Lyme disease in Poland in 2023

Lyme disease is a vector-borne disease transmitted by ticks of the Ixodes genus, caused by a heterogeneous group of Borrelia burgdorferi sensu lato. Human infection occurs through a tick bite and its feeding on the skin. Due to the diverse symptoms, diagnosing Lyme disease is challenging and usually involves a two-step serological approach. Currently, there is still no vaccine against Lyme disease, but in 2024, data on the immunogenicity and safety of the VLA15-221 vaccine, which is in the second phase of clinical trials, was announced.

The aim of the study is to discuss the epidemiological situation of Lyme disease in Poland in 2023 compared to previous years.

To assess the epidemiological situation of Lyme disease in Poland, data sent to NIPH NIH - NRI by the district Sanitary-Epidemiological Stations and published in the annual bulletin: "Infectious diseases and poisonings in Poland in 2023" were used.

In 2023, there were 25 285 reported cases of Lyme disease and 1 155 hospitalizations. This represents a significant increase in cases by 45.58% compared to the previous year. Seasonal variations in case occurrences are evident in distinct quarters, with the number rising from 2 466 in Q1 to 11 626 in Q3, and then declining in Q4 to 5 945. The highest incidence was recorded in the Małopolskie voivodeship (122.9 per 100,000), Podlaskie voivodeship (96 per 100,000), and Warmińsko-Mazurskie voivodeship (95.2 per 100,000).

The number of borreliosis cases returned to pre-pandemic levels but also increased by 22.57% compared to 2019 (20 630 cases), and doubled (95.49%) compared to 2020 (12 934 cases). Seasonality has remained unchanged for years. Usually, eastern Poland (most often the Podlaskie voivodeship) is characterised by the highest incidence, however, in 2023, the highest incidence was recorded in the Małopolskie voivodeship at 122.9 per 100,000.