As of Tuesday, Iceland had tested more than 17,900 people for the virus — nearly 5% of its population. And while its National University Hospital tests people who are high-risk or show symptoms, nearly half of Iceland’s tests have been conducted by biopharma company deCODE Genetics, focusing on the the wider population…

“The results of the additional tests performed by deCODE have given an indication that efforts to limit the spread of the virus have been effective so far,” the government wrote last week, adding “testing in the general population will continue to elicit a much clearer picture of the actual spread of the SARS-CoV-2 virus in Iceland.”

Some of the revelations have been stark. Although fewer than 1% of the tests came back positive for the virus, the company’s founder Dr. Kári Stefánsson told CNN that around 50% of those who tested positive said they were asymptomatic, confirming multiple studies that show that asymptomatic, or mildly symptomatic, people have played an important role in spreading the virus.