P-1287. Incidence of Symptomatic Lyme Borreliosis in Nine European Countries, 2018−2022
Authors: Angulo Frederick , Colby Emily , Fingerle Volker , Lebech Anne-Mette , Lindgren Per-Eric , Moniuszko-Malinowska Anna , Strle Franc , Olsen Julia , Brestrich Gordon , Vyse Andrew , Shafquat Madiha , Gould L Hannah , Kelly Patrick , Pilz Andreas , Halsby Kate , Moisi Jennifer , Stark James H 
Published: January 2025

Abstract

Background
Lyme borreliosis (LB) is the most common tick-borne disease in Europe. Many European countries conduct LB surveillance. However, many symptomatic Bbsl infections are not detected by surveillance. The aim of this study was to estimate the incidence of symptomatic Borrelia burgdorferi sensu lato (Bbsl) infection, including cases not detected or reported by LB surveillance.

Methods
Seroprevalence studies of anti-Bbsl antibodies published in 1998−2023, along with estimates of the symptomatic proportion and persistence of antibodies among Bbsl-infected individuals from studies published in 1990−2023, were used to estimate the incidence of symptomatic Bbsl infection. This incidence was then compared to the incidence of surveillance-reported LB to derive country-specific multipliers and estimate the incidence of symptomatic Bbsl infection from 2018−2022.

Results
Seroprevalence and LB surveillance data were available in nine countries; the prevalence of individuals with anti-Bbsl IgG antibodies ranged from 2.3% in Romania to 9.4% in Germany (Table 1). The pooled estimate of the symptomatic proportion among Bbsl-infected persons from five studies was 37% (95% confidence interval 28%­­−46%). There was a wide range (0.4−33.3 years) of persistence of antibodies in seven studies; therefore, a 10-year duration (scenario #1) and 20-year duration (scenario #2) were used for the duration of antibody detection. Under-detection multipliers varied across surveillance systems (Table 2). Under scenario #1, under-detection multipliers were 2.3−10.5 in countries reporting all LB cases and 54.6−772.2 in countries reporting only Lyme neuroborreliosis (LNB) cases. Under scenario #2, under-detection multipliers were 50% lower than the multipliers under scenario #1. Under both scenarios, the incidence of symptomatic Bbsl infection adjusted for under-detection was highest in Finland, Germany, Norway, Poland, and Switzerland, intermediate in the Czech Republic and Denmark, and lowest in Ireland and Romania (Table 3).

Conclusion
After adjustment of LB surveillance data for under-detection, we found a high incidence of symptomatic Bbsl infection in several European countries. Differences in surveillance need to be considered when comparing reported data across countries.

Disclosures
Frederick Angulo, DVM PhD, Pfizer Vaccines: Employee|Pfizer Vaccines: Stocks/Bonds (Public Company) Gordon Brestrich, PhD, Pfizer Vaccines: Employee|Pfizer Vaccines: Stocks/Bonds (Public Company) Andrew Vyse, Ph.D., Pfizer Vaccines: Employee|Pfizer Vaccines: Stocks/Bonds (Public Company) L. Hannah Gould, PhD, MS, MBA, Pfizer: Employee|Pfizer: Stocks/Bonds (Public Company) Patrick Kelly, PhD, Pfizer Vaccines: Employee|Pfizer Vaccines: Stocks/Bonds (Public Company) Andreas Pilz, PhD, Pfizer Vaccine: Stocks/Bonds (Public Company) Kate Halsby, PhD, Pfizer Vaccines: Stocks/Bonds (Public Company) Jennifer Moisi, PhD, Pfizer: Employee|Pfizer: Stocks/Bonds (Public Company) James H. Stark, PhD, Pfizer: Employee|Pfizer: Stocks/Bonds (Public Company)