11 June 2020

Danish Antibody Test Shows with Great Accuracy Whether People Have Been Infected with Covid-19

Coronavirus

Researchers from the University of Copenhagen, Rigshospitalet and Novo Nordisk have developed two new, accurate antibody tests for Covid-19. The researchers believe that one test is ideal for tracking the spread of infection in the population, while the other is well suited for investigating the type of antibodies over time.

Blood samples
Photo: Novo Nordisk Foundation

Two newly developed antibody tests can – with great accuracy – determine whether or not a person has had a Covid-19 infection. That has been confirmed in a just completed validation of the tests.

The tests have been developed from the ground up in close collaboration between Rigshospitalet, the University of Copenhagen and Novo Nordisk with support from the Carlsberg Foundation and the Novo Nordisk Foundation. They may become a significant contribution to the monitoring of the spread of disease during the Covid-19 pandemic and to the antibody response at the individual level and in society in general.

These results show that our tests are able to detect antibodies in the majority of the persons who have been infected with Covid-19. However, we do not yet know if people are truly protected against the infection if they have developed antibodies against the virus, or for how long the antibodies will continue to be developed in the body. 

Peter Garred.

Together with researchers from Novo Nordisk, Associate Professor Mikkel-Ole Skjødt from the Department of Immunology and Microbiology, Senior Researcher Rafael Bayarri-Olmos and Professor Peter Garred's research group from the Diagnostics Centre at Rigshospitalet and the Department of Clinical Medicine at the University of Copenhagen have been responsible for the development of the two types of antibody tests.

Uses the Virus's Spike Protein

In recent weeks, the researchers have examined blood from persons who have previously been diagnosed with Covid-19 infection to see if they have now developed antibodies to the Covid-19 virus. The results show that approx. 97 percent of all people with a positive throat swab test have developed antibodies to the Covid-19 virus. This is consistent with new, similar studies made in China and the US.

‘These results show that our tests are able to detect antibodies in the majority of the persons who have been infected with Covid-19. However, we do not yet know if people are truly protected against the infection if they have developed antibodies against the virus, or for how long the antibodies will continue to be developed in the body. This is something that needs further studies’, says Peter Garred.

Lately, the researchers from the University of Copenhagen, Rigshospitalet and Novo Nordisk have been working intensively to develop various versions of the tests to see which versions work the best and to find out which parts of the virus are most suitable to capture the most accurate antibody response.

They have come to the conclusion that the part that works best is an area of the virus's so-called Spike protein, called RBD (receptor binding domain). RBD is also the area of the virus where it differs most from other coronaviruses, and it is what the virus uses to penetrate our cells. Therefore, it makes good sense to use this area for the test itself.

Novo Nordisk has produced high-quality reagents for the antibody tests, contributed to thorough control measures and ensured that the tests will be offered on a large scale, while the researchers at Rigshospitalet have mainly done molecular groundwork, tested prototypes and examined clinical samples.

Serves Various Purposes

The two types of tests which are both using the so-called ELISA principle, make use of a blood test and must be performed in a laboratory. In this way, they differ from the less sensitive finger prick tests. Also, they are made with two different purposes in mind.

One test, called sandwich ELISA, can be used to determine whether or not people have developed antibodies against the Covid-19 virus, for instance in a large population screening. The other test, called direct ELISA, can be used to investigate the type of antibody (IgM, IgA and IgG) against the Covid-19 virus in people’s blood.

While the sandwich test would be ideal for tracking the spread of infection in the society, the direct test could be used to investigate the type of antibodies over time, to select donors whose antibodies may be used to treat Covid-19 patients, and to investigate whether vaccines against the Covid-19 virus actually create an antibody response.

‘In the future, once our knowledge of Covid-19 has improved, our tests may hopefully also be used to predict who has actually become immune to the virus’, says Peter Garred.

However, he emphasises that more research is needed before they can be used for this type of counselling.

Contact

Further information can be obtained from Professor Peter Garred from Rigshospitalet and the University of Copenhagen by e-mailing: peter.garred@regionh.dk

Press Contact

Rigshospitalet, Jesper Sloth Møller:

+45 5144 6367 Jesper.sloth.moeller@regionh.dk