Almost half of all Australian adults had
been infected with the Covid-19 virus between January and June this year, with many of those infected in the last three months, according to a national report.
The finding comes from a serosurvey of antibodies to the virus detected in blood donations, conducted at the Kirby Institute and the National Centre for Immunisation Research and Surveillance (NCIRS).
Researchers examined 5,139 blood donations received from adults between 9 June and 18 June for anti-nucleocapsid protein antibodies, which indicate a recent infection. They also looked for anti-spike protein antibodies, which indicate immunisation.