Abstract A third SARS-CoV-2 infection wave has affected Germany from March 2021 until April 24th, until the ´Bundesnotbremse´ 
introduced nationwide shutdown measures. The ´Bundesnotbremse´ is the technical term which was used by the German gov-
ernment to describe nationwide shutdown measures to control the rising infection numbers. These measures included mainly 
contact restrictions on several level. This study investigates which effects locally dispersed pre- and post-´Bundesnotbremse´ 
measures had on the infection dynamics. We analyzed the variability and strength of the rates of the changes of weekly case 
numbers considering different regions, age groups, and contact restrictions. Regionally diverse measures slowed the rate of 
weekly increase by about 50% and about 75% in regions with stronger contact restrictions. The 'Bundesnotbremse' induced 
a coherent reduction of infection numbers across all German federal states and age groups throughout May 2021. The coher-
ence of the infection dynamics after the 'Bundesnotbremse' indicates that these stronger measures induced the decrease of 
infection numbers. The regionally diverse non-pharmaceutical interventions before could only decelerate further spreading, 
but not prevent it alone. Keywords  COVID · SARS-CoV-2 · Shutdown · Spreading · Germany Keywords  COVID · SARS-CoV-2 · Shutdown · Spreading · Germany Keywords  COVID · SARS-CoV-2 · Shutdown · Spreading · Germany Infection (2021) 49:1331–1335 
https://doi.org/10.1007/s15010-021-01713-7 Infection (2021) 49:1331–1335 
https://doi.org/10.1007/s15010-021-01713-7 BRIEF REPORT BRIEF REPORT Effectiveness of extended shutdown measures 
during the ´Bundesnotbremse´ introduced in the third SARS‑CoV‑2 
wave in Germany Andreas Schuppert1 · Katja Polotzek2 · Jens Karschau2 · Christian Karagiannidis3 Received: 29 June 2021 / Accepted: 5 October 2021 / Published online: 20 October 2021 
© The Author(s) 2021 *	 Andreas Schuppert 
	
aschuppert@ukaachen.de Regional and age‑stratified analysis 
of the infection dynamics overall dynamics without deconvolution of the respective 
effects of diverse measures. overall dynamics without deconvolution of the respective 
effects of diverse measures. f
In our previous analysis [10], we assessed NPIs in the 
context of spreading by different patterns of coherent infec-
tion dynamics across the sixteen federal states in Germany 
and different age groups. For our analysis, we used the daily reports on age-federal 
state stratified incidences from the RKI Dashboard [1]. We 
split the third wave into three different phases, separated 
by well-defined events: exponential growth during March 
2021 before the Easter holidays, slowing down during the 
Easter period and a reduction phase after initiation of the 
“Bundesnotbremse”. The linear shape of the case numbers in 
semi-logarithmic scaling (Fig. 1) during the rising phase vis-
ualizes exponential growth, where the different slopes corre-
spond to different effective reproduction numbers. The data 
around spring break are strongly influenced by testing and 
reporting issues around the Easter holidays with huge report-
ing gaps. Hence, we considered the mean slopes between 
beginning and end of the Easter holidays for our analysis 
(Fig. 1). As in parallel to NPI’s, by March the majority of 
those ones aged over 80 years were vaccinated, we focused 
our attention to the age groups between 35 and 79 years [5]. For suppression of the weekly anomalies of infection 
incidence data due to non-continuous reporting in Ger-
many, we use moving 7-day means of case numbers for 
six age groups across all 16 federal states, normalized to 
100.000 inhabitants within each age group. To compare 
absolute change rates per day, we use finite differences 
from the growth phase interval March 17–March 29, the For our analysis, we used the daily reports on age-federal 
state stratified incidences from the RKI Dashboard [1]. We 
split the third wave into three different phases, separated 
by well-defined events: exponential growth during March 
2021 before the Easter holidays, slowing down during the 
Easter period and a reduction phase after initiation of the 
“Bundesnotbremse”. The linear shape of the case numbers in 
