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Variant Creutzfeldt-Jakob Disease

– in the House of Commons at 5:27 pm on 18th March 2010.

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Motion made, and Question proposed, That this House do now adjourn. -(Lyn Brown.)

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Photo of Paul Beresford Paul Beresford Conservative, Mole Valley 5:52 pm, 18th March 2010

Thank you for giving me the opportunity to have this debate, Madam Deputy Speaker, which I have been chasing for a wee while, as I suspect the Minister is aware. I apologise to the Minister that she will be the last man standing this evening-that is not a gender mistake but an old saying. I must declare an interest: I am a very part-time dentist, and this matter faintly touches on that. In fact, dentists have been affected to some degree by the recent rules introduced by the chief dental officer.

I should like to do a little scene-setting, to which I expect the Minister to add. Variant Creutzfeldt-Jakob disease is rare at the moment, but it is an incurable, fatal human disease that is caused by protein particles called prions. It causes a spongy degeneration of the brain and ultimately death. As I said, there is no cure. In contrast to the traditional forms of Creutzfeldt-Jakob disease, vCJD seems today to have affected younger patients. Normally, older patients are affected. That at least appears to be the fact with the original causal link with bovine spongiform encephalopathy in cattle. However, that cause seems to have been eradicated, so transmission now is predominantly from individual to individual, through blood transfusions, organs or surgical equipment. It is known that the transmission from human to human through, for example, blood transfusion, is 100 times more efficient than from species to species.

Carriers of vCJD frequently spend their whole lives as carriers without developing the disease or even knowing that they are carrying it. Unfortunately, it is currently not possible to detect carriers, many of whom are almost certainly present in the population of regular blood donors and patients who undergo different forms of surgery. Logically, that means that unless extensive preventive measures are combined with detection, the population of carriers must increase, which potentially creates a devastating hidden time bomb of vCJD in the decades ahead.

The estimate of the prevalence of individuals incubating vCJD today varies from one in 4,000 to one in 20,000. That comes from the Hilton study, which is based on tests on tonsils and appendix samples. Perhaps it is more disturbing that the UK and Ireland almost certainly have the largest per head of population reservoir of that prion in the world. That explains why UK citizens and even tourists who have visited the UK are not acceptable as blood donors in many countries. It is thought that the incubation period of vCJD is decades. Indeed, if it is like kuru, a similar disease found in Papua New Guinea, it could have an incubation period of up to 40 years from the time of exposure to onset of symptoms. Regardless of the prevalence, it is almost certain that this country will have a considerable number of cases in years to come.

To make matters worse, because vCJD is so difficult to detect, it is fairly certain that the Hilton study was not 100 per cent. accurate or effective in detecting incubating cases. Having very briefly and in simplistic terms set the scene, it is important now to turn to what the Government can and should be doing to combat this potential disaster which will hit our children and grandchildren. Obviously, it would be absolutely fantastic if a cure could be developed tomorrow and an early step made towards a detection method. I hope that Government funding is being made available for that. However, I suspect that we are a long way off from either a cure or a detection method, and prevention of transmission is the utmost priority. Indeed, it is the only thing that we can do at the moment.

With the removal of mad cow disease, transmission now is from individual to individual via blood. The Government have a blood safety advisory body called the Advisory Committee on Safety of Blood, Tissues and Organs, or SaBTO for short. In 1998, leucodepletion was introduced by the UK blood service as a first step in reducing variant CJD infectivity. That process filters blood destined for blood transfusion and removes white blood cells. It was a very useful first step, but at best it only provided a 40 to 70 per cent. reduction in infectivity of donated blood.

In July 2009, SaBTO recommended that UK-sourced blood plasma should not be used for transfusion and should be replaced with plasma sourced from other countries with a much lower risk of variant CJD. However, in October the committee recommended the use of a recently developed prion filtration system. That has been produced by MacoPharma, a medical device technology company. The filter is called a P-Capt filter and has been designed specifically to work directly with the existing technologies used by the UK blood service. It has been CE marked since 2006, some four years ago. This means that it has passed EU safety and efficacy testing, as required for it to be legally used in the United Kingdom.

