CDC downgrades estimates of PTLD

Mary Beth Pfeiffer of The Huffington Post continues to follow developments in the Lyme disease saga with this latest blog.

This focuses on the revised (reduced) estimate of Post Treatment Lyme Disease (PTLD) by the CDC in the USA. It seems that this revised incidence of post-treatment symptoms has been based on long-term follow-up of a limited number of early cases, diagnosed at the erythema migrans (EM) rash stage. This approach skews the results in favour of a reduced incidence for PTLD whilst raising the intriguing issue of “false precision”. The motivation for this is unclear.

In Europe papers continue to be published showing a considerable disease burden of Lyme borreliosis(LB) and continuing symptoms after treatment. We know that people treated at the EM stage have a good recovery but that many people treated late have continuing symptoms. van den Wijngaard et al(1) published a significant paper in 2015 and reported that LB has a substantial disease burden

“The disease burden is predominantly due to patients with persisting symptoms attributed to LB”.

They concluded that

“Further research should focus on evaluating the effectiveness of prevention and control measures to reduce the disease burden, and especially on the mechanisms of developing persisting symptoms that patients and their physicians attribute to LB.”

A systematic review published in 2016 stated “LNB patients may experience residual symptoms after treatment with a prevalence of approximately 28 %” (2). It is acknowledged that the percentage affected does depend on whether the patients had possible, probable or definite LNB.

Research often uses the SF-36 questionnaire, and there is some thought that although this may help assess quality of life, it doesn’t necessarily reflect symptoms. For example, the normal population sometimes suffers from aches and pains, fatigue and sleep disruption, but this is altogether different from still suffering with some neurological pain and paraesthesia which started with LNB.

A true estimate of the number of people with continuing symptoms after treatment is important because it determines how much money will be put into research to find the cause. If few people suffer, not much money will be channelled but if it really is a significant number, then it is clearly worth research to find reasons and possible treatment.

As always, the fate of people affected hangs on the measurements used and the accuracy of the reporting.


  1. van den Wijngaard CC, Hofhuis A, Harms MG, Haagsma JA, Wong A, de Wit GA, et al. The burden of Lyme borreliosis expressed in disability-adjusted life years. Eur J Public Health. 2015 Jun 16;
  2. Dersch R, Sommer H, Rauer S, Meerpohl JJ. Prevalence and spectrum of residual symptoms in Lyme neuroborreliosis after pharmacological treatment: a systematic review. J Neurol. 2016 Jan;263(1):17–24.