semi-logarithmic scaling (Fig. 1) during the rising phase vis-
ualizes exponential growth, where the different slopes corre-
spond to different effective reproduction numbers. The data 
around spring break are strongly influenced by testing and 
reporting issues around the Easter holidays with huge report-
ing gaps. Diverse rise of infection dynamics 
throughout Germany through
Germany 
related to 
The sprea
April for m
beginning
highly vul
Most of th
and non-p
key appro
Analys
infection 
action of 
as seasona
ous bundl
efficacy o
mode of s
growth in
efficiency
Andreas Schuppert and Katja Polotzek contributed in the same 
way. *	 Andreas Schuppert 
	
aschuppert@ukaachen.de
 *	 Christian Karagiannidis 
	
Christian.Karagiannidis@uni-wh.de
	
Katja Polotzek 
	
Katja.Polotzek@uniklinikum-dresden.de
	
Jens Karschau 
	
Jens.Karschau@uniklinikum-dresden.de
1	
Institute for Computational Biomedicine, JRC 
for Computational Biomedicine, RWTH Aachen University, 
University Hospital Aachen, Aachen, Germany
2	
Centre for Evidence‑Based Healthcare, University 
Hospital Carl Gustav Carus and Carl Gustav Carus Faculty 
of Medicine, Technische Universität Dresden, Dresden, 
Germany
3	
Department of Pneumology and Critical Care Medicine, 
Cologne‑Merheim Hospital, ARDS and ECMO Centre, 
Kliniken Der Stadt Köln, Witten/Herdecke University 
Hospital, Cologne, Germany Andreas Schuppert and Katja Polotzek contributed in the same 
way. Germany was affected by a strong third SARS-CoV-2 wave 
related to the emerging alpha variant in spring 2021 [1, 2]. The spreading dynamics showed reduced case numbers by 
April for multiple reasons. The German vaccination program 
beginning in the end of December 2020 initially focused on 
highly vulnerable groups [3], in particular, the elderly [4, 5]. Most of the population has, thus, not yet been immunized 
and non-pharmaceutical interventions (NPI) remained the 
key approach for spreading control [5–8].fi *	 Andreas Schuppert 
	
aschuppert@ukaachen.de *	 Christian Karagiannidis 
	
Christian.Karagiannidis@uni-wh.de Katja Polotzek 
Katja.Polotzek@uniklinikum-dresden.de Jens Karschau 
Jens.Karschau@uniklinikum-dresden.de Analyses of NPI efficiency for breaking SARS-CoV-2 
infection dynamic is important but hampered by the inter-
action of a multitude of impacts beside vaccination such 
as seasonality, test strategies, anticipation, and heterogene-
ous bundles of NPIs set in place locally [9]. Moreover, the 
efficacy of NPIs depends on the context of the dominating 
mode of spreading, for example nearly linear or exponential 
growth in infection dynamics [10]. Hence, analyses of NPI 
efficiency can hardly be performed by statistical analysis of 1	
Institute for Computational Biomedicine, JRC 
for Computational Biomedicine, RWTH Aachen University, 
University Hospital Aachen, Aachen, Germany 2	
Centre for Evidence‑Based Healthcare, University 
Hospital Carl Gustav Carus and Carl Gustav Carus Faculty 
of Medicine, Technische Universität Dresden, Dresden, 
Germany 3	
Department of Pneumology and Critical Care Medicine, 
Cologne‑Merheim Hospital, ARDS and ECMO Centre, 
Kliniken Der Stadt Köln, Witten/Herdecke University 
Hospital, Cologne, Germany (0121 3456789)
3 1332 A. Schuppert et al. Table 1   Prior to the 
´Bundesnotbremse´ across the 
German federal states a variety 
of different contact restrictions 
was in place depending on the 
recorded seven-day incidence 
per 100,000 inhabitants (* 
7day/100 k) within the state Regional and age‑stratified analysis 
of the infection dynamics Hence, we considered the mean slopes between 
beginning and end of the Easter holidays for our analysis 
(Fig. 1). As in parallel to NPI’s, by March the majority of 
those ones aged over 80 years were vaccinated, we focused 
our attention to the age groups between 35 and 79 years [5]. f
The local NPIs implemented during the raise of the third 
wave in Germany greatly differed regionally (Table 1). The 
aim of the current work was, therefore, to determine the 
effects of the extended shutdown set in place by April 24, 
2021, by comparing the infection dynamics before and after 
this date across the federal states and age groups. These 
