Study: Humoral immune response to COVID-19 in Iceland

Editor's Note

This study by researchers from Iceland finds that antibodies against COVID-19 remained stable 4 months after diagnosis.

The researchers measured antibodies in serum samples from 30,576 people in Iceland, using six assays (including two pan-immunoglobulin (pan-Ig) assays).

They then tested 2,102 samples collected from 1,237 people up to 4 months after diagnosis with a quantitative polymerase-chain-reaction (qPCR) assay. They also measured antibodies in 4,222 quarantined people who had been exposed to COVID-19 and in 23,452 who were not known to be exposed.

More than 90% of qPCR-positive people also tested positive with both pan-Ig antibody assays and remained seropositive 120 days after diagnosis, with no decrease of antibody levels.

The researchers also estimated that 0.9% of Icelanders were infected with COVID-19, and that the infection was fatal in 0.3%.

In an accompanying editorial, ( https://www.nejm.org/doi/full/10.1056/NEJMe2028079 ) scientists from Harvard University and the National Institutes of Health note that this study provides hope that host immunity to COVID-19 may not be fleeting and may be similar to that elicited by most viral infections.