Cases of Lyme disease in England have increased by more than 20% in the past year, according to data from the UK Health Security Agency (UKHSA). The agency reported 1,168 laboratory-confirmed cases in 2025, up from 959 in 2024, a rise of 22%. However, this figure is similar to the 1,151 cases recorded in 2023.
Two probable cases of tick-borne encephalitis complex were also identified in 2025, bringing the total number of locally acquired cases to six since the virus was first detected in the UK in 2019. Dr Claire Gordon, head of the rare and imported pathogens laboratory at UKHSA, noted that case rates vary year to year depending on awareness, testing rates, and factors such as weather that influence outdoor activities.
Lyme disease is caused by the bacterium Borrelia burgdorferi, which lives in the gut of ticks found in grassy and wooded areas. Symptoms can include a bullseye-like rash, fever, muscle and joint pain, and lethargy. If left untreated, the condition can become chronic. Dr Gordon highlighted an increasing geographical distribution of ticks across the UK, influenced by weather, climate trends, habitat changes, and shifting host populations.
While vaccines and treatments exist for pets, human prevention currently focuses on repellents, covering exposed skin, and wearing light-coloured clothing. Several new human vaccines are in development, including an mRNA vaccine from Moderna and a vaccine from Pfizer and Valneva. Both aim to avoid the immune pathway suspected of causing arthritis in a previous Lyme vaccine, LYMErix, which was withdrawn in 2002 due to poor uptake.
Other approaches include a monoclonal antibody from Tonix Pharmaceuticals. Despite challenges, such as lower-than-expected Lyme cases in a Pfizer/Valneva phase 3 trial, the vaccine is set to be submitted to regulatory authorities.