measures, also called ´Bundesnotbremse´ (verbatim ´federal 
emergency break´), induced nationwide control of SARS-
CoV-2 infection dynamics by introducing consistent con-
tact reductions across all states and were associated with an 
ongoing reduction of daily new cases. The individual contact 
reductions of the “Bundesnotbremse” had been established 
beforehand in some federal states allowing us to study the 
effect of coherent measures in contrast to local measures on 
control of nation-wide pandemic spreading. For suppression of the weekly anomalies of infection 
incidence data due to non-continuous reporting in Ger-
many, we use moving 7-day means of case numbers for 
six age groups across all 16 federal states, normalized to 
100.000 inhabitants within each age group. To compare 
absolute change rates per day, we use finite differences 
from the growth phase interval March 17–March 29, the The above number of allowed contacts serves a one example of the diversity of non-pharmaceutical inter-
ventions throughout Germany (Suppl. Figure 2). Regional and age‑stratified analysis 
of the infection dynamics Figure 3 for color code.) case of 7-day incidences below and above 100 7d/100.000 
inhabitants as a marker for the overall strength of local 
restrictions set in place before and within slowing down 
phase (Table 1). case of 7-day incidences below and above 100 7d/100.000 
inhabitants as a marker for the overall strength of local 
restrictions set in place before and within slowing down 
phase (Table 1). The effects of NPIs before and after the 
´Bundesnotbremse´ We found that the dynamics of the growth phase has been 
reduced throughout the slowing down phase for all age 
groups, followed by a remarkable downturn in the reduc-
tion phase (Fig. 2). However, the p values for the difference 
of change rates between growth phase and slowing down 
phase as well as slowing down phase and reduction phase 
show clear significance for the observed dynamics, strati-
fied by age groups (Suppl. Figure 1A, Wilcoxon test) and 
even when stratified by federal states who differed in testing 
strategies for children (Suppl. Figure 1B, two-sided I test). Notably, the decrease of dynamics after the ´Bundesnot-
bremse´ exceeds by far the decrease induced by the slowing 
down phase before. An exception is the state of Hamburg, 
where the decrease induced by the ´Bundesnotbremse´ is not 
significant (p = 0.98). Hamburg, however, had installed hard 
contact restrictions, including a curfew, three weeks prior to 
the ´Bundesnotbremse´ explaining the insignificant effect of 
the ´Bundesnotbremse´ in Hamburg.i Fig. 1   The 7-day incidence per 100.000 inhabitants for the 16 Ger-
man federal states depicts three different phases during the third wave 
in Germany. Prior to spring break 2021 we observed very different 
dynamics among the states, which harmonized to a similar rate of 
reduction across all states after unified NPIs throughout Germany 
starting from end of April 2021. The linear slopes in semi-logarith-
mic scaling emphasize the exponential behavior. Further, first the 
slopes are different and disordered, later they coincide and keep their 
order. (See Suppl. Figure 3 for color code.) A significant decrease of infection dynamics has started 
around the Easter period, about three weeks before the 
´Bundesnotbremse´. To assess the potential impact of 
NPI’s on the slowing down phase, we analyzed the daily 
growth dynamics within the slowing down phase in the 
federal states with moderate to strong contact restric-
tions before homogenization by the ´Bundesnotbremse´ 
(Fig. 3). Remarkably, the daily growth rates within the slowing down phase interval March 29–April 24 and the 
reduction phase interval April 24–May 14, 2021. Within 
each interval we calculated the mean growth rate per day 
for each federal state and age group using the respec-
tive 7-day means resulting in the mean change rate as 
described above. The effects of NPIs before and after the 
´Bundesnotbremse´ For assessment of the impact of local 
contact restrictions set in place before Easter period, we 
used the highly diverse regulations for private contacts in slowing down phase interval March 29–April 24 and the 
