Questions about vaccines

In Australia, children receive mRNA COVID-19 vaccines. An mRNA vaccine is a way to deliver a message to cells in the body.

For mRNA COVID-19 vaccines, the message delivered to cells is the instructions on how to make just one part of the COVID-19 virus – the “spike protein”. Cells then start making this spike protein. Because the message in the mRNA vaccine tells cells to make only the spike protein, and not the entire COVID-19 virus, it can’t make a person sick from COVID-19.

The immune system recognises the generated spike proteins on the cells as being new to the body and starts training itself to prepare for if it ever a full COVID-19 virus. If a vaccinated person is exposed to COVID-19, the immune system immediately recognises the COVID-19 virus’s spike protein, and generates a strong and rapid immune response to try and limit.

Whenever we consider a vaccine in any population and any disease, we need to take into consideration three important pieces of information:

• Does the disease cause problems in that age group? While complications or severe disease is uncommon in children, it does occur, so we want to be able to prevent that.
• Does the vaccine work in that age group? The data we have for children so far indicates that vaccines are working for them.
• Are the vaccines safe for that age group? Currently, the rate of complications from a COVID-19 infection in children is higher than the rate of side effects from COVID-19 vaccines in that age group. So, although the rate of hospitalisation is low, the benefit of the vaccine outweighs the risk.

It is important that we let children keep on doing what children do. We have seen the disruption that COVID-19 can have on young lives from a schooling perspective and also on the social and emotional aspects of their lives.^{28, 29} Vaccination is one of the best ways to prevent these complications.

Vaccinating is about risk-benefit for the individual, their family, as well as their community. These vaccines are likely to reduce transmission, which helps to slow the virus spreading in the community and reduce the likelihood of new strains appearing.³⁰ Also, the less people get sick, the easier it is to maintain critical services including hospitals and other healthcare services for people with and without COVID-19, and keeping schools and childcare open. Vaccination can limit this impact: recent data from NSW shows that the hospitalisation rate among unvaccinated people aged 12 years and older is 7 times higher than vaccinated people in the same age group.³¹ The ICU admission rate is also 18 times higher in unvaccinated people.³¹

In WA, children can be vaccinated in the same places adults can get vaccinated. These include:

• General Practice (GP) clinics
• State-run clinics in Perth and in regional areas
• Some pharmacies
• Aboriginal Medical Services
• Some high schools

It is up to each state and territory to decide where people can receive their COVID-19 vaccines. In WA, you can make an online booking for your child through these three websites:

• https://rollup.wa.gov.au/
• https://www.hotdoc.com.au/
• https://www.health.gov.au/resources/apps-and-tools/covid-19-vaccine-clinic-finder

Australians aged 18 years and older are recommended to receive a booster four months after their second dose, irrespective of what brand of vaccine was received for the first and second doses.

This is recommended because we see waning of protection in adults, especially the elderly. Children have incredibly robust immune systems that have a fantastic response to the vaccine. At this stage, it is not yet recommended that children receive boosters. However, it is now recommended that severely immunocompromised children aged 5 or older should receive three initial COVID-19 vaccines, in which the third dose is received 2 to 4 months after the second dose.⁷ Third doses for this cohort are not classified as boosters.

There have been rare reports of more serious side effects such as heart inflammation (myocarditis) in children and adults.

However, even with the increased risk, myocarditis is a rare occurrence (1–2 cases per 100,000 people or 8-12 cases per 100,000 people in older adolescent and young adult males)³² and we would strongly advise all children aged 5 years and older to be vaccinated. The risk of serious health consequences is far greater to those who get COVID-19, than those who get the vaccine. For example, evidence from the US shows that young males are 6 times more likely to develop myocarditis from a COVID-19 infection than from the COVID-19 vaccine.³³

For most, myocarditis and pericarditis (heart inflammation) is mild, improves with anti-inflammatory medication and have no ongoing impairment of cardiac function.³⁴ It’s important that anyone who has a sore chest, shortness of breath or a fast heartbeat 1–5 days after vaccination see their GP or an emergency department so it can be monitored and managed there. If someone who has recently been vaccinated is experiencing chest pain, it’s best to avoid any vigorous exercise and to seek medical attention. This potential side-effect can’t be prevented. There are ongoing studies occurring in the US and Canada on the long-term effects of myocarditis and pericarditis following COVID-19 vaccination.³⁴

While we have only been vaccinating against COVID-19 for 12 months, we have been vaccinating against other diseases for decades. History tells us that if side-effects are going to happen, they happen within days to weeks following vaccination.

