The results pour cold water on the prospect of growing collective or herd immunity, with Red Cross officials saying that large-scale immunity among the Belgian population was still “a distant dream” at this stage.
Federal health institute Sciensano has been carrying serological tests on residual blood samples of donors across Belgium since March, provided by the Red Cross in Flanders, Brussels and Wallonia.
As part of the study, the Red Cross provides Sciensano with 1,500 residual blood samples every two weeks.
The latest results also show that the rate at which the average blood donor was building immunity is stagnating, with a comparison to last month’s results, when 4.3% of donors had developed antibodies, revealing a marginal increase.
According to Sciensano spokesperson Yves Van Laethem, the slow rate of antibody development can be attributed to citizens’ lack of exposure to the virus resulting from the lockdown.
Donors’ blood is examined by health authorities because they belong to a segment of the population which is “healthy by definition and is between 18 and 75 years old,” Van Laethem told reporters Friday.
By analysing the blood samples, health authorities can assess the impact of the virus in that particular population group.
“This low rate of antibody development will now be something to follow up on in the context of the measures to lift the lockdown,” he said.
A recent Sciensano serological study of health personnel also revealed that immunity levels among health care personnel were low, with less than 10% of health staff had developed antibodies against the virus.