reduction phase interval April 24–May 14, 2021. Within 
each interval we calculated the mean growth rate per day 
for each federal state and age group using the respec-
tive 7-day means resulting in the mean change rate as 
described above. For assessment of the impact of local 
contact restrictions set in place before Easter period, we 
used the highly diverse regulations for private contacts in -7.5
-5.0
-2.5
0.0
2.5
5.0
7.5
Mean daily change rate
0-4y
5-14y
15-34y 35-59y 60-79y
>80y
Exponential Growth Phase
(17.3. - 29.03.21)
Slowing Down Phase
(29.3.- 24.4.21)
Reduction Phase
(24.4.-14.5.21)
Fig. 2   The mean of the daily rate of change of the 7-day incidences 
among all German states (bar height) was positive across all age 
groups prior to the ´Bundesnotbremse´ and negative afterwards. The 
low rate of the elderly reflects the immunization among this popula-
tion group that was prioritized in the beginning of the German vac-
cination program. In the reduction phase we found less variance (thin 
lines, measured by standard error of the mean) across the states than 
in the slowing down phase characterized by various NPIs Slowing Down Phase
(29.3.- 24.4.21) Fig. 2   The mean of the daily rate of change of the 7-day incidences 
among all German states (bar height) was positive across all age 
groups prior to the ´Bundesnotbremse´ and negative afterwards. The 
low rate of the elderly reflects the immunization among this popula- tion group that was prioritized in the beginning of the German vac-
cination program. In the reduction phase we found less variance (thin 
lines, measured by standard error of the mean) across the states than 
in the slowing down phase characterized by various NPIs tion group that was prioritized in the beginning of the German vac-
cination program. In the reduction phase we found less variance (thin 
lines, measured by standard error of the mean) across the states than 
in the slowing down phase characterized by various NPIs tion group that was prioritized in the beginning of the German vac-
cination program. Regional and age‑stratified analysis 
of the infection dynamics Different states implemented stricter regulations, such as 
contact restrictions regarding different households or numbers of persons, or curfews at night-time across 
the entire state, each only in hot spot counties or across the entire state
Contact restrictions in the Ger-
man federal states
Incidence < 100 * 7day/100 k
Incidence ≥ 100 * 7day/100 k
 < 5 persons
 ≥ 5 persons
 < 5 persons
 ≥ 5 persons
Baden-Württemberg
x
x
Bayern
x
x
Berlin
x
x
Brandenburg
x
x
Bremen
x
x
Hamburg
x
x
Hessen
x
x
Mecklenburg-Vorpommern
x
x
Niedersachsen
x
x
Nordrhein-Westfalen
x
x
Rheinland-Pfalz
x
x
Saarland
x
x
Sachsen
x
x
Sachsen-Anhalt
x
x
Schleswig-Holstein
x
x
Thüringen
x
x The above number of allowed contacts serves a one example of the diversity of non-pharmaceutical inter-
ventions throughout Germany (Suppl. Figure 2). Different states implemented stricter regulations, such as 
contact restrictions regarding different households or numbers of persons, or curfews at night-time across 
the entire state, each only in hot spot counties or across the entire state The above number of allowed contacts serves a one example of the diversity of non-pharmaceutical inter-
ventions throughout Germany (Suppl. Figure 2). Different states implemented stricter regulations, such as 
contact restrictions regarding different households or numbers of persons, or curfews at night-time across 
the entire state, each only in hot spot counties or across the entire state The above number of allowed contacts serves a one example of the diversity of non-pharmaceutical inter-
ventions throughout Germany (Suppl. Figure 2). Different states implemented stricter regulations, such as 
contact restrictions regarding different households or numbers of persons, or curfews at night-time across 
the entire state, each only in hot spot counties or across the entire state 1 3 Effectiveness of extended shutdown measures during the ´Bundesnotbremse´ introduced in the… 1333 Fig. 1   The 7-day incidence per 100.000 inhabitants for the 16 Ger-
man federal states depicts three different phases during the third wave 