In Australia, many people may recall receiving a text message or email after their COVID-19 vaccine asking how they were feeling – this is scientists collecting data on how the whole of Australia is feeling after their vaccines.³⁵ Each state also has their own vaccine safety program. In WA, everyone can also report side-effects through the Western Australian Vaccine Safety Surveillance (WAVSS) system. Specialised nurses and doctors look through all the reports, and then all feedback is sent to the Therapeutic Goods Administration (TGA), which is the body that approves vaccines and tracks vaccine safety in Australia. Individuals can also report side effects directly to the TGA. All side-effects are followed up closely, particularly severe ones.

Some people have raised concerns about vaccines and fertility. No vaccine we use has ever had an impact on fertility - studies have already shown us that there’s been no difference in fertility levels in women or men before and after COVID-19 vaccination.^36-40 Small, and importantly temporary, changes to the menstrual cycle have been detected in women who receive a COVID-19 vaccine, in which the time between bleeding increased by less than 1 day.⁴¹

With billions of doses of COVID-19 vaccines given globally, we know what to watch out for. We don’t expect surprises; however scientists will continue to look at rare side-effects. Based on the data so far, we are not seeing any unexpected side effects of the vaccines.

Given the importance of ensuring protection against other vaccine-preventable diseases and maintaining high vaccine uptake, vaccine experts support giving vaccination on the same day.⁴²

There is a possibility that early side effects including local reactions and fever may be increased when multiple vaccines are given together. 

As our international borders open up, the likelihood that influenza will return to Australia is incredibly high. This is because it’s now been over two years since Australians have had any real exposure to influenza. So in addition to receive a COVID-19 vaccine this year, it’s also important to receive an influenza vaccine. Anyone over the age of 6 months can receive an influenza vaccine, and it’s free for the following:

• Children between 6 months and less than 5 years
• People of any age from 6 months with an underlying health condition
• Pregnant women
• All Aboriginal and Torres Strait Islander people
• Primary school-aged children (in WA)

Otherwise, it will cost you about $15-$20. If your child is aged between 6 months and younger than 9 years, and 2022 is the first year they will receive an influenza vaccine, it’s recommended that they receive two influenza vaccine doses given 4 weeks apart. Everyone else requires just one dose.

"Hesitancy is common and it’s ok to be hesitant. A new vaccine requires thoughtful consideration by scientists and parents.

My advice to parents is to know you have an incredibly precious window. COVID-19 is coming to WA, so use this time to get yourself and your family vaccinated, if they can be.

My teenage children are vaccinated, and I encourage other parents to get their teenagers and primary-school-aged children vaccinated. Vaccination is a very important component of much broader strategies and protection. If you are unwell, follow the public health advice. And everyone should continue with regular hand washing and cough etiquette – not only for COVID but for all respiratory infections."

At this stage, it is not mandatory for children to be vaccinated in order to go to childcare or school.

Australia’s vaccine experts recommend that COVID-19 vaccination should not be mandatory for school and other activities critical to a child’s development and wellbeing.⁴³ In the event of a COVID-19 outbreak at a childcare or school, parents should follow the public health advice given at the time. It is currently advised that children attend childcare and school.

In Australia, teenagers can receive either Pfizer or Moderna COVID-19 vaccines. While they are different vaccines, they both use similar mRNA technology.

It is recommended that children aged 12+ years receive two COVID-19 vaccine doses. Those receiving the Pfizer vaccine need at least 3 weeks between doses and those receiving the Moderna vaccine need at least 4 weeks between doses.

Children aged 12 through 15 given either vaccine can experience side effects similar to those experienced by people age 16 and older.

