The Australian COVID-19 Serosurveillance Network is conducting a series of regular serological surveys during 2022 among Australian blood donors (aged 18 years and over) to provide estimates of the proportion of the population that have SARS-CoV-2 antibodies (i.e., seroprevalence).
The surveys are being conducted every 13 weeks (approximately) using residual blood donations, with two serosurvey rounds completed to date. Results for blood donations received between 23 February and 3 March 2022 (Round 1) and the survey methods can be found here. This report describes the results for blood donations received between 9 June and 18 June 2022 (Round 2).
- The prevalence of anti-spike antibodies was very high (99%) across all jurisdictions. Seroprevalence was very high across all age groups and within the four jurisdictions for which sample size was large enough to calculate age-specific rates: Victoria, NSW, Queensland, and WA. These findings are consistent with observations from Round 1.
- The prevalence of anti-nucleocapsid antibodies increased from 17% in Round 1 to 46% in Round 2. Antibody prevalence increased in all states and territories, including Western Australia, where seroprevalence increased from less than 0.5% to 38%.
- Overall, the highest positivity was in the 18–29-year-old age group, at 62%. This age-specific pattern was also observed within Victoria, NSW, Queensland and WA.