Belgium's hoped-for herd immunity against Covid 'not possible,' says expert

Belgium's hoped-for herd immunity against Covid 'not possible,' says expert
Credit: Belga

The hoped-for herd immunity against Covid-19, in which most of the population in Belgium will be immune to the coronavirus, is "impossible," says microbiologist Emmanuel André (KU Leuven).

While the only scenario at the start of the pandemic was avoiding infection and getting vaccinated, the situation has become a lot more complex now, André said in an interview with De Morgen on Monday.

"We can no longer lump everyone together in terms of vulnerability and protection, even as most figures are rising again," he said, adding that one-third of the population has been infected, and way more have been vaccinated.

While the most fragile people (those with a weakened immune system) could receive an extra booster after the summer, "the risk at the individual level is now even more different for other target groups than before."

André stressed that even though the Belgian population has already built up considerable immunity, "the herd immunity we once hoped for is not possible, but we can prevent serious illness in the vast majority of people."

Still, people have not been vaccinated and have not (yet) been infected, the risk of severe infection remains. "Omicron, and perhaps the following variants too, are not as mild as we would have liked. For those who are completely unprotected, the rule is still: avoid infection and get vaccinated."

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For most people, however, the situation is no longer as black-and-white as it once was, he added. "If you received three doses of the vaccine, and were infected one or more times on top of that, you are at a high level of protection, but it will diminish in the coming months."

Deliberately seeking out infection – as many people are reportedly doing now – is never recommended, especially for those who are a bit older, whose immune system does not work as well, or who are considered as a high-risk group.

"And for anyone else: do not go looking for an infection, it will come anyway," André said. "As a society, we have made the informed choice that most people are allowed to drop their precautions, and to behave as is permitted today. If you do not get infected in those circumstances, it means that your immunity is still excellent or that Covid is not present in your environment."

Still, he said, everyone will come into contact with the virus at some point and their immunity will decrease over time. "It is not smart to pretend that it is a choice. It will happen, but an acquired infection will also boost your immunity again."

Going 130 km/h instead of 120

Currently, Belgium is in 'code yellow' on the coronavirus barometer, even though the number of daily hospital admissions is too high: nearly 200 per day, instead of a maximum of 75.

"We knew that politicians would use the barometer like this. We are going a bit too fast – we are allowed 120 km/h but we are driving 130 – but we're aware of that," André said. "Despite the fact that we still see dramatic situations in every wave, the risk of death today is much lower than in all previous waves and this will continue to decrease."

For the coming months and years, he predicts more waves and variants to come, even though strict measures like those of the past two years will likely not remain necessary. "Society learns how to adapt each time and our healthcare system has more weapons now than it did two years ago. But the virus will not go away for the next few decades and who knows how long."

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