As climate change drives the spread of Lyme disease carrying ticks across new areas of the Northern Hemisphere, we still have no human vaccine against the infection. Neither is there a medical consensus about the existence of “chronic Lyme disease”, the symptom complex that some sufferers experience even after being treated for the initial infection.
Lyme disease, or Lyme borreliosis is a bacterial infection of Borrelia burgdorferi spread to humans by infected tick bites. The bite can leave a bulls-eye shaped rash and initial infection causes fever, headache and exhaustion. If left untreated, Lyme disease may develop over several weeks, months or years, leading to inflammatory arthritis, heart problems, issues of the nervous system and even meningitis.
Lyme borreliosis is the most common disease spread by ticks in North America and is estimated to affect at least 65,000 pe-
ople a year in Europe alone. The autopsy of Ötizi the Iceman, a 5,300 year old mummy found in the Ötztal Alps between Austria and Italy discovered the DNA of Borrelia burgdorferi, making him the earliest known human to have suffered from Lyme disease,
Since 2001, cases of Lyme disease in the UK have increased ten-fold. In the US, the Centres for Disease Control has called the increased incidence of infection “a major US public health problem”. This seems to be linked to the warmer winters we have been experiencing over the last decade.
As global warming increases world average temperatures, Lyme disease is spreading outside of its usual territories. Whilst those who live in Lyme disease zones are aware of how to avoid contact with ticks, the spread of the insects to new areas means those less familiar with tick awareness will begin to encounter the disease.
When a tick initially bites, it is only the size of a poppy seed and some people do not display the typical “bulls-eye” rash that would otherwise signify infection with Lyme disease. Likewise, initial flu-like symptoms are easily misdiagnosed and because antibodies to Lyme disease can take weeks to develop, early tests may miss it.
The best approach to combat Lyme disease would be vaccination of those at risk, and in 1998 GSK released Lymerix, an FDA approved human vaccine against Borrelia burgdorferi. However, some recipients of this vaccine claimed it had caused them to suffer autoimmune arthritis, and lead by pressure from various anti-vax groups, Lymerix was withdrawn from the market.
The FDA has since confirmed there was no link between the Lyme vaccine and any autoimmune side effects, but the damage to the vaccines image was done and Lymerix was declared unmarketable by GSK. There are, however, various animal-approved vaccines for Lyme disease, so most farm animals and pets are protected.
The French biotech company Valneva is working on a new human Lyme vaccine that will improve on Lymerix by immunising recipients against all five strains of the disease, however it is still only in the early stages of human trails.
In the meantime, if you plan on hiking in a “high risk” area, such as the North York moors, read up on your anti-tick precautions. Lyme disease can be treated with a two or four week course of antibiotics, and if you suspect you have been bitten by a tick you should seek medical advice.