Seroprevalence, seroconversion and seroreversion of Borrelia burgdorferi-specific IgG antibodies in two population-based studies in children and adolescents, Germany, 2003 to 2006 and 2014 to 2017

BACKGROUND: Lyme borreliosis (LB), caused by Borrelia burgdorferi (Bb), is the most common tick-borne infection in Germany. Antibodies against Bb are prevalent in the general population but information on temporal changes of prevalence and estimates of seroconversion (seroincidence) and seroreversion are lacking, especially for children and adolescents. AIM: We aimed at assessing antibodies against Bb and factors associated with seropositivity in children and adolescents in Germany. METHODS: We estimated seroprevalence via two consecutive cross-sectional surveys (2003–2006 and 2014–2017). Based on a longitudinal survey component, we estimated annual seroconversion/seroreversion rates. RESULTS: Seroprevalence was 4.4% (95% confidence interval (CI): 3.9–4.9%) from 2003 to 2006 and 4.1% (95% CI: 3.2–5.1%) from 2014 to 2017. Seroprevalence increased with age, was higher in male children, the south-eastern regions of Germany and among those with a high socioeconomic status. The annual seroconversion rate was 0.3% and the annual seroreversion rate 3.9%. Males were more likely to seroconvert compared with females. Low antibody levels were the main predictor of seroreversion. CONCLUSION: We did not detect a change in seroprevalence in children and adolescents in Germany over a period of 11 years. Potential long-term changes, for example due to climatic changes, need to be assessed in consecutive serosurveys. Seroconversion was more likely among children and adolescents than among adults, representing a target group for preventive measures. Seroreversion rates are over twice as high in children and adolescents compared with previous studies among adults. Thus, seroprevalence estimates and seroconversion rates in children are likely underestimated.