The filter has been under review by the predecessor committee to SaBTO since 2004 and also by SaBTO since its formation in January 2008. In October 2009, SaBTO recommended several changes. First, it accepted that there was a recognition that further measures to protect the UK blood supply and prevent the spread of variant CJD through blood transfusions should be introduced. Secondly, it said that there was "now sufficient evidence" that the P-Capt prion reduction filter "reduces infectivity" and successfully cleans blood to remove the infective prions that carry variant CJD.

Next and most significantly, the committee recommended that the P-Capt filter should be introduced for filtering the red cells that will be given as blood transfusions to those born since 1 January 1996, with the rider that that should be subject to the completion of the PRISM-platelet receptor inhibition for ischemic syndrome management-trials. The fourth recommendation was that the requirement for prion filtration should be reviewed in the event that further data on variant CJD prevalence or filter efficacy became available. Although I recognise that the logistics and finance need to be fully assessed, to my mind this is an absolute must and requires considerable urgency. Personally, I see it as a first step towards filtering all blood from all donors. There is absolutely no reason why these initial steps should not be implemented immediately and the PRISM trial continued alongside. Hand in hand with this approach, the Department of Health has introduced other measures in other areas, and I give it credit for doing so.

The other logical means of transmitting the prion is surgery, especially with re-used stainless steel equipment, even if it is sterilised. This concern arises from the fact that the prion is extremely difficult to remove from stainless steel and can often survive standard autoclave sterilisation. Even so, when I discussed this with Professor Pennington, who is an expert on the subject, in October 2007, he pointed out that there was no evidence at that time of iatrogenic transmission. That, I suspect, is down to the fact that it is extremely difficult to find the prion and to get any evidence, certainly in the short term.

Motion lapsed (Standing Order No. 9(3)).

Motion made, and Question proposed, That this House do now adjourn.- (Lyn Brown.)

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Photo of Paul Beresford Paul Beresford Conservative, Mole Valley 6:00 pm, 18th March 2010

I suspect that the reason for the professor's opinion is that it is extremely difficult to detect the prion. However, there is a feeling-correctly-that the precautionary principle should be applied, although hopefully in a sensible manner.

With that in mind, I draw the Minister's attention to the decision in April 2007 by the chief dental officer that dentists should not reuse endodontic reamers and files-by that, I mean single-patient use. This, I understand-I may be corrected-was derived from research on mice that were particularly susceptible to variant CJD. The basis of this thinking is that the removal of the prion from stainless steel reamers is difficult, as I think we all accept. Stainless steel reamers are cheap and so not a particular economic problem, even for dentists claiming that their fees are not large enough.

Nowadays, however, most endodontists, or those doing serious amounts of endodontics, are using nickel titanium reamers. A number of specific designs are used in different techniques. Reputable nickel titanium reamers are expensive. I also understand that cleaning the prion off nickel titanium is much easier than taking it off stainless steel. Treatment for a tooth that needs endodontic treatment is therefore made very much more expensive. It is time-consuming if done properly, especially if molar root canal is involved. The unit of dental activity award for molar root canal is small, especially when compared with the alternative treatment, which is extraction using-surprise, surprise-stainless steel forceps, where the same prion difficulty would apply. That might explain the apparent increase in NHS extractions and reduction in NHS endodontics-I expect a letter from the British Dental Association telling me I am wrong.

A number of questions arise. Many stainless steel instruments and burs are used in dentistry, including forceps. If the research on these susceptible mice was so conclusive, one questions why the chief dental officer chose those reamers and whether he thought about extending his ban further. Of course, if he did, he would have to face the problem of probability versus application of the ban versus cost. Should the ban apply only to stainless steel reamers? Should it not be applied to nickel titanium? In 2007 D-Gen and DuPont produced a new prion disinfectant called RelyOn prion inactivator to remove or de-activate the prion on instruments. I would be interested if the Minister could tell me-if not tonight, certainly in a letter-whether that product has been tested, because if so, it would be sensible to introduce its use into the new onerous disinfection and sterilization regulations that dentists are now facing, before the regulations are finalised. That would be better than landing it on a beleaguered dental practitioner after he has installed the equipment for major changes that are coming through.

In 2001, the Department of Health allocated £200 million to modernise NHS surgical decontamination, along similar lines to that descending on dentists now. Attempts have been made to produce single-use instruments for some surgery, and I understand that plastic instruments were developed for tonsil surgery but proved a failure. New rules have also been brought in on contact lenses, and it would be interesting to see whether those would be applicable or useful.