The most common side effects include pain where the vaccine needle was given, fatigue, headache, chills, muscle pain, fever and joint pain.³⁵ Though these side effects indicate that an immune response has been triggered, there is no evidence that those who experience side effects after their COVID-19 vaccine go on to have better immunity than those who did not have any side effects.⁴⁴

See here for more specific information on myocarditis.

The data tells us that Pfizer and Moderna vaccines work similarly in teenagers.

Evidence from the US for children aged 12 – 18 years shows that two doses of the Pfizer vaccine is over 90% effective against COVID-19 hospitalisation, if the child got their second dose at least 14 days before having COVID-19 symptoms.^{45, 46}

Two doses of the Moderna vaccine is also over 90% effective at preventing COVID-19 in teenagers, at least 14 days after receiving the second dose.⁴⁷ Further evidence from the US in this age group shows that receiving two doses of the Pfizer vaccine is 91% effective at preventing MIS-C from occuring.²²

The Pfizer vaccine is currently the only COVID-19 vaccine available for 5–11-year-olds.

It is recommended that children in this age group receive two doses of the Pfizer vaccine, spaced 8 weeks apart. Other mRNA vaccines, such as Moderna, are being studied and may be available in the future. There are also clinical trials underway for children aged younger than 5 years. For example, Pfizer is currently trialling the vaccine for children aged 6 months to under 5 years and is expected to have data on the safety and efficacy of the vaccine in this age group in the first half of 2022.⁴⁸

Moderna is also trialling a vaccine for children aged 6 months to under 12 years; it is expected that this trial will finish by June 2023.⁴⁹

The United States (US) started vaccinating children aged 5–11 years in November 2021.

This was after a clinical trial with several thousand children showed that the Pfizer vaccine was safe and effective in this age group. Now, more children in this age group in the US have received their first Pfizer dose compared with the entire 5–11-year-old population in Australia. As of the 19^th of December 2021, 8.7 million doses of the Pfizer vaccine had been given to children aged 5 – 11 years in the US.⁵⁰

Australia has been watching the US very closely to see whether any rare and/or serious side effects, including myocarditis (heart inflammation), are detected in children aged 5–11 years. So far, the data provided has greatly reassured Australia’s vaccine expert committee. These experts will continue to monitor reported side effects both internationally and nationally.

Vaccines in this age group are tolerated well with similar side effects to those seen in teenagers and adults.³⁵

Fever, muscle aches and pain, fatigue, and headaches are the most common side effects.

For every vaccine, we need to make sure that the dose achieves a balance of maximum benefits (how effective it will be) for minimum risks (how safe and tolerable it will be).

This process occurs whenever we use a vaccine in new age groups. Based on clinical trials, scientists found that the balance is achieved for children aged 5–11 years when they receive a third of the dose that people aged 12 years or older receive.  The dosage is based on age, not weight.⁴³

COVID-19 vaccines are most effective against severe forms of COVID-19.

Based on published studies, the Pfizer vaccine is working as well in 5–11-year olds as older children and adults, preventing more than 90% of infections 7 days or more after the second dose in children aged 5–11 years.⁵¹ These vaccines are highly effective against preventing infection and severe outcomes that require hospitalisation.

