Why Do Vaccination Rates Differ So Much Within Germany?

Maximilian Ambros / Michael Frenkel - January 24, 2022

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The COVID-19 pandemic is one of the deadliest pandemics ever documented throughout history. It has had a firm grip on our lives for nearly two years. Countries all over the world are facing consecutive waves of infections. Fortunately, unprecedented efforts by the pharmaceutical industry have led to the development of vaccines at lightning speed. These vaccines have been available since the end of 2020 and many developed countries have been equipped with sufficient supplies since the second half of 2021. But governments around the world continue to struggle not only with the virus and its variants but also with insufficient vaccination rates. At this pace, herd immunity cannot be achieved.

In Germany, after a steep rise in vaccination rates from 0 to 65 percent by August 2021, progress in the vaccination campaign slowed. Within Germany, the vaccination rate continues to vary significantly across the board. For example, only 63.5 percent of all Saxons received at least one vaccination by January 6, 2022, while 87.7 percent of Bremen's population is already completely vaccinated. Causal factors for these substantial differences in vaccination rates are manifold.

What are the reasons behind the significant variation in vaccination rates within Germany?

Survey data collected thus far indicates that vaccination-based decisions depended especially on income and population density. However, such survey data is often biased as those who oppose vaccinations may not share their honest opinion. This phenomenon is known as social desirability. Respondents do not disclose their true beliefs because they assume that these would not be met with social approval.

WHU researchers therefore did not work with survey data. Instead, they used a new data set which depicts current vaccination numbers in German counties. They also examined - at the county level - the influence of the COVID-19 mortality rate, physician density, population density, proportion of the population older than 65, and proportion of foreigners in the population on the rate of initial vaccinations. The study established that vaccination rates can be explained particularly well by the following five factors:

1. Counties that are or were heavily affected by COVID-19 show higher vaccination rates.
2. Higher physician density leads to higher vaccination rates.
3. Higher population density leads to higher vaccination rates, indicating a "city effect.”
4. The higher the average age of the population in a county, the higher the vaccination rate.
5. Location plays an important role. New federal states (formerly belonging to the GDR) have significantly lower vaccination rates than older states, meaning that variations in vaccination rates can also be found at state level. This explains, the significant discrepancy between the rates in Saxony and Bremen.

From these results, recommendations for action can be derived for political decision-makers to take measures to increase the efficiency and efficacy of the vaccination campaign.

Literature reference and methodology

For the study "What Determines COVID-19 Vaccination Rates in Germany?" data was collected in more than 300 German counties. In addition to local vaccination rates, physician density, population density, COVID-19 mortality rates, the proportion of the population over 65 years of age, and foreigners were also considered.  

• Ambros, M./Frenkel, M. (2022): The Determinants of COVID-19 Vaccination Rates in Germany, in: Journal of Economics and Statistics (JBNST), accepted for publication.