An antibody study carried out by the Finnish Institute for Health and Welfare (THL) has found that the number of people infected with coronavirus in the Hospital District of Helsinki and Uusimaa (HUS) may be many times higher than the confirmed number of cases.
Antibody studies can be used to collect information on the share of the population that have been infected with coronavirus. THL studied the prevalence of antibodies in blood samples of persons who had undergone laboratory tests for various reasons in the Hospital District of Helsinki and Uusimaa.
“The study is the first preliminary assessment of the extent to which the coronavirus epidemic has spread in the HUS area, and the share of people who may have had the mild or asymptomatic version of the disease,” says Merit Melin, Senior Researcher at the Finnish Institute for Health and Welfare.
The sampling includes just over 400 samples
The samples were collected from HUSLAB’s clinical chemistry laboratories over a period of three consecutive weeks 23 March – 12 April 2020. The sampling included a total of 442 samples from men and women between the ages of 15 and 90, who had given a blood sample for reasons other than anyinfection. These surplus samples from laboratory tests were examined without personal identifiers.
Two different tests were performed to determine the presence of antibodies. A commercial rapid test was used for sample screening, the performance of which was tested at THL before the study. In addition, all positive results were verified with THL’s own test. The THL confirmation test measures the ability of antibodies to neutralise the virus and provides a very reliable result.