In 2016 and 2017, selected primary schools in the rural German state of Brandenburg conducted a two-day first-aid training program coordinated by the registered non-profit organization Pépinière. The trainers were specifically trained paramedics, medical students, and volunteers from other health professions. First-aid training took place on two consecutive school days (in total 10–12 hours of teaching), followed by an assessment on the third day, which was also regarded as a repetition of the training. Methods and first results have been published previously (Humbsch et al., 2023).

The anonymous two-year follow-up assessment using self-report questionnaires on paper for the evaluation was conducted in three of these schools (schools A–C) between March 2019 and February 2020. In the same regions as the intervention schools, we recruited students of similar ages from three primary schools (schools D–F) without previous formal school-based first-aid training. In Brandenburg, Germany, primary schools include six grades (i.e., usually children from 6 to 12 years of age). For the intervention group, longitudinal data is available, but not for the control group.

Out of the six primary schools that were recruited for the initial short-term evaluation of the school-based training workshop, we were able to include three schools (labeled as Schools A–C) for the two-year follow-up assessment of the present study. Among the remaining three schools, two with a focus on integrating children with special needs were excluded because their training differed from the other four intervention schools. We did not consider it to be comparable with the training course for primary schools in general. The third school was excluded because the principal denied participation in the two-year follow-up assessment without giving any reason.

The follow-up assessment took place two years after the primary school-based first-aid training course. Only students up to 11 years of age were included as the older students who were in grades five and six had left primary school since the training took place.

The initial planning of the study did not include a two-year follow-up assessment. However, in addition to the before-and-after comparisons with the students from the intervention group, we additionally included similarly aged students from three other primary schools (Schools D–F), which did not have any school-based first-aid training course. These three schools were from the same rural regions as the intervention schools (A–C). Due to a post-hoc decision to include a control group, randomization of the participating schools was not possible.

For the follow-up of Schools A–C (intervention) and the assessment in Schools D–F (control), the parents were notified in advance via a standardized letter of information about the study’s aims. We explained that it was an anonymous assessment “about important health related topics” to avoid parents preparing their children specifically for first aid and resuscitation topics. The parents’ consent was handled by each school individually. Some schools considered the questionnaire as part of the regular classes, while others considered it as an add-on to the regular class and gave the parents the choice to deny their children’s participation in the questionnaire assessment.

The main exposure was the school-based first-aid training (two years ago among students at Schools A–C), the reference category was no such training (control group, Schools D–F). As main outcomes, we evaluated five important resuscitation and first-aid parameters:

Knowledge of:

Furthermore, we descriptively evaluated the willingness of the students to help in an emergency situation as an additional outcome.

The ethical review board of the university hospital Charité – Universitätsmedizin Berlin (Berlin, Germany) approved the study (application number: EA2/123/18). The individual questionnaires included the names of schools, but were answered anonymously by the students.

We followed an explorative approach for this evaluation. The basic sociodemographic characteristics were presented by absolute and relative frequencies for categorical variables and by median, 25th and 75th percentile, minimum, and maximum for continuous variables.

For the four main outcomes, logistic regressions were performed. We present the crude results and results adjusted for age, sex, and language spoken at home as potential confounders. Results are presented as odds ratios (OR) with 95% confidence intervals (CI). Since all results are considered exploratory, there is no level of significance, and we did not adjust for multiple testing. For the fifth endpoint (knowledge of all three resuscitation parameters), odds ratios were not calculated because the number of cases was too small. For outcomes, we compared the changes in the five first-aid parameters (listed above) from baseline to two years after the school-based training course among students of the intervention group. Statistical analyses were performed using IBM SPSS Statistics 28 (Armonk, New York, USA).

In the intervention group (Schools A–C), 716 students aged up to 11 years took part in the two-day school-based first-aid training in 2017. Out of these, 115 former students from fifth and sixth grade had moved on to secondary school (i.e., grade 7 and higher in this German state) and thus were excluded from our two-year follow-up assessment. Of all primary school students, 239 were excluded because they had left school since the training took place or were not present on the day of our two-year evaluation (e.g. due to sickness). Thus, in total, 360 students (60.1% of 599 grade 1–4 students) took part in the two-year follow-up assessment and were included in the present analysis (Figure 1). Fifty-five students (across all three schools), mainly those who joined after the training course two years prior, were allowed to fill out the questionnaire but were excluded from the present analysis.

Out of 459 students in the control group, one student was excluded due to participation in the same first-aid training at a different school. This resulted in 458 students from schools D–F without school-based first-aid training as the control group for the present analysis.

At baseline, the intervention group included 599 students with a mean age of 8.4 years (standard deviation (SD) 1.4). At the two-year follow-up, we were able to include 360 students with a mean age of 10.4 years (SD 1.3) (Table 1). Over the two years, the proportion of male students stayed constant at 49%. At baseline in the intervention group, there were slightly more students who did not speak German at home (5%) than in the two-year follow-up (3%).

