The Science and Technology Committee has warned that more action is needed to ensure that Variant CJD (vCJD) is not inadvertently transmitted from person-to-person through medical procedures.
Andrew Miller MP, chair of the Science and Technology Committee, commented: “vCJD is a terrible disease and thankfully cases are now rare. However, research suggests that around one in 2,000 could be unknowingly carrying the infectious prions responsible for the condition. This raises the worrying prospect that these prions could be transmitted to others via blood transfusions and other medical procedures.
“There remains significant uncertainty about the magnitude of this risk and the Government therefore claims to be taking a precautionary approach. But our inquiry has shown that its attitude towards vCJD today is far less precautionary than it was in the past. Indeed, recent policy seems to have been driven less by precaution than by economic prudence and a hope that the storm has now passed. This optimism is not supported by the available evidence."
The Committee warned that contaminated surgical instruments are a potential source of ‘prion transmission’; however, evidence to the inquiry suggests that Government guidance on preventing prion transmission may not have been fully implemented across the NHS.
According to figures published by Public Health England, 43 incidents occurred between January 2010 and March 2013 in which surgical patients may have been exposed to CJD as a result of infection control guidance not being properly followed. In many cases this was because the infected patient was not diagnosed with CJD at the time they underwent surgery and enhanced infection control was therefore not deemed necessary. However, in the light of the long period during which people may be ‘silently’ infected, the Committee has recommended that the Government take a more precautionary approach to mitigating this risk.
The Committee commented that Ministers must work with the National Institute of Health and Care Excellence (NICE) and the Advisory Committee on Dangerous Pathogens to assess the extent to which precautions are being taken in hospitals and come up with a plan to improve implementation if preliminary findings prove that compliance is unsatisfactory. The Committee has also recommended greater support for technologies potentially capable of more effectively decontaminating surgical instruments.
Andrew Miller added: “The Government acknowledges that standard decontamination treatments are ineffective in removing prions from surgical instruments. The Government's response to this threat has been insufficient. It has failed to support development of a technology capable of eliminating this risk and instead chooses to rely on guidance which it knows is only partially effective.”
Evidence presented to the inquiry also suggests that the health service cannot be confident that prions are not present in the blood supply. To date, there have only been four confirmed cases in which vCJD is known to have been transmitted via blood transfusion. All of the implicated transfusions are thought to have occurred in the 1990s; however, concerns were raised during the inquiry that asymptomatic prion transmission could still be widespread and could potentially lead to further cases of transfusion-transmitted vCJD in the future.
Andrew Miller commented: "We know that vCJD can be transmitted via blood transfusion because it has happened in the past and we have reason to believe that prions may still be present in the blood supply, so there is a chance that it could happen again. However, in the absence of are liable vCJD blood screening test, we are unable to discard those donations that might be dangerous.
“In our view, the Government could be doing more to help mitigate this risk of infection. Key steps would be for it to reduce uncertainty by supporting relevant research, for example by using the prototype blood test developed by the MRC prion unit in a large-scale study to better understand the rate of ‘silent infection’ across the UK donor pool."
The report recommends that the Government commission a full assessment of the risks currently faced by the UK blood supply so that knowledge gaps can be filled and additional risk reduction measures and technologies developed as appropriate.
Image Credit: CDC_Sherif Zaki MD PhD, Wun-Ju Shieh MD PhD MPH