in Germany. Prior to spring break 2021 we observed very different 
dynamics among the states, which harmonized to a similar rate of 
reduction across all states after unified NPIs throughout Germany 
starting from end of April 2021. The linear slopes in semi-logarith-
mic scaling emphasize the exponential behavior. Further, first the 
slopes are different and disordered, later they coincide and keep their 
order. (See Suppl. The effects of NPIs before and after the 
´Bundesnotbremse´ During 
the reduction phase after the ´Bundesnotbremse´ we observed simi
lar negative relative changes across all states with decreased stand
ard error of the mean (thin lines) compared to the mean (bar heights)
Those states with early contact reduction set in place experienced
slightly faster decreased (B, C) B
-4
-2
0
2
4
Mean relative change per day (%)
0-4y
5-14y
15-34y 35-59y 60-79y
>80y
Slowing Down Phase
(Incidence >100•7d/100k*) -4
-2
0
2
4
Mean relative change per day (%)
Federal States with Contacts
limited to <5 persons
Federal States with Contacts
limited to ≥5 persons
0-4y
5-14y
15-34y 35-59y 60-79y
>80y
Slowing Down Phase
A
(Incidence <100•7d/100k*) B C
-4
-2
0
2
4
Mean relative change per day (%)
Federal States with Contacts
limited to <5 persons
0-4y
5-14y
15-34y 35-59y 60-79y
>80y
Federal States with Contacts
limited to ≥5 persons
Reduction Phase
(Incidence <100•7d/100k*) C
-4
-2
0
2
4
Mean relative change per day (%)
0-4y
5-14y
15-34y 35-59y 60-79y
>80y
Reduction Phase
(Incidence <100•7d/100k*) D
-4
-2
0
2
4
Mean relative change per day (%)
0-4y
5-14y
15-34y 35-59y 60-79y
>80y
Reduction Phase
(Incidence >100•7d/100k*) C D D Fig. 3   During the period of heterogeneous NPIs (Suppl. Table 1) the 
mean daily relative change per age group differed among the states 
(Suppl. Figure 1). Those states with a less than five allowed contacts 
already at 7-day incidences per 100.000 inhabitants (* 7day/100 k) 
below 100 exhibited slower rates of increase (A). So did states with 
a stronger reduction of contacts when 100 was reached (B). During the reduction phase after the ´Bundesnotbremse´ we observed simi-
lar negative relative changes across all states with decreased stand-
ard error of the mean (thin lines) compared to the mean (bar heights). Those states with early contact reduction set in place experienced 
slightly faster decreased (B, C) statistical significance testing showing highly significant 
correspondence of hard contact regulations and slowing 
down of infection dynamics (Suppl. Figure 2). We could 
not find any significant correspondence between the con-
tact regulations and infection dynamics in the growth and 
reduction phases. slowing down phase have been significantly higher in fed-
eral states with moderate contact regulations (red bars) 
compared to federal states with strong contact regulations 
(orange bars) (Fig. 3A, B). The effects of NPIs before and after the 
´Bundesnotbremse´ In the reduction phase we found less variance (thin 
lines, measured by standard error of the mean) across the states than 
in the slowing down phase characterized by various NPIs 1 3 1334 A. Schuppert et al. -4
-2
0
2
4
Mean relative change per day (%)
Federal States with Contacts
limited to <5 persons
Federal States with Contacts
limited to ≥5 persons
0-4y
5-14y
15-34y 35-59y 60-79y
>80y
Slowing Down Phase
A
B
C
D
(Incidence <100•7d/100k*)
-4
-2
0
2
4
Mean relative change per day (%)
Federal States with Contacts
limited to <5 persons
0-4y
5-14y
15-34y 35-59y 60-79y
>80y
Federal States with Contacts
limited to ≥5 persons
Reduction Phase
(Incidence <100•7d/100k*)
-4
-2
0
2
4
Mean relative change per day (%)
0-4y
5-14y
15-34y 35-59y 60-79y
>80y
Federal States with Contacts
limited to <5 persons
Federal States with Contacts
limited to ≥5 persons
Slowing Down Phase
(Incidence >100•7d/100k*)
-4
-2
0
2
4
Mean relative change per day (%)
0-4y
5-14y
15-34y 35-59y 60-79y
>80y
Federal States with Contacts
limited to <5 persons
Federal States with Contacts
limited to ≥5 persons
Reduction Phase
(Incidence >100•7d/100k*)
g. 3   During the period of heterogeneous NPIs (Suppl. Table 1) the 
ean daily relative change per age group differed among the states 
