Vaccine hesitancy continues to pose a challenge not only for low- and middle-income countries, but also for many high-income countries, many of which are confronted with significant within-country variation in vaccine take-up. This column examines the potential role of historical factors and provides evidence that, in the context of Germany, county-level vaccination rates today can be explained in part by differences in counties’ exposure to the naturopathic movement, a medicine-critical movement that emerged in the second half of the 19th century.
Vaccines are considered one of the most important developments in modern medicine. Yet, despite their effectiveness in preventing diseases and deaths, vaccine hesitancy is widespread globally (Larson et al. 2014, Lane et al. 2018, de Figueiredo et al. 2020, Solís Arce et al. 2021). While vaccine hesitancy, and more generally the underutilisation of health services, has been extensively studied in the context of low- and middle-income countries (e.g. Banerjee et al. 2010, 2022; for a review, see Dupas and Miguel 2017), vaccine hesitancy in high-income countries has received less attention.
This changed with the coronavirus disease 2019 (COVID-19) pandemic, as scepticism about newly developed vaccines became a major obstacle in containing the spread of the virus and in reducing hospitalisations and deaths in high-income countries (e.g. Voth et al. 2021, Mohammed et al. 2022, Nasreen et al. 2022, Sabatini et al. 2022, Agrarwal et al. 2024). As Figure 1 illustrates, in Western Europe, average vaccination rates against COVID-19 may mask considerable geographic variation in vaccine hesitancy within countries. Interestingly, for some countries, such as Germany and the UK, the variation in regional vaccination rates is greater than the variation in vaccination rates across the countries shown in Figure 1 (which varied between 68% and 82%). This suggests that national policies can explain only part of the observed variation in vaccine hesitancy in Western Europe.
Figure 1 Between- and within-country variation in COVID-19 vaccination rates for Western European countries
Notes: This figure shows, based on OECD data from February 2022, the average COVID-19 vaccination rate for Western European countries as dots. It also indicates the within-country variation as bars and reports the lowest and highest regional value. Number of regions: 22 (Spain), 5 (Denmark), 21 (Italy), 3 (Belgium), 13 (France), 16 (Germany), 2 (Iceland), 7 (Norway), 9 (Austria), 10 (UK), 7 (Sweden), 1 (Luxembourg), 7 (Switzerland).
Source: https://www.oecd.org/regional/recovery-platform.htm.
In recent work (Binzel and Link 2023), we try to explain the heterogeneity in vaccination rates within countries. The focus is on Germany where, at the county level, vaccination rates against COVID-19 varied between 50% and 91% by late 2021. 1 We argue that part of the observed differences in vaccine hesitancy today have historical roots. More specifically, we argue that in the context of Germany, vaccine hesitancy today can be traced back in part to the naturopathic movement (Naturheilbewegung) of the second half of the 19th century.
At the time, the naturopathic movement was by far the largest ‘life-reform movement’ (Lebensreformbewegung) and the most important movement critical of medicine (medizinkritische Bewegung), including vaccinations, in the German Empire (Regin 1995, Dinges 1996). 2 Naturopathic associations aimed to influence how the formal healthcare system operated, for example by lobbying for the recognition of naturopathic healers and for naturopathic therapies to be covered by local sickness funds. They also maintained a range of activities to promote naturopathic norms and values in local communities, such as providing medical equipment and counselling, organising public lectures, and disseminating the magazine Der Naturarzt (Regin 1995, 1996, Thießen 2017). Even though the movement lost its significance at the beginning of the 20th century, it is plausible that these activities altered institutions and norms more permanently, leading to higher vaccine hesitancy in these counties.
