and adolescents recover quickly, but a small proportion will experience ongoing symptoms or health impacts.3

What will happen to my adolescent if they catch COVID-19?

Usual symptoms

  • COVID-19 most often causes a runny nose, headache, sore throat, sneezing, persistent cough and hoarse voice.4
  • Some people with COVID-19 infection get a loss of smell or taste (anosmia).4
     

Rare symptoms

  • Some people with COVID-19 experience severe illness, which may cause heart, brain, immune system (immunological) or breathing (respiratory) problems. Severe illness that leads to hospitalisation or death is not common in young people, but those living with a disability or medical condition may be at greater risk.5,6
  • Some people with COVID-19 can experience long COVID (post-COVID-19 condition), which is when symptoms that develop during or after COVID-19 infection continue for more than three months.3,7,8 These symptoms can include physical symptoms tiredness (fatigue), difficulty breathing (shortness of breath), chest pain and cough, memory and concentration issues, as well as psychological symptoms like anxiety, depression and post-traumatic stress disorder.7,8
  • Long COVID appears to be less common in children and adolescents than in adults, but ongoing research is monitoring this.9,10

If your adolescent is tested with a COVID-19 molecular test (not a rapid antigen test) and diagnosed with COVID-19, your local state or territory Public Health Unit may be notified.

What vaccine will protect my adolescent against COVID-19?

In Australia, unvaccinated adolescents aged 12–17 years who have a very weak immune system or a medical risk condition for COVID-19 are recommended to receive a Pfizer (Comirnaty) vaccine that strengthens immunity to COVID-19.

When should my adolescent be vaccinated?

It is recommended that adolescents under 18 years of age receive two COVID-19 vaccination doses if they:

  • have not been vaccinated for COVID-19 before; and
  • have a very weak immune system (severely immunocompromised).

Some adolescents who have a medical condition that increases their risk of severe COVID-19 can also be vaccinated for COVID-19. Make an appointment with your nurse, your doctor or your preferred health worker to see if your adolescent needs a COVID-19 vaccine course.

Adolescents with certain medical conditions may need a third COVID-19 vaccine dose.

How do COVID-19 vaccines work?

The vaccine works by ‘training’ your adolescent’s immune system to recognise and get rid of the COVID-19 virus. 

The COVID-19 vaccine recommended for adolescents contains antigens, which are tiny, harmless fragments of a COVID-19 molecule. This small COVID-19 fragment is a molecule of messenger ribonucleic acid (mRNA). This molecule ‘instructs’ your adolescent’s body to make part of a COVID-19 protein (a spike protein). Once this COVID-19 spike protein is made, it triggers your adolescent’s body to make an immune response. This trains your adolescent’s immune system to respond and protect them from the real COVID-19 virus if it enters their body.

How effective are COVID-19 vaccines?

Research shows that adolescents (aged 12–17 years) who have two primary doses of a COVID-19 vaccine will have high protection (up to 80%) against the COVID-19 virus.11

Will my adolescent catch COVID-19 from the vaccine?

No, there is no risk that your adolescent will catch COVID-19, because the vaccine does not contain the live virus that causes the disease.

What are the common reactions to the vaccine?
  • The most common reaction among adolescents aged 12–17 years who received a dose of a COVID-19 vaccine (Pfizer-BioNTech) is mild discomfort or pain where the injection was given. This pain starts to go away within a day or two after being vaccinated.11
  • After receiving a second dose of a COVID-19 vaccine (Pfizer-BioNTech), up to 65.8% of adolescents reported some common reactions in their body. This included a headache (46.1%), tiredness or lack of energy (malaise, 47.3%), joint pain (35.0%) and high temperature (fever, 22.2%).11
Are there any rare and/or serious side effects to the vaccine?
  • Very rarely (0.001–0.002% of doses, or 1–2 in every 100,000), people receiving a vaccine that protects against COVID-19 can experience a swelling or inflammation of the heart muscle (myocarditis) or the lining of the heart (pericarditis).12
  • Very rarely (0.0005% of doses given, or up to 5 episodes per 1,000,000 doses given), a dose of COVID-19 vaccine (Comirnaty Original) can cause an allergic reaction in people that affects their whole body, called anaphylaxis.13 This reaction usually happens within 15 minutes of getting the vaccine and can be treated with an injection of adrenaline. People who have this reaction usually recover quickly and don’t experience any long-term effects.14

If your adolescent doesn’t seem to be getting better or you are worried about them, you can get help: 

  • from your doctor
  • at your nearest emergency department
  • by calling Healthdirect on 1800 022 222.
What if I have more questions?

