Fewer and fewer young children are being vaccinated. Outgoing State Secretary Maarten van Ooijen (Public Health) is concerned, he said on Friday. According to him, the Netherlands “really has high-risk percentages”. NU.nl explains the risk we run now that the vaccination rate is low.
The vaccination rate shows how many people have been vaccinated against a particular disease. The higher the vaccination rate, the more people have been vaccinated. You can receive most shots as a child through the National Vaccination Program. You will then receive injections against, for example, mumps, whooping cough or measles.
If you have been vaccinated against such a disease, you are largely or almost completely protected against it. The chance that you can still get or pass on the disease is very small.
If many people are vaccinated against a disease, the entire group is protected, including people who have not been vaccinated. This is also called herd immunity. “The more people are protected, the less well an infectious disease spreads,” a RIVM spokesperson told NU.nl.
The protected people form a kind of shield around the people who are not protected. These include, for example, very young children who have not yet been vaccinated, or people for whom the injection does not work completely well. But there are more and more people who consciously choose not to be protected.
Herd immunity only works well if enough people are protected against a virus. That number varies per disease. With corona, around 65 to 70 percent of people must be immune to also protect the unvaccinated.
But with measles, for example, this level is much higher. “Then a vaccination rate of 95 percent is required,” says the RIVM spokesperson. “This is because measles is much more contagious. A person with corona can infect between one and four people on average. With measles this is 20 to 35 possible infections.”
A disease can disappear completely if everyone is protected and no one can contract the disease anymore. “This happened, for example, with smallpox,” the spokesperson said. Smallpox used to be a dangerous disease. In the eighteenth century, one in ten children died from smallpox. In 1978, the world was declared smallpox-free after a global control program. Without the smallpox vaccine this would have been impossible.
Does the corona vaccine create herd immunity?
If the vaccination rate is below the level for herd immunity, this increases the risk of a new outbreak. The virus then spreads more easily past all protected people. It also makes it much easier to get to different places. People who are not protected, by their own choice or because the vaccine does not work properly, for example, can become ill.
The diseases that you can get a shot against have not disappeared from the face of the earth. They are rare in the Netherlands because herd immunity existed for years. But that doesn’t mean they can’t revive. Some of those diseases can also be really annoying.
The most recent measles outbreak in the Netherlands was in 2013. Then more than 2,500 people became infected. A seventeen-year-old girl died. This and previous outbreaks happened in groups that had a low vaccination rate.
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Last year, the vaccination rate against measles in the Netherlands fell below the desired 90 percent. It was also the second year in a row that the vaccination rate fell. Vaccinations are declining, especially among young children. In 2022, 6 percent fewer children were vaccinated than a year earlier.
The GGD region Hart voor Brabant is particularly striking. There, the vaccination rate among young children fell by almost 15 percentage points in one year. In Zeeland, the vaccination rate among children under the age of two is 74.8 percent. That is the lowest percentage in the Netherlands.
According to the RIVM spokesperson, this does not mean that we will immediately have a measles outbreak. “But suppose the trend continues and the vaccination rate becomes lower and lower, then that is worrying. You really want to keep that immunity, because you also want to keep the diseases that we currently do not see in the Netherlands at bay.”