Fifth of Dutch blood donors have Covid antibodies

21 percent of blood donors in the Netherlands have antibodies for the coronavirus SARS-CoV-2 in their blood, according to an ongoing study by blood bank Sanquin. Antibodies indicate that the person either had the coronavirus at some point, or was vaccinated against it.

The provinces of Limburg and Noord-Brabant have the most blood donors with coronavirus antibodies at 26 percent. In the rest of the Netherlands, about 20 percent of donors have antibodies. 

"Unfortunately, you can't say in general that someone with antibodies is also guaranteed to be immune," said Hans Zaaijer, medical microbiologist at Sanquin. "But this clearly indicates how many people have been infected from the first wave. The RIVM can use this data to advise on further policy."

About 2 thousand samples of donated blood are tested for coronavirus antibodies on a weekly basis, to use as an indicator for the spread of Covid-19 in the Netherlands. Blood donors are not entirely representative of the population, but these figures are "strongly indicative", a Sanquin spokesperson said to NU.nl.