1. Molteni E, Sudre CH, Canas LS, et al. Illness duration and symptom profile in symptomatic UK school-aged children tested for SARS-CoV-2. The Lancet Child & Adolescent Health. 2021;5(10):708-718.
2. Williams P, Koirala A, Saravanos G, et al. COVID-19 in children in NSW, Australia, during the 2021 Delta outbreak: severity and disease spectrum. medRxiv. 2022.
3. Zaim S, Chong JH, Sankaranarayanan V, et al. COVID-19 and multiorgan response. Current problems in cardiology. 2020;45(8):100618.
4. Department of Health. Coronavirus (COVID-19) case numbers and statistics: Australian Government; 2022 [cited 2022 Jan]. Available from: https://www.health.gov.au/health-alerts/covid-19/case-numbers-and-statistics#cases-and-deaths-by-age-and-sex.
5. Mukkada S, Bhakta N, Chantada GL, et al. Global characteristics and outcomes of SARS-CoV-2 infection in children and adolescents with cancer (GRCCC): a cohort study. The Lancet Oncology. 2021;22(10):1416-1426.
6. Haeusler GM, Ammann RA, Carlesse F, et al. SARS-CoV-2 in children with cancer or after haematopoietic stem cell transplant: An analysis of 131 patients. European Journal of Cancer. 2021;159:78-86.
7. Australian Technical Advisory Group on Immunisation (ATAGI). ATAGI recommendations on the use of a third primary dose of COVID-19 vaccine in individuals who are severely immunocompromised: Australian Government; 2022 [cited 2022 Jan]. Available from: https://www.health.gov.au/resources/publications/atagi-recommendations-on-the-use-of-a-third-primary-dose-of-covid-19-vaccine-in-individuals-who-are-severely-immunocompromised.
8. Hobbs CV, Woodworth K, Young CC, et al. Frequency, characteristics and complications of COVID-19 in hospitalized Infants. The Pediatric Infectious Disease Journal. 2021.
9. Yang YJ, Murphy EA, Singh S, et al. Association of Gestational Age at Coronavirus Disease 2019 (COVID-19) Vaccination, History of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection, and a Vaccine Booster Dose With Maternal and Umbilical Cord Antibody Levels at Delivery. Obstetrics & Gynecology. 2021:10.1097.
10. Kugelman N, Nahshon C, Shaked-Mishan P, et al. Maternal and Neonatal SARS-CoV-2 Immunoglobulin G Antibody Levels at Delivery After Receipt of the BNT162b2 Messenger RNA COVID-19 Vaccine During the Second Trimester of Pregnancy. JAMA pediatrics. 2021.
11. Treger S, Shiloh SR, Ben-Valid T, et al. Transplacental transfer of SARS-CoV-2 antibodies in recovered and BNT162b2-vaccinated patients. American Journal of Obstetrics & Gynecology. 2021.
12. Allotey J, Stallings E, Bonet M, et al. Clinical manifestations, risk factors, and maternal and perinatal outcomes of coronavirus disease 2019 in pregnancy: living systematic review and meta-analysis. Bmj. 2020;370.
13. Villar J, Ariff S, Gunier RB, et al. Maternal and Neonatal Morbidity and Mortality Among Pregnant Women With and Without COVID-19 Infection: The INTERCOVID Multinational Cohort Study. JAMA Pediatrics. 2021;175(8):817-826.
14. Perl SH, Uzan-Yulzari A, Klainer H, et al. SARS-CoV-2–Specific Antibodies in Breast Milk After COVID-19 Vaccination of Breastfeeding Women. JAMA. 2021;325(19):2013-2014.
15. Kelly JC, Carter EB, Raghuraman N, et al. Anti–severe acute respiratory syndrome coronavirus 2 antibodies induced in breast milk after Pfizer-BioNTech/BNT162b2 vaccination. American Journal of Obstetrics & Gynecology. 2021.
16. COVID-19 National Incident Room Surveillance Team. COVID-19 Australia: Epidemiology Report 55. Communicable Diseases Intelligence. 2021;45.
17. NSW Health. COVID-19 weekly surveillance in NSW: epidemiological week 52 ending 1 January 2022. 2022 [cited 2022 Jan]. Available from: https://www.health.nsw.gov.au/Infectious/covid-19/Documents/covid-19-surveillance-report-20220113.pdf.