The control group (without school-based first-aid training) included 458 students with a mean age of 10.1 years (SD 1.3) and slightly more male students (56%) than the intervention group. Among the control group students only 2% did not speak German at home.

The location of the compression point was correctly answered by 29% of the intervention group students immediately after the two-day training and 51% at the two-year follow-up (schools A–C). In the control group (schools D–F) 30% answered it correctly (Table 2 and Figure 2). After adjusting for age, sex, and language spoken at home, the odds of correctly identifying the compression point were twice as high in the two-year follow-up intervention group as in the control group. The odds of knowing the compression point were higher among female vs. male students. Each one-year increase in age was associated with 1.3 times higher odds of a correct response. There was no difference between students who spoke German vs those who did not speak German at home (Table 3).

In the intervention group, the compression depth was answered correctly by 49% immediately after the two-day training and 8% at the two-year follow-up (schools A–C). In the control group (schools D–F), only 3% answered it correctly (Figure 2). After adjusting the odds of correctly answering the compression depth they were three times as high in the two-year follow-up intervention group as in the control group. There were no considerable differences regarding the socio-demographic factors in the adjusted analysis (Table 3).

In the intervention group, the compression rate was answered correctly by 43% immediately after the two-day training and 7% at the two-year follow-up (schools A–C). Only 4% of the control group (schools D–F) answered this correctly (Figure 2). After adjusting, a tendency toward higher odds of correctly identifying the compression rate was observed in the intervention group compared with the control group. Regarding the socio-demographic factors, only increasing age was associated with higher odds of a correct response (Table 3).

Only about 1% of the students in the intervention group and about 0.2% of the students in the control group answered all three questions correctly in the two-year follow-up assessment. Two years before (i.e. immediately after the school-based two-day training) 14.5% of the intervention group were able to answer all three CPR questions correctly.

The percentage of students who thought that they would not help a person in an emergency situation stayed at about 1% across all groups. Immediately after the two-day training and at the two-year follow-up in the intervention group (Schools A–C), almost three-quarters would help everybody in an emergency situation. In the control group (Schools D–F without school-based first-aid training) slightly more than three-quarters would help everybody in an emergency situation (Table 2).

The emergency telephone number was correctly answered by approximately 90% in all groups (Table 2). After adjusting, there was no considerable difference between the two-year follow-up intervention and the control group. Girls (vs. boys), and students who spoke German at home (vs. no German) answered it correctly more often (Table 3).

Primary school students who participated in a school-based first-aid training course were more likely to know important resuscitation parameters two years later than students from comparable schools without such training. However, the two questions on compression depth and compression rate were each answered correctly by less than 10%, compared to almost half of all students immediately after they participated in the first-aid course. The knowledge of the emergency phone number was similarly high (about 90%) in both the intervention and control groups. Furthermore, the willingness to help others in an emergency situation was comparable with over 80% in both groups.

The ABC for Life program in the United Kingdom is a first-aid training course that targets a similar age group (10–12 years) as in our study. A single-choice questionnaire of 22 items was used to evaluate the knowledge retention after six months following a two-hour first-aid training of 79 students. The question about the compression point was correctly answered by 85% and the compression rate by 78% directly after training. The results of the follow-up after six months were not presented individually by question but summarized in a score. The score declined significantly but stayed at a higher level than the baseline score (Connolly et al., 2007). These baseline values were almost twice as high as our results directly after the two-day first-aid training. In our questionnaire, we only used open questions, which are generally harder to answer than multiple-choice questions with one correct answer out of three options.

Bánfai et al. (2019) conducted a 15-month theoretical and practical follow-up assessment after a three-day first-aid intervention in a school in Hungary. The correct hand position was practically assessed (71% correct), the correct compression depth was reported by 27% in the 15-month test, and the compression rate was reported by 20%. The hand position was correctly reported at a similar level in a Slovenian two-year follow-up study in seventh grade. The training period in that study was only 45 minutes (Borovnik Lesjak et al., 2022). In our study, the corresponding values were lower after two years. We found that 51 % reported the correct hand position, 8% the correct compression depth and 7% of the students reported the correct compression rate. Our study included a higher number of cases and multiple schools. What may explain the better results from the students in the study of Banfai et al. (2019), is the shorter follow-up assessment (after four months) and that the students were informed about the assessment a few days before it took place. Our lower results could indicate that for younger students, earlier refresher training (e.g., annually) could be necessary.

