Vaccine sceptics often point to the fact that even people who are vaccinated against coronavirus can still get infected. However, new data from several of Germany's federal states has now suggested that the unvaccinated are much more at risk of infection - and of developing a serious course of the disease.

Unvaccinated people at higher risk of infection

Coronavirus data from several federal states has revealed that unvaccinated people are at a higher risk of being infected than those who have been vaccinated. In Saxony, for example, the state with the lowest full vaccination rate (under 60 percent), the seven-day incidence rate for vaccinated people stands at 64 cases per 100.000 people. However, for those who were not (fully) vaccinated, this figure stands at 1.823 cases per 100.000 people, some 28 times higher.

There are some discrepancies between states, especially those with higher vaccination rates. However, the data still clearly shows that infection rates are much higher amongst those who remain unvaccinated. Taking Bremen - the state with the highest vaccination rate (79,3 percent as of Tuesday) - as another example, the seven-day incidence rate for vaccinated people is 41 per 100.000 people, whereas the unvaccinated incidence rate stands at 261.

Only a few other states give a seven-day incidence rate value for both unvaccinated and vaccinated people, namely Thuringia, Bavaria and Saxony-Anhalt. It is important to note that there are no uniform rules between the states that classify who is vaccinated and unvaccinated, for example in some states, like Saxony, anyone with an unknown vaccination status, who has been infected with the virus, is put down as not (fully) vaccinated.

Making sense of the numbers

Carsten Watzl, Secretary-General of the German Society for Immunology, has described the infection numbers relating to vaccination status as “a bit skewed." Certainly, there are a number of different factors that can affect coronavirus data. Unvaccinated people and younger students are frequently obliged to get tested under the country’s 3G rules, so that they may be able to do certain things like sit down in a restaurant or enter school classrooms. This means there is a higher chance of an infection being detected, whereas those who are vaccinated are not obliged to get tested for these things, and so infections are more likely to go undetected.

However, according to Watzl, even with these factors the numbers do demonstrate that unvaccinated people are at a higher risk of infection. "It is therefore still correct that unvaccinated people become infected much more frequently than vaccinated people," he said. Watzl also drew attention to the number of people infected with coronavirus currently suffering in hospital.

These hospitalisations make it very clear which group is more at risk of serious complications arising from infection. The latest data from the Robert Koch Institute (RKI) shows that the incidence rate of hospitalisation amongst unvaccinated people aged 18 to 59 years old is six times higher than the incidence rate amongst vaccinated people of the same age group. For people aged 60 and over, the incidence rate was 4,7 times higher for unvaccinated people.

RKI urges caution

The RKI has urged people to interpret the numbers with caution, and has warned that infection rates, vaccination rates and different test behaviour could lead to bias. The RKI itself excludes all cases where a patient’s vaccination status isn’t known or if they are only partially vaccinated.