The seroprevalence of SARS-CoV-2-specific antibodies in Australian children: a cross sectional study

  1. Archana Koirala
  2. Jocelynne McRae
  3. Philip N Britton
  4. Marnie Downes
  5. Shayal A Prasad
  6. Suellen Nicholson
  7. Noni E Winkler
  8. Matthew V N O’Sullivan
  9. Fatima Gondalwala
  10. Cecile Castellano
  11. Emma Carey
  12. Alexandra Hendry
  13. Nigel Crawford
  14. Ushma Wadia
  15. Peter Richmond
  16. Helen S Marshall
  17. Julia E Clark
  18. Joshua R Francis
  19. Jeremy Carr
  20. Adam Bartlett
  21. Brendan McMullan
  22. Justin Skowno
  23. Donald Hannah
  24. Andrew Davidson
  25. Britta S von Ungern-Sternberg
  26. Paul Lee-Archer
  27. Laura L Burgoyne
  28. Edith B Waugh
  29. John B Carlin
  30. Zin Naing
  31. Nicole Kerly
  32. Alissa McMinn
  33. Guillian Hunter
  34. Christine Heath
  35. Natascha D’Angelo
  36. Carolyn Finucane
  37. Laura A Francis
  38. Sonia Dougherty
  39. William Rawlinson
  40. Theo Karapanagiotidis
  41. Natalie Cain
  42. Rianne Brizuela
  43. Christopher C Blyth
  44. Nicholas Wood
  45. Kristine Macartney
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Abstract

Background

Following reduction of public health and social measures concurrent with SARS-CoV-2 Omicron emergence in late 2021 in Australia, COVID-19 case notification rates rose rapidly. As rates of direct viral testing and reporting dropped, true infection rates were most likely to be underestimated.

Objective

To better understand infection rates and immunity in this population, we aimed to estimate SARS-CoV-2 seroprevalence in Australians aged 0-19 years.

Methods

We conducted a national cross sectional serosurvey from June 1, 2022, to August 31, 2022, in children aged 0-19 years undergoing an anesthetic procedure at eight tertiary pediatric hospitals. Parents or guardians of children and adolescents under 18 years provided written consent and participants aged 18-19 years provided their own consent. Participant questionnaires were administered, and blood samples tested using the Roche Elecsys Anti-SARS-CoV-2 total spike and nucleocapsid antibody assays. S and N seroprevalence adjusted for geographic and socioeconomic imbalances in the participant sample compared to the Australian population was estimated using multilevel regression and poststratification within a Bayesian framework.

Results

Blood was collected from 2,046 participants (median age: 6.6 years). Adjusted seroprevalence of spike-antibody was 92.1 % (95% credible interval (CrI) 91.0-93.3%) and nucleocapsid-antibody was 67.0% (95% CrI 64.6-69.3). In unvaccinated children spike and nucleocapsid antibody seroprevalences were 84.2% (95% CrI 81.9-86.5) and 67.1% (95%CrI 64.0-69.8), respectively. Seroprevalence increased with age but was similar across geographic distribution and socioeconomic quintiles.

Conclusion

Most Australian children and adolescents aged 0-19 years, across all jurisdictions were infected with SARS-CoV-2 by August 2022, suggesting rapid and uniform spread across the population in a very short time period. High seropositivity in unvaccinated children informed COVID-19 vaccine recommendations in Australia.

Funding

Australian Government Department of Health and Aged Care.

Article activity feed

  1. Version published to 10.1101/2024.03.03.24303672v1 on medRxiv