Danish blood tests shed new light on the coronavirus
Preliminary results from antibody testing must be taken with a number of caveats, the professor emphasizes.
Tests from 1,487 Danish blood donors may help shed new light on how deadly coronavirus really is.
The World Health Organization, WHO, has estimated that the figure is around one to three percent. But it may turn out to be high, according to calculations made at Rigshospitalet.
– We arrive at a much lower figure of 1.6 per thousand. So if we have 1,000 Danes who have had this infection, there are one to two who have died with it, says Henrik Ullum, a consultant and professor at Rigshospitalet.
He, along with colleagues, underwent blood tests from just under 1,500 blood donors who received blood on Monday. The blood has been used to test for coronavirus antibodies and preliminary results shed new light on the number of infected.
High darkness over infected
Antibodies are formed when an infection with the virus is over. And it turns out that 22 of the 1,487 blood donors have formed antibodies.
– If we assume that the blood donors are representative of the entire population, it is equivalent to 127,000 people in Denmark having been infected.
Thus, when 203 Danes are declared dead today with coronavirus, it gives a mortality of 0.16 percent – or 1.6 per thousand.
But blood donations are not representative of the entire population because they are generally healthier than the total population.
– Therefore, the actual number infected throughout the Danish population may well be greater, says Henrik Ullum, who emphasizes that the figures are preliminary and must be read with caution.
Blood donors come to donate blood and are healthy and healthy. Therefore, we may underestimate how many have been infected. We can also overestimate it if they have traveled more or been more ill than the background population, says Henrik Ullum.
So far 57,535 people in Denmark have been tested for coronavirus. 5,386 have been tested positive.
The Danish Serum Institute has constantly counted on a considerable number of dark figures and yesterday estimated that the actual number of infected persons could be somewhere between 70,000 and 150,000.
After Easter, the Capital Region begins to screen all employees who have patient contact because they have formed antibodies to coronavirus.
New figures must be reserved
The results of the antibody tests must be taken with a number of caveats.
The test doesn’t seem perfect either. There are several of those tested who have been infected with coronavirus where the test has not been able to see it.
– That’s actually 23 percent in our numbers. But we have gone into that uncertainty in the figures I just presented, says Henrik Ullum.
At the same time, Henrik Ullum emphasizes that you are not necessarily fully protected against a new round of coronavirus infection, even though you have been through it once.
– The last element of uncertainty is that if you have had a very mild infection, you get a very weak antibody response. It is not necessarily antibodies that make you fully immune, so we cannot say that you cannot get this infection again, he says, adding:
“On the other hand, we know that a viral infection, which you have already fought once, is reasonably well protected against. So the risk of getting it again is probably lower and the risk of getting a severe infection will also be lower.”