You can read some answers to common questions here.

If you still have some questions about vaccinations for your adolescent, write them down and make an appointment with your nurse, your doctor or your health worker so you can ask them.

Please note: In SKAI Adolescent, the phrase ‘your adolescent’ refers to all guardian relationships where health decisions for an adolescent fall under your responsibility.

Drafts of this page were reviewed by members of our Consumer Advisory Group.


  1. World Health Organization. Coronavirus disease (COVID-19): How is it transmitted? December 2021. Available from https://www.who.int/news-room/questions-and-answers/item/coronavirus-disease-covid-19-how-is-it-transmitted
  2. Australian Government Department of Health. COVID-19 Australia: Epidemiology Report 79. Communicable Diseases Intelligence 2023;47
  3. World Health Organization (WHO). A clinical case definition for post COVID-19 condition in children and adolescents by expert consensus. Geneva; WHO: 2023. Available from https://iris.who.int/bitstream/handle/10665/366126/WHO-2019-nCoV-Post-COVID-19-condition-CA-Clinical-case-definition-2023.1-eng.pdf?sequence=1
  4. Menni C, Valdes AM, Polidori L et al. Symptom prevalence, duration, and risk of hospital admission in individuals infected with SARS-CoV-2 during periods of omicron and delta variant dominance: a prospective observational study from the ZOE COVID Study. The Lancet 2022;399:1618-24
  5. Williamson EJ, McDonald HI, Bhaskaran K et al. Risks of covid-19 hospital admission and death for people with learning disability: population based cohort study using the OpenSAFELY platform. BMJ 2021;374
  6. Australian Government Department of Health and Aged Care. Information for people with disability about COVID-19 vaccines. May 2024. Available from 
    https://www.health.gov.au/our-work/covid-19-vaccines/disability-sector/people-with-disability
  7. World Health Organization (WHO). A clinical case definition of post COVID-19 condition by a Delphi consensus. Geneva; WHO: 2021. Available from 
    https://www.health.gov.au/our-work/covid-19-vaccines/disability-sector/people-with-disability
  8. Antonelli M, Pujol JC, Spector TD et al. Risk of long COVID associated with delta versus omicron variants of SARS-CoV-2. The Lancet 2022;399:2263-64
  9. Berg SK, Palm P, Nygaard U et al. Long COVID symptoms in SARS-CoV-2-positive children aged 0–14 years and matched controls in Denmark (LongCOVIDKidsDK): a national, cross-sectional study. The Lancet Child & Adolescent Health 20226:614-23
  10. Lopez-Leon S, Wegman-Ostrosky T, Ayuzo del Valle NC et al. Long-COVID in children and adolescents: a systematic review and meta-analyses. Scientific Reports 202212:9950
  11. Katoto PD, Tamuzi JL, Brand AS et al. Effectiveness of COVID-19 Pfizer-BioNTech (BNT162b2) mRNA vaccination in adolescents aged 12–17 years: a systematic review and meta-analysis. Human Vaccines & Immunotherapeutics 202319:2214495
  12. Hause AM, Baggs J, Marquez P et al. Safety monitoring of COVID-19 vaccine booster doses among persons aged 12–17 years – United States, December 9, 2021–February 20, 2022. Morbidity and Mortality Weekly Report 202271:347
  13. Australian Government Department of Health and Aged Care. Therapeutic Goods Administration. COVID-19 vaccine report – 02-11-23. November 2023. Available from https://www.tga.gov.au/news/covid-19-vaccine-safety-reports/covid-19-vaccine-safety-report-02-11-23
  14. Maltezou HC, Anastassopoulou C, Hatziantoniou S et al. Anaphylaxis rates associated with COVID-19 vaccines are comparable to those of other vaccines. Vaccine 2022;40:183-86
  15. McNeil MM, Weintraub ES, Duffy J et al. Risk of anaphylaxis after vaccination in children and adults. Journal of Allergy and Clinical Immunology 2016;137: 868-78