18. UK Health Security Agency. SARS-CoV-2 variants of concern and variants under investigation in England. Technical briefing: Update on hospitalisation and vaccine effectiveness for Omicron VOC-21NOV-01 (B.1.1.529) 2021 [cited 2022 Jan]. Available from: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1045619/Technical-Briefing-31-Dec-2021-Omicron_severity_update.pdf.
19. Khoury DS, Steain M, Triccas J, et al. Analysis: A meta-analysis of Early Results to predict Vaccine efficacy against Omicron. medRxiv. 2021.
20. Zimmermann P, Pittet LF, Curtis N. How common is long COVID in children and adolescents? The Pediatric infectious disease journal. 2021;40(12):e482.
21. Rubens JH, Akindele NP, Tschudy MM, et al. Acute covid-19 and multisystem inflammatory syndrome in children. bmj. 2021;372.
22. Zambrano LD, Newhams MM, Olson SM, et al. Effectiveness of BNT162b2 (Pfizer-BioNTech) mRNA vaccination against multisystem inflammatory syndrome in children among persons aged 12–18 Years—United States, July–December 2021. 2022.
23. Levy M, Recher M, Hubert H, et al. Multisystem inflammatory syndrome in children by COVID-19 vaccination status of adolescents in France. JAMA. 2021.
24. Health Direct. Caring for someone with COVID-19: Australian Government Department of Health; 2021 [cited 2022 Jan]. Available from: https://www.healthdirect.gov.au/managing-covid-19/caring-for-someone-with-covid-19#child.
25. McMullan B, Britton P. Got a child with COVID at home? Here’s how to look after them: The Conversation; 2021 [cited 2022 Jan]. Available from: https://theconversation.com/got-a-child-with-covid-at-home-heres-how-to-look-after-them-166732.
26. Health Direct. Caring for people with COVID-19: Australian Government Department of Health; 2021 [cited 2022 Jan]. Available from: https://www.healthdirect.gov.au/coronavirus-covid-19-information-for-carers-faqs.
27. Department of Health. Preparing for COVID in the WA community: Government of Western Australia; 2022 [cited 2022 Jan]. Available from: https://www.healthywa.wa.gov.au/Articles/A_E/Coronavirus/Preparing-for-COVID-in-the-WA-community.
28. WA Department of Education, WA Department of Health, Telethon Kids Institute. DETECT schools study: understanding the impact of COVID-19 in Western Australian schools 2021 [cited 2022 Jan]. Available from: https://www.telethonkids.org.au/globalassets/media/documents/projects/detect-schools-study-final-report-and-appendices.pdf.
29. Racine N, McArthur BA, Cooke JE, et al. Global Prevalence of Depressive and Anxiety Symptoms in Children and Adolescents During COVID-19: A Meta-analysis. JAMA Pediatrics. 2021;175(11):1142-1150.
30. Juno J, Wheatley A. Are new COVID variants like Omicron linked to low vaccine coverage? Here’s what the science says: The Conversation; 2021 [cited 2022 Jan]. Available from: https://theconversation.com/are-new-covid-variants-like-omicron-linked-to-low-vaccine-coverage-heres-what-the-science-says-170262.
31. NSW Health. COVID-19 monitor: COVID-19 cases, variants, vaccines, hospitalisations and deaths 2022 [cited 2022 Jan]. Available from: https://aci.health.nsw.gov.au/__data/assets/pdf_file/0006/698388/20220104-COVID-19-Monitor.pdf?fbclid=IwAR0MP3YtaypZy3QNYyQHMEPgC-p02Bkz69byB3PMk-t5NtcUKsoi2W1zX_4.
32. Therapeutic Goods Administration. COVID-19 vaccine weekly safety report - 06-01-2022: Australian Government; 2022 [cited 2022 Jan]. Available from: https://www.tga.gov.au/periodic/covid-19-vaccine-weekly-safety-report-06-01-2022.
33. Singer ME, Taub IB, Kaelber DC. Risk of Myocarditis from COVID-19 Infection in People Under Age 20: A Population-Based Analysis. medRxiv. 2021.
