Careless question from a colleague: ‘Of course you have already seen this, but could you please answer this reader?’ Attached are some tables, which show something remarkable: the omikron variant infects people who have been vaccinated more often than people who have not. Rara, how is that possible?
Colleagues and readers often think on this point: that Keulemans knows everything, but the reality is that I stare at these kinds of figures just as glassy as anyone else. After which I in a fit of slight panic – my dear, what am I supposed to answer to this again? – dive into the professional literature and contact someone who has studied before.
Because it is definitely weird. Certainly: the omikron variant has the drawback that it can also infect people who have been vaccinated or have had an infection. In a just published, fascinating analysis Danish scientists looked at two thousand households of which a family member tested positive for the omikron variant. At home, such an infected infected an average of 30 percent of his housemates in the following week. But, very remarkable: this happened just as often with vaccinated as with unvaccinated housemates. Apparently, the virus is about equally contagious for both groups.
However, that is quite different from the fact that the omikron variant would infect vaccinated people more often. And that’s what the statistics sometimes show. Take Iceland. At the beginning of January, 2,000 for every 100,000 unvaccinated residents there tested positive for corona. For every hundred thousand vaccinated inhabitants, there were twice as many: almost four thousand. And such figures come from more countries. huh? Would the virus prefer vaccinated people – and leave unvaccinated people alone more often?
I contact epidemiologist Alma Tostmann of Radboudumc, who also knows the figures. Tostmann has a good start of an explanation: this has not only to do with the vaccine or the virus – but above all with the people involved. ‘The unvaccinated are mainly young children. And omikron has not yet circulated in the schools’, notes Tostmann. Logical, after all, it was a holiday. ‘So they haven’t been exposed yet and they haven’t been infected yet.’
The vaccinated, on the other hand, meanwhile went to the restaurant, the concert hall or the Christmas party in countries where this was possible with their corona pass. No wonder they became infected more often, says Tostmann: after all, they came into contact with many more people.
In the meantime, not much is going on in our own country, I reckon from the epidemiological weekly overviews of the RIVM. In October, when we were still under the spell of the delta variant, unvaccinated people were significantly more likely to be at risk: the chance of contracting corona was more than twice as high as among vaccinated people. The chance of becoming infected with corona, based on the figures from the test street, is now roughly the same for vaccinated and unvaccinated.
I can already hear you thinking: nice stuff, so those vaccines against omikron are useless! That would be too short sighted. After all, those who have been vaccinated are indeed protected against the disease getting out of hand, even though this is less often the case with omikron. And vaccinated people pass the virus on to others less often, according to the Danish figures: almost half as much.
Another thing that stands out in the Danish figures: those who take the booster shot are really better protected against infection, including the omikron virus. Boosted family members had only about a 25 percent chance of being infected by their infected roommate. The booster shot does not make you untouchable for the omikron virus, but you are a bit better protected than before after the extra shot.
All those numbers and percentages, are you still there? While the conclusion is quite simple, and frankly quite boring. Vaccines work. And whoever allows himself to be boosted takes an extra advantage, although you cannot rule out that you also get boosted and still become infected with the omikron variant.
In any case, the unvaccinated don’t have some mysterious force field around them to stop omikron. And if you come across a graph that shows otherwise, beware. Chances are it’s just a mirage of the stat you see there.