Antibodies Persist for Four Months after Infection; Infection Fatality Ratio 0.3%, Much Higher in Older Patients.

This Icelandic study measured a variety of IgG and IgM antibodies to SARS-CoV-2 in six groups of Icelanders who had either never been tested or had tested negative and in two groups of Icelanders who had tested positive and had recovered. They weighted the sample by age and sex to estimate the number of Icelanders [...]