Australia’s active hospital-based surveillance for severe childhood disease

Paediatric COVID-19 serosurveillance

SARS-CoV-2 antibodies in Australian children and adolescents 

SARS-CoV-2 infection rates in a population are an important indicator of disease severity in the community and assist in targeting vaccination at those at risk of hospitalisation and severe infection from COVID-19.

Children are a unique population in relation to understanding the spread of SARS-CoV-2 due to their lower vaccination rates compared to adults and the fact younger children were born after the onset of the pandemic, meaning they would not have been exposed to the SARS-CoV-2 virus during the early stages of the pandemic.

Between 2020 and 2023, the PAEDS network and the National Centre for Immunisation Research and Surveillance (NCIRS) conducted three serosurveys to measure the proportion of individuals in children and adolescent populations who had antibodies to SARS-CoV-2 in their blood.

The PAEDS network screened blood samples collected from children and adolescents undergoing anaesthetic procedures to evaluate SARS-CoV-2 prevalence in these population groups across Australia.

The paediatric COVID-19 serosurveillance study and findings are summarised in the video below.

 

 


Key findings

Serosurvey 1 | November 2020–March 2021

The first paediatric national SARS-CoV-2 PAEDS serosurvey was conducted prior to the COVID-19 vaccine rollout and Delta variant outbreak.

Less than 0.6% of children and adolescents were found to have been infected with SARS-CoV-2.

View the publication

 

Serosurvey 2 | June 2022–August 2022

The second paediatric national SARS-Cov-2 PAEDS serosurvey was conducted after the emergence of the Omicron variant and the COVID-19 vaccine rollout.

More than two-thirds (64%) of children had evidence of SARS-CoV-2 infection, while more than three-quarters (82%) had antibodies from infection or vaccination.

View the publication

 

Serosurvey 3 | November 2023–December 2023 

The third paediatric national SARS-CoV-2 PAEDS serosurvey was conducted after Omicron subvariants began to circulate in late 2021.

SARS-CoV-2 infection rates in children after Omicron subvariant outbreaks are unknown, given many children have asymptomatic or mild infection and are not tested. Widespread self-testing with rapid antigen tests has also meant formal reporting of COVID-19 cases is now limited and many positive cases are not being reported.

The serosurvey found 94% of children had evidence of antibodies against SARS-CoV-2. Importantly, antibodies against a wide range of Omicron subvariants were detected. 

View the study report

 

Results from these three serosurveys suggest most children and adolescents in Australia have been infected with the virus that causes COVID-19 and have broad antibody immunity across Omicron variant sub-types.

Low hospitalisation rates in this age group suggest both younger age and vaccination are protective against severe COVID-19 disease.

This work has been funded by the Australian Government Department of Health and Aged Care.

  • Project collaborators
    • National Centre for Immunisation Research and Surveillance
    • Australian Red Cross Lifeblood
    • The University of Queensland
    • Victorian Infectious Diseases Reference Laboratory
    • The Kids Research Institute
    • Murdoch Children's Research Institute
    • The Children’s Hospital at Westmead
    • Sydney Children’s Hospital, Randwick
    • Queensland Children's Hospital
    • Monash Children's Hospital
    • The Royal Children's Hospital
    • Women's and Children's Hospital
    • Perth Children’s Hospital
    • Royal Darwin Hospital

PAEDS receives funding
from the Australian government

NCIRS, Kids Research, Sydney Children’s Hospitals Network, Cnr Hawkesbury Rd & Hainsworth St, Westmead Locked Bag 4001, Westmead NSW 2145 Tel (612) 9845 1433  |  Fax (612) 9845 1418  |  ABN 53 188 579 090

We acknowledge that the National Centre for Immunisation Research and Surveillance (NCIRS) is on the land of the traditional owners the Aboriginal and Torres Strait Islander peoples, the First Australians, and recognise their culture, history, diversity and their deep connection to the land. Together, through research and partnership, we aim to move to a place of equity for all. NCIRS also acknowledges and pays respect to other Aboriginal and Torres Strait Islander nations from which our research, staff and community are drawn.

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NCIRS, Kids Research, Sydney Children’s Hospitals Network, Cnr Hawkesbury Rd & Hainsworth St, Westmead Locked Bag 4001, Westmead NSW 2145 Tel (612) 9845 1433  |  Fax (612) 9845 1418  |  ABN 53 188 579 090

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We acknowledge that the National Centre for Immunisation Research & Surveillance (NCIRS) is on the land of the traditional owners the Aboriginal and Torres Strait Islander peoples, the First Australians, and recognise their culture, history, diversity and their deep connection to the land. Together, through research and partnership, we aim to move to a place of equity for all. NCIRS also acknowledges and pays respect to other Aboriginal and Torres Strait Islander nations from which our research, staff and community are drawn.