The figures are striking, because a year ago only one in five elderly had experienced an infection. ‘We are so careful that we do not get the virus’, says medical microbiologist and research leader Hans Zaaijer, himself in his sixties. ‘But then came the omikron variant. Wham!’
In barely three quarters of a year, the percentage of blood donors with the fingerprints of a corona infection in the blood shot up. 59 percent of the elderly have been demonstrably infected. In young people, even 90 percent must have experienced an infection.
stark contrast
All in all, 77 percent of all blood donors have now had corona. The actual number is probably even higher, Zaaijer thinks. ‘Groups where the vaccination coverage was lower and where there were more infections, such as people with a migration background, are underrepresented among our blood donors.’
Also striking is the high concentration of antibodies in the blood of the elderly. Of all age groups, people over 65 now have the most antibodies. That is ‘a stark contrast’ with last year, says Zaaijer, when the elderly had very little of the virus-killing proteins in their blood in the winter, and were therefore very vulnerable to infection. ‘The booster arrived just in time. We did look for the edge last year.’
The fact that many elderly people are now extra well protected is due to the extra injection rounds: first the booster, then the extra, ‘fourth’ jab, last summer. There is no reason at all to skip the new booster round, says Zaaijer. “A quarter of all donors have not yet encountered the coronavirus, especially the elderly. For most people, the booster, specially adapted for omikron, is absolutely recommended.’
Better protection
‘The younger, the more often infected. And the older, the more often vaccinated’, sums up RIVM chief epidemiologist Susan van den Hof, after perusing the new figures. ‘These figures confirm what we have known for a long time, and what we also see in other studies: after the arrival of omikron, many people became infected with the virus.’
The new figures also confirm that those who have had an infection have more antibodies than those who were vaccinated alone. Not surprising, says Van den Hof. As a rule, anyone who got corona had already been vaccinated. And numerous studies have shown that vaccination plus a normal infection – or vice versa – provides better protection against re-infection than vaccination alone.
The number of infected is expected to rise further in the coming months. After all, the virus is spreading again, with new omikron variants that can avoid antibodies a little better.