A small number of cases of complex regional pain syndrome following vaccination have been reported to the TGA ( Therapeutic Goods Administration ).
Health professionals are advised to be mindful of the potential for this adverse event when administering vaccinations.
Complex regional pain syndrome ( CRPS ) is characterised by continuing pain that is disproportionate to any potential inciting event, when accompanied by sensory, motor, vasomotor and sweating/oedema signs and symptoms.
There are two forms of CRPS, type 1 ( CRPS-I ) and type 2 ( CRPS-II ). CRPS-I is more common and describes a situation in which the patient does not have demonstrable nerve injury.
CRPS-II tends to be more serious and describes a situation in which the patient has confirmed nerve injury.
While the cause of CRPS is unknown, it has been diagnosed after trauma, infection, surgery, cervical radiculopathy and myocardial infarction, as well as following vaccination.
The TGA has received five adverse event reports following vaccinations that are consistent with CRPS. Three of those cases involved a human papillomavirus vaccine. Of the other two reports, one involved an influenza vaccine and the other related to diphtheria tetanus acellular pertussis vaccination. Some other reports that listed CRPS as an adverse event did not meet the diagnostic criteria.
As part of a recent review of CRPS following vaccination, the TGA referred the issue to its Advisory Committee on the Safety of Vaccines for consideration.
The Committee noted that cases of CRPS were hard to capture, as there was a large variation in causes, but advised that CRPS following vaccination would have been triggered by the pain caused by the process of immunisation, rather than the contents of the vaccine itself.
Three cases of CRPS involving human papillomavirus vaccine in Australia were examined in an article in 2012, which found that intramuscular immunisation is sufficient painful stimulus to trigger the development of CRPS-I, and that it is the process of a needle penetrating the skin that is the trigger, rather than a particular vaccine antigen or adjuvant being causally related.
Given that all vaccines had the ability to cause some degree of trauma, the Advisory Committee on the Safety of Vaccines deemed CRPS following vaccination was under-reported in Australia.
Following consideration of Australian and international data, the TGA review has concluded that CRPS following vaccination with any vaccine is a very rare event. However, there may be under-diagnosis and/or under-reporting of this adverse event in Australia.
Source: TGA - Medicines Safety Update, Volume 5, Number 3, 2014