‘Our results indicate that antiviral antibodies against SARS-CoV-2 did not decline within 4 months after diagnosis. We estimate that the risk of death from infection was 0.3% and that 44% of persons infected with SARS-CoV-2 in Iceland were not diagnosed by qPCR.‘
Read here (NEJM, Oct 29, 2020)
Read here the BBC story on Imperial College study that says antibodies drop rapidly