The percentage of blood donors with antibodies against coronavirus rose from 21% to 32% within the last month, blood donation company Sanquin said on Tuesday.

This is the highest increase since Sanquin started monitoring coronavirus antibodies in blood donations.

The biggest increase was among donors aged 61 to 70, more than 40% of whom now have antibodies, thanks to the vaccination programme.

‘At the same time, we see that the antibodies in donors aged 18-30 are also steadily increasing, to over 30%, but that is due to ongoing infections,’ Sanquin said.

Women are much more likely than men to have antibodies, but this is because far more women work in the healthcare sector than men and have also been vaccinated.

In order to achieve some level of herd immunity, some 67% of people must have antibodies in their blood, Sanquin said.

According to the government’s coronavirus dashboard, some 5.6 million doses of vaccine have been used in the Netherlands since the campaign started in mid January.