In a longitudinal study by Lukas et al. (2016), 261 students in fifth grade were divided into two groups and received annual three-hour training for either three or six years. Both groups were evaluated after six years, but no significant differences in skills or knowledge were found. The three-year annual training group and the six-year annual training group were also divided again into emergency physician vs trainer teacher groups. The arithmetic mean percentage of the correct answers of the knowledge test was 90% after six years, no matter if the training lasted three or six years. If students were taught by a teacher, they received slightly better results in the knowledge test and in the practical assessment of the ventilation (Lukas et al., 2016). The same cohort was examined after four years regarding the starting age of 10 vs. 13 years by Bohn et al. (2012), with the result, that the older students showed higher knowledge throughout all assessments (Bohn et al., 2012).

Brief refresher courses every four months seemed to increase the practical performance in a two-year prospective study in Spain with 472 students aged 8–12 years. Three groups were examined: no refresher course, one refresher training with 50 minutes after one year and very brief (5 min) refresher trainings every four months (Abelairas-Gómez et al., 2021). A relatively large German study with 1,657 teenagers and young adults from six different cities using six different first aid training concepts showed that even with different concepts and a very short training period of 90 minutes per year a good knowledge retention after three years can be achieved in this age group. Almost 90% of the students knew the correct compression point and 77% knew the correct compression rate (Felzen et al., 2021). In our study in a younger age group, the knowledge retention was at a much lower level, which would indicate superiority of shorter intervals between refresher trainings (Abelairas-Gómez et al., 2021). Since we could not evaluate the 5^th and 6^th grade, it is also possible, that this older age group would have answered similarly to the results of the other studies with older students (Bohn et al., 2012; Felzen et al., 2021).

Despite federal legal recommendations by the 16 German state ministries for education and cultural affairs in 2014, comprehensive first aid training has only been implemented in two federal states (Baden-Württemberg and Bavaria) in 2024. In other German states, CPR is part of the curriculum (e.g. in Mecklenburg-Western Pomerania), but training is not implemented throughout the whole state (yet) (Humbsch et al., 2025).

Using teachers as instructors for first-aid trainings in secondary schools was also part of the “Herzensretter” Project (English: Heart Saver) in Brandenburg, Germany. The evaluation showed that even after a 90-minute resuscitation course taught by specially trained schoolteachers may improve short term knowledge and skills, i.e., after one month. However, the project did not include a long-term evaluation (Kehlert et al., 2024).

In a qualitative study, German secondary-schoolteachers were asked about their obstacles of implementing and teaching first aid to their students. Half of the teachers interviewed were BLS-trained. Important factors that the teachers emphasized were the need for practical training and deeper knowledge before teaching it to students, the lack of time in the busy schedule for the year, the need for teaching and training equipment and the need for a room big enough for practical exercises (Dumcke et al., 2024).

The strengths of our study included the relatively large number of students from six different schools and the same rather rural background. Furthermore, the school system with six years of primary school in the German state of Brandenburg (as opposed to only four years in many other states) made it possible to assess the knowledge of students from grades 1 to 4 in a follow-up assessment after two years. We used a similar self-report questionnaire immediately after the training course two years before (Humbsch et al., 2023). Only the compression point was assessed differently. Whereas immediately after the course, an open question was used, in the follow-up assessment and the control group’s assessment, we used a sketch of the human body, where the students had to mark the position of the compression point.

Additionally, our study contributes to filling the research gaps in younger age groups. So far, the great majority of studies in the domain of first aid education have focused on students ages 12 or older. However, the ILCOR scientific statement recently emphasized the importance of starting to teach children earlier in life, even as young as 4 years of age (Schroeder et al., 2023).

However, our study also had several limitations. Firstly, a major limitation in our study was the lack of randomization to a control and an intervention group. Thus, we cannot exclude a possible selection bias. Schools showed interest in first aid trainings and contacted the volunteer organization Pépinière. So, it is possible that only the more dedicated schools applied. Secondly, due to our anonymous approach, the data of the students in the intervention group could not be matched individually between the two assessment time points. This was another important limitation but had to be done to reduce data protection issues and increase parental consent in general. For the analysis, the students in each group had to be considered statistically independent, even though they were mostly the same students in the follow-up and the baseline group. Thirdly, we did not examine whether previous first-aid situations or experiences led to a stronger interest in first-aid topics and perhaps better results. Fourthly, there was no previous evaluation of the students in the control group two years prior to when we enrolled them in the present evaluation, since the schools were recruited later for comparison.

Fifthly, it was unclear what role the socioeconomic status of the families played since primary school students were too young to know this about their parents. Sixthly, although we included several schools from various regions in the state of Brandenburg, our results may not be generalizable to other German states or more urban areas. Seventhly, our questionnaire assessment was labelled as a survey about “important health related topics;” however, the principals of the schools knew what the real purpose was. Thus, we cannot eliminate the possibility that the teachers might have revised first-aid measures to prepare their students. Eighthly, there was no practical exam in the follow-up assessment as compared to the assessment immediately after the course. Thus, we could not assess whether the students may have performed better practically than they did theoretically (as was shown in the previous evaluation immediately after the course).