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Antibody study confirms very low levels of COVID-19 in Australian children in early 2021

Results from a unique Australian antibody study, published in the Medical Journal of Australia, confirm that very few children and adolescents (<0.5%) had COVID-19 by early 2021 (i.e. before the Delta outbreak). 

The study, which aimed to detect COVID-19–specific antibodies in children aged 0–19 years, was conducted at seven hospitals in the Australian Paediatric Active Enhanced Disease Surveillance (PAEDS) network during 3 November 2020 – 12 March 2021. 

A repeat antibody study, using the same methodology, is being conducted from June to July 2022 to better understand the SARS-CoV-2 infection rates in children and adolescents since the Delta and Omicron waves. 

Antibodies are created when the body’s immune system responds to infection, and can be detected for months afterwards. Antibody studies (also called seroprevalence surveys) can provide a more complete picture of the number of people infected with SARS-CoV-2, the virus that causes COVID-19, than reported case numbers. This is because many people who have COVID-19 experience only mild symptoms, or even none at all, and may not always come forward for testing.

The findings of this study are similar to those of other Australian antibody studies that mainly sampled adults. Healthy children are often underrepresented in seroprevalence studies that rely on the use of samples from blood tests or from blood donors. This study used a unique opportunistic, consent-based method of blood sampling from patients undergoing elective surgery at PAEDS network hospitals. 

Age-specific antibody studies provide insights into viral transmission and can help guide policies on vaccination. Since 2021, there has been increased transmission of COVID-19 with high case notification rates in Australia.

Read the full publication here