To study the movement’s long-term impact on vaccination rates today, we digitised data on the number of naturopathic associations from the Hygienischer Volkskalender of 1900 (Gerling 1900). In total, there were 889 associations with 180,288 members, out of which 571 were located within Germany’s current borders. We compute a county’s total number of naturopathic associations and their members in 1900. Out of the 401 counties, 171 had at least one association in 1900 (42.6%). These had on average 438 members, with 10% of these counties counting more than 1,000 members in total. We combine this data with available historical, geographic, and modern data. 3
Panel (a) of Figure 2 shows a map with the number of naturopathic associations in 1900 at today’s county level. It illustrates that the naturopathic movement was particularly strong in East Germany, especially in counties located in the southern part of East Germany, in Saxony and Thuringia. Panel (b) shows a map with counties’ COVID-19 vaccination rates. It documents striking differences between West and East Germany, with counties with low vaccination rates concentrated in the southern part of East Germany. Together, the maps suggest a negative relationship, at the county level, between the strength of the naturopathic movement and COVID-19 vaccination rates. This relationship holds when we account for basic and modern controls.
Figure 2 The number of naturopathic associations in 1900 and COVID-19 vaccination rates
Notes: Panel (a) shows the total number of naturopathic associations in 1900 at the level of today’s counties. Panel (b) shows counties’ COVID-19 vaccination rates at the end of 2021. At that time, there was no longer a vaccination prioritisation policy in place and vaccines were sufficiently available. The thick black line indicates the border between the Federal Republic of Germany (West Germany) and the German Democratic Republic (East Germany).
If taken at face value, our estimate implies that counties with the average number of naturopathic associations in 1900 have a 2.7 percentage points lower COVID-19 vaccination rate today than counties that were historically not exposed to the movement. We obtain similar results when we (i) use other measures for the strength of the movement in 1900 (e.g. membership numbers), (ii) add further controls, and (iii) restrict the sample to counties that had least one naturopathic association in 1900. Finally, we obtain qualitatively similar results when we consider counties’ measles vaccination rates. 4 This suggests that our results are not specific to COVID-19 vaccinations, but hold more generally.
It is plausible that counties with a stronger naturopathic movement differ along other, unobservable characteristics that may be correlated with vaccine hesitancy today. If so, our estimate may falsely attribute part of the observed differences in vaccination rates to differences in the strength of the naturopathic movement. We therefore next make use of the fact that early on, Heilbäder (spas) influenced the development of the naturopathic movement and the creation of associations through hydropathy and that many such Heilbäder were founded on water sources with a high content of sulfuric acid (Flechsig 1883, Mosse 1889). This is confirmed by data we digitised on the existence of sulfur water baths: counties with sulfuric acid sources are significantly more likely to have such a bath in 1865. While the actual establishment of such baths is endogenous, a county’s distance to the closest native sulfur may create plausibly exogenous variation in a county’s historic exposure to the movement. Using this variable as an instrumental variable (IV) for the number of associations in 1900 and controlling for a range of geographic controls, we can confirm our earlier results.
Having established a (causal) relationship between the strength of the naturopathic movement in 1900 and vaccination rates today, we then provide evidence for two channels. First, we show that the naturopathic movement changed how the local formal healthcare system operated. We digitised data on alternative practitioners in 1909 and show that counties with a stronger naturopathic movement had more alternative practitioners.
Second, we provide evidence for an international transmission of norms. Drawing on two rounds of the European Values Survey that include geographic identifiers (2008 and 2017), we show that for the full sample, but not for the sample of immigrants, respondent’s confidence in the healthcare system is lower when they live in a county that had more naturopathic associations in the past.
In addition, we find no significant influence of the movement on respondents’ confidence in the healthcare system in the Polish European Values Survey. This is consistent with the idea that with the flight and (wild) expulsion of ethnic Germans from counties that became part of Poland after World War II, naturopathic norms and values were lost.
To conclude, this paper provides empirical evidence for the importance of historical roots of vaccine hesitancy. From a policy perspective, these results suggest that national efforts to increase vaccine uptake, such as information campaigns, monetary incentives, nudges and vaccine mandates (e.g. Shah and Chang 2021, Bloom et al. 2022, Campos-Mercade et al. 2021, Athey et al. 2023) may not be sufficient to boost vaccination rates in some regions or may even backfire.
By documenting the existence of East–West differences in socioeconomic outcomes around 1900, we also contribute to recent research showing that East–West differences in socioeconomic outcomes were already prevalent before Germany’s division in the aftermath of World War II (Mergele et al. 2020).
Source : VOXeu
