Sydney had triple the COVID-19 infections diagnosed, study finds

Concerning research highlighting the asymptomatic nature of the virus. Around 7,450 Sydneysiders were likely infected with COVID-19 in its first wave in March and April – three-and-a-times the official 2,118 cases diagnosed at the time, according to a study led by the National Centre for Immunisation Research and Surveillance, the Kirby Institute and the NSW Health Department. The researchers tested 5,339 de-identified blood samples from late April to early June which showed that while Sydney’s infection rate was lower than many cities overseas, it was still much higher than the testing at the time. 0.79% of the pregnant women tested were found to have antibodies that indicated they had been infected with SARS-CoV-2, the virus that causes COVID-19. 0.29% of blood donors had the antibodies, while for people who had a pathology test for other reasons than COVID, the rate was 0.15%. Extrapolated across Sydney’s five million population, the results suggest that 7,450 or one in 670 people were infected. Other studies have found similar results. A study in New York found 14% of its population had antibodies by the end of April, 10 times the number diagnosed at the time. While the analysis is yet to be peer-reviewed, it’s a sign of how easily people who have no or only mild symptoms can go undetected.