uppl. Figure 1). Those states with a less than five allowed contacts 
ready at 7-day incidences per 100.000 inhabitants (* 7day/100 k) 
elow 100 exhibited slower rates of increase (A). So did states with 
stronger reduction of contacts when 100 was reached (B). The effects of NPIs before and after the 
´Bundesnotbremse´ This difference disappeared 
after the ´Bundesnotbremse´ where we found strong 
reduction of incidence independent of prior local regula-
tions (Fig. 3C, D). These observations are confirmed by 1 3 1335 Effectiveness of extended shutdown measures during the ´Bundesnotbremse´ introduced in the… Supplementary Information  The online version contains supplemen-
tary material available at https://​doi.​org/​10.​1007/​s15010-​021-​01713-7. Supplementary Information  The online version contains supplemen-
tary material available at https://​doi.​org/​10.​1007/​s15010-​021-​01713-7. 10. Schuppert A, Polotzek, K., Schmitt,J., Busse,R., Karschau, J., 
Karagiannidis, Ch. . Different spreading dynamics throughout 
Germany during the second wave of the COVID-19 pandemic: 
link to public health interventions. Lancet Regional Health 
Europe. 2021. https://​doi.​org/​10.​2139/​ssrn.​38049​89 Acknowledgements  We are very grateful for the data collection and 
provision of all public health data, especially at the local public health 
offices, at the federal state institutions and at the Robert Koch Institute. 11. https://​www.​dwd.​de/​DE/​presse/​press​emitt​eilun​gen/​DE/​2021/​
20210​429_​deuts​chlan​dwett​er_​april​2021_​news.​html. Accessed 1 
Oct 2021 Funding  Open Access funding enabled and organized by Projekt 
DEAL. 12. https://​www.​dwd.​de/​DE/​presse/​press​emitt​eilun​gen/​DE/​2021/​
20210​531_​deuts​chlan​dwett​er_​mai20​21_​news.​html. Accessed 1 
Oct 2021 The impact of the ´Bundesnotbremse´ Ministry of Research and Education, during the conduct of the study. All others have no COI to declare. Our findings on spatially age stratified analyses of the third 
wave in Germany show remarkable differences in infec-
tion dynamics confirming our earlier results concerning 
the second wave. The infection dynamics after the ´Bun-
desnotbremse´ were characterized by a steep, coherent 
decline. In contrast, the slowing down phase before the 
´Bundesnotbremse´ resulting from school holidays, diverse 
contact restrictions during Easter period and also a chang-
ing behavior of the population showed only a slight and 
inhomogeneous decrease of infection spreading. As vacci-
nation made rapid progress primarily within the age group 
80 + and age group 60–79 years, the infection dynamics 
differences might be driven by vaccination progress. Moreover, testing strategies have been changed within the 
period for preschool and schoolchildren, such that data 
for the age groups below 14 years may be affected by 
changes in testing strategies, less by NPI’s. Remarkably, 
this decline was highly significant in age groups between 
15 and 59, where vaccination had minor impact within this 
timeframe. Within the timespan of our analysis in April 
and May 2021 weather has been extraordinarily cold and 
wet with similarly cold temperatures in April and May [11, 
12]. Hence we believe that effects of seasonality did not 
contribute significantly to the observed nationwide decline 
of the infections in May compared to April 2021. Open Access  This article is licensed under a Creative Commons Attri-
bution 4.0 International License, which permits use, sharing, adapta-
tion, distribution and reproduction in any medium or format, as long 
as you give appropriate credit to the original author(s) and the source, 
provide a link to the Creative Commons licence, and indicate if changes 
were made. The images or other third party material in this article are 
included in the article's Creative Commons licence, unless indicated 
otherwise in a credit line to the material. If material is not included in 
the article's Creative Commons licence and your intended use is not 
permitted by statutory regulation or exceeds the permitted use, you will 
need to obtain permission directly from the copyright holder. To view a 
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