Lyme disease cases have risen more than 20% in England in the past year, according to public health experts. Pharmaceutical companies are now working to develop new vaccines and drugs to tackle the tick-borne illness.
Rise in Confirmed Cases
Data from the UK Health Security Agency (UKHSA), published in its One Health vector-borne disease surveillance report, shows there were 1,168 laboratory-confirmed cases of Lyme disease in 2025. This is up from 959 in 2024, representing a 22% increase. However, the figure is similar to 2023, when 1,151 cases were confirmed.
Additionally, two probable cases of tick-borne encephalitis complex were identified in 2025, bringing the total number of locally acquired cases to six since 2019, when the virus was first detected in the UK.
Expert Commentary
Dr. Claire Gordon, head of the rare and imported pathogens laboratory at UKHSA, stated: “While the number of laboratory-confirmed acute cases of Lyme disease in 2025 is an increase on numbers reported in 2024, we expect overall case rates to vary year to year depending on awareness, testing rates, and factors that impact outdoor activities such as weather. Broader trends in 2025 remain consistent.”
Lyme disease is caused by the bacterium Borrelia burgdorferi, which lives in the gut of ticks. These tiny, spider-like creatures are found in grassy and wooded areas and feed on the blood of birds and mammals, including humans.
“In recent years, we have seen an increasing geographical distribution of ticks across the UK,” Gordon added. “But tick numbers continue to vary due to changes in weather conditions, climate trends, habitat changes, and shifting host populations.”
Symptoms and Prevention
Symptoms of Lyme disease can include a bullseye-like rash, fever, muscle and joint pain, and lethargy. If left untreated, the condition can become chronic. Even among those who receive antibiotics, some report ongoing symptoms.
Not all ticks carry Lyme bacteria, and rapid removal of ticks reduces the risk of infection after a bite. While various medications are available to protect pets from Lyme disease, including monthly oral tablets and vaccinations, advice for humans focuses on prevention. This includes using repellents, covering exposed skin outdoors, and wearing light-coloured clothing to make ticks easier to spot.
Vaccine Development
Linden Hu, a professor of immunology at Tufts Medical School, explained why veterinary and human approaches differ. Pet owners are often more willing to medicate their dogs than themselves or family members, and clinical trials in humans are harder to conduct.
“It’s easier to do studies in animals because you can control the situation. You can put infected ticks on them to test if it’s going to work, which you really can’t do with humans,” he said. He added that real-world studies, or field trials, are expensive and risky, given the uncertainty of how many Lyme cases will occur.
A human Lyme vaccine called LYMErix was previously available in the US, with trials suggesting 76% efficacy after a third dose. However, it was withdrawn from the market in 2002 due to poor uptake. Hu noted that the US Centers for Disease Control and Prevention recommended it only for high-risk individuals, and concerns about a potential link to arthritis, though unproven, led to negative media coverage and low demand.
Several new treatments are in development. Moderna is working on an mRNA vaccine, which Hu has contributed to and is in phase 2 clinical trials. Pfizer and Valneva are also developing a different vaccine. Crucially, both approaches aim to avoid activating the immune pathway that some researchers suspect caused arthritis in certain recipients of LYMErix.
However, progress has not been smooth. In the Pfizer/Valneva vaccine trial, fewer than expected Lyme cases occurred among participants in a phase 3 trial. While the vaccine appeared to have over 70% efficacy, the results were not statistically robust. Despite this, the vaccine is to be submitted to regulatory authorities.
Alternative Approaches
Other strategies are being explored. Tonix Pharmaceuticals is developing a monoclonal antibody that could be given before tick exposure. Hu is also working with Tarsus Pharmaceuticals on a drug called lotilaner, already used to protect dogs and cats. Unlike vaccines, lotilaner kills ticks rather than the bacteria they carry. According to Hu, it works rapidly by killing ticks before they can transmit Lyme or other diseases.
Public Perception
Julia Knight of the charity Lyme Disease UK said it is unclear whether a vaccine would be adopted in the UK. Official figures for Lyme disease appear low, but they are likely higher because they do not include the roughly 70% of people with Lyme who develop the telltale rash and are treated immediately without laboratory tests. Additionally, Lyme disease can be missed or misdiagnosed.
“Obviously any advances in science that prevents Lyme disease is always welcome, but whether people will welcome a vaccine or not in the current climate of vaccine hesitancy remains to be seen,” she said.
