New test: At least 11 out of 100 have antibodies to the coronavirus in the Stockholm area

Karolinska University Hospital and Karolinska Institutet have collaborated to produce a new antibody test in the fight against covid-19. In recent weeks, researchers have conducted test tests in two sessions of 100 persons each. The tests used blood from blood donors. The second round, conducted last week, showed that at least 11 people out of 100 had developed antibodies to the coronavirus. 

Jan Albert is a consultant in clinical microbiology at Karolinska University Hospital and has worked on the preparation of the samples. Tomorrow the tests will be put into operation on a larger scale.

 - We are happy to have a test that we know is okay. It is not 100 percent sensitive, it has sensitivity of 70-80 percent. Some will test negative even though they have had it. But no one will test false positives. Those we have tested that should be negative have been, says Jan Albert.

The first blood donor test is not a facet, but can be seen as an indication of the extent - even though it is believed to be higher. For example, given the accuracy of the test and that it was only performed on a person who has been healthy from covid-19 for at least two weeks.

- One cannot draw conclusions about the exact percentages, but we know that the 11 percent have had it. It is too little for a research report, but too important to sit and hold on, says Jan Albert, and says that further research remains.

- We will continue to get better and better clarity. We will be looking at more blood donors this week. It would be best to have a large random selection, says Jan Albert.

Tom Britton, professor of mathematical statistics, says that a third of Stockholmers have already become infected. According to his calculations, the spread is still large, but slowly declining.

 - In about a month, the worst spread of infection will be over in Stockholm. Then we will be close to the so-called herd immunity, Tom Britton tells SVT.

Although Tom Britton's calculations do not fully match the tests conducted by Jan Albert, Tom Britton believes that there are no contradictions between the two studies. 

 - Both studies have uncertainties. If my estimation is slightly high and the other a little too low, the truth is probably somewhere in between, says Tom Britton.