Covid booster shot "very effective" in preventing serious illness: RIVM

The third vaccination is "very effective" in preventing severe consequences of Covid-19, public health institute RIVM found in its first study into the booster campaign. The booster protects 97 percent against hospitalization and 98 percent against intensive care admission, the institute reported. However, it should be noted that the study was conducted when the Delta variant was dominant. Less is known about the effectiveness against the Omicron variant.

Between November 19 and January 13, the chance of ending up in hospital with Covid-19 was 33 times smaller for people who had a booster shot compared to unvaccinated people. For people who received only the first two vaccinations, the risk of hospitalizations was five times higher than for those who received the third shot.

The booster shot turned out to be even more effective in preventing admission to the intensive care unit. Compared to unvaccinated people, the chance of needing ICU treatment was 50 times smaller in the past months. People who had two shots were four times more likely to end up in the ICU than people with a booster.

The booster shot, therefore, protects people more against hospital admissions. Those who only had two vaccinations were 85 percent protected against hospitalization. Older people experienced relatively more protection from the booster shot.

In the period that the RIVM studied, most hospital admissions were caused by an infection with the Delta variant of the coronavirus. "An estimate of the vaccine effectiveness against hospitalization is not yet possible," the RIVM said. According to the institute, data from the United Kingdom showed that protection against the Omicron variant is lower than against the Delta variant, also with a booster.

On Wednesday, research by the RIVM showed that of the people who are eligible for a booster shot, 3.1 percent do not intend to get one, and 8.6 percent are still unsure.