For reference, there are no antibody studies which conclude that serpositivity for COVID natural infection is anywhere near 30% in 2020.
It was 3.5% in July 2020, and 20% in May 2021, from testing ~1.5 blood donations, which is roughly consistent with other studies, and parallels sensitivity in the UK.
It was 3.5% in July 2020, and 20% in May 2021, from testing ~1.5 blood donations, which is roughly consistent with other studies, and parallels sensitivity in the UK.
[1] https://jamanetwork.com/journals/jama/fullarticle/2784013