34. Australian Technical Advisory Group on Immunisation (ATAGI), Cardiac Society of Australia and New Zealand (CSANZ), Royal Australian College of General Practitioners (RACGP), et al. Guidance on myocarditis and pericarditis after mRNA COVID-19 vaccines: Australian Government; 2021 [cited 2022 Jan]. Available from: https://www.health.gov.au/sites/default/files/documents/2021/11/covid-19-vaccination-guidance-on-myocarditis-and-pericarditis-after-mrna-covid-19-vaccines_1.pdf.
35. AusVaxSafety. COVID-19 vaccines 2021 [cited 2022 Jan]. Available from: https://ausvaxsafety.org.au/safety-data/covid-19-vaccines.
36. Bentov Y, Beharier O, Moav-Zafrir A, et al. Ovarian follicular function is not altered by SARS–CoV-2 infection or BNT162b2 mRNA COVID-19 vaccination. Human Reproduction. 2021;36(9):2506-2513.
37. Orvieto R, Noach-Hirsh M, Segev-Zahav A, et al. Does mRNA SARS-CoV-2 vaccine influence patients' performance during IVF-ET cycle? Reproductive Biology and Endocrinology. 2021;19(1):69.
38. Morris RS. SARS-CoV-2 spike protein seropositivity from vaccination or infection does not cause sterility. F&s Reports. 2021.
39. Gonzalez DC, Nassau DE, Khodamoradi K, et al. Sperm Parameters Before and After COVID-19 mRNA Vaccination. JAMA. 2021;326(3):273-274.
40. Wise M. No, COVID-19 vaccines don’t affect women’s fertility The Conversation; 2021 [cited 2022 Jan]. Available from: https://theconversation.com/no-covid-19-vaccines-dont-affect-womens-fertility-168568.
41. Edelman A, Boniface ER, Benhar E, et al. Association between menstrual cycle length and coronavirus disease 2019 (COVID-19) vaccination: a U.S. cohort. Obstetrics & Gynecology. 2022:10.1097/AOG.0000000000004695.
42. Department of Health. Clinical recommendations for COVID-19 vaccines: Australian Government; 2022 [cited 2022 Jan]. Available from: https://www.health.gov.au/initiatives-and-programs/covid-19-vaccines/advice-for-providers/clinical-guidance/clinical-recommendations.
43. Australian Technical Advisory Group on Immunisation (ATAGI). ATAGI recommendations on the use of the paediatric Pfizer COVID-19 vaccine in children aged 5 to 11 years in Australia: Australian Government; 2021 [cited 2022 Jan]. Available from: https://www.health.gov.au/sites/default/files/documents/2021/12/atagi-recommendations-on-pfizer-covid-19-vaccine-use-in-children-aged-5-to-11-years_0.pdf.
44. Debes AK, Xiao S, Colantuoni E, et al. Association of vaccine type and prior SARS-CoV-2 infection with symptoms and antibody measurements following vaccination among health care workers. JAMA internal medicine. 2021;181(12):1660-1662.
45. Olson SM, Newhams MM, Halasa NB, et al. Effectiveness of Pfizer-BioNTech mRNA Vaccination Against COVID-19 Hospitalization Among Persons Aged 12-18 Years-United States, June-September 2021. MMWR Morbidity and mortality weekly report. 2021;70(42):1483.
46. Olson SM, Newhams MM, Halasa NB, et al. Effectiveness of BNT162b2 Vaccine against Critical Covid-19 in Adolescents. New England Journal of Medicine. 2022.
47. Ali K, Berman G, Zhou H, et al. Evaluation of mRNA-1273 SARS-CoV-2 vaccine in adolescents. New England Journal of Medicine. 2021;385(24):2241-2251.
48. Pfizer. Pfizer and BioNTech provide update on ongoing studies of COVID-19 vaccine 2021 [cited 2022 Jan]. Available from: https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-provide-update-ongoing-studies-covid-19.
49. Moderna. A clinical trial of a COVID-19 vaccine in children (ages 6 months to 12 years) 2022 [cited 2022 Jan]. Available from: https://trials.modernatx.com/study/?id=mRNA-1273-P204.
50. Hause A, Baggs J, Marquez P, et al. COVID-19 Vaccine Safety in Children Aged 5–11 Years—United States, November 3–December 19, 2021. MMWR Morbidity and mortality weekly report. 2021;70:1755-1760.
51. Walter EB, Talaat KR, Sabharwal C, et al. Evaluation of the BNT162b2 Covid-19 vaccine in children 5 to 11 years of age. New England Journal of Medicine. 2021;386:35-46.