However, the way forward has to be blood transfusion filtering. Some 1.8 million blood units are donated in the UK annually, and SaBTO has recommended the immediate P-Capt filtering of all blood for children. In the Prime Minister's letter to me, on 11 February, following my question on this subject, he said that the introduction of the filter should be subject to the satisfactory completion of a clinical trial. I assume that he was referring to the ongoing-long ongoing-PRISM study. I understand that the study is way behind schedule. There are previous studies-I can draw the Minister's attention to them, if they are not in her notes-and, as I have said, the filter has a CE mark.

I ask the Minister to move now on blood filtering, initially for children and then for all. If it is good enough for the Department of Health to use the precautionary principle for endodontic files after questionable thought, the same principle should be applied to blood transfusion filtering. Action on endodontic files is essentially fiddling around the edges. Blood transfusion filtering is central to reducing or stopping blood transfusion transference of prions, to the benefit of future generations. I am sure Health Ministers would not like to be named in what I will call an "If only we had" report in 20 to 40 years, when people are dying from variant CJD.

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Photo of Gillian Merron Gillian Merron Minister of State (Public Health), Department of Health 6:05 pm, 18th March 2010

I congratulate Sir Paul Beresford on securing this debate, and on his thoughtful and well-informed comments. I am glad to have this opportunity to update the House on the latest developments.

We can be thankful that the number of variant CJD cases in this country has so far been relatively low. Every case is serious, however, and devastating for the individuals and families involved. I want to express my deepest sympathy for all those whose lives have been affected by this traumatic and tragic illness. There remains much to learn about the disease. We do not know how many people are potentially infected, and we do not know the maximum incubation period, or how the disease progresses through the body.

The House will recall that the consensus on the origins of this terrible disease, which is fatal, is that people unknowingly ate meat that was contaminated with bovine spongiform encephalopathy. The BSE controls that were introduced from 1989 minimised the risks of infection from cattle. Our focus now is on reducing the risk of person-to-person transmission, and on caring for those who are already infected. I can give the hon. Gentleman the assurance that the Government are currently spending more than £7.5 million on variant CJD surveillance and research every year. It is true, however, that with so many unknowns still surrounding the disease, we must remain both cautious and vigilant. We must follow the evidence, and we must also ensure that any new measures that we introduce are safe and proportionate. These principles underpin everything that we have done on variant CJD.

The hon. Gentleman made a number of important comments about dentistry and about variant CJD. I appreciate that he speaks from a position of rather more personal and professional expertise than I do on this matter. There are no known cases of variant CJD being transmitted through dentistry, but, as the spongiform encephalopathy advisory committee has noted, studies using BSE in mice suggest that there is a potential risk of infection from oral tissue, as the hon. Gentleman suggested. The risk is difficult to quantify, but, given the seriousness of the disease, it is only right that we take precautions, especially when those precautions bring wider, additional benefits.

As the health technical memorandum and the British Dental Association's recent advice sheet on infection control make clear, the risks posed by variant CJD and other infections demand the most rigorous measures to prevent cross-infection. That is why we have issued guidance that encourages the use of automated washer disinfectors, which remove the worst contamination from dental instruments and ensure greater consistency and containment in cleaning. Although the guidance is part of our precautionary approach to variant CJD, it serves a dual purpose by improving overall standards of dental decontamination.

It is important to recognise that the guidance is the result of consultation with the dental profession, and that the British Dental Association was fully involved in its development. It is also important to note that that is just one of the actions that we have taken to manage risks in dentistry. In April 2007, the chief dental officer wrote to all dentists advising them that certain instruments that are difficult to clean should be made single-use. As I mentioned earlier, when it comes to managing risk in dentistry, we must always follow the evidence.

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Photo of Paul Beresford Paul Beresford Conservative, Mole Valley

At almost the moment when that instruction was conveyed to all dentists, the British Dental Journal-the journal of the British Dental Association-published a report which pointed out that forceps posed just as big a danger as files. That is extraordinary. I should be grateful if the Minister would look at some of the comments that I have made about it, and then write to me.

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Photo of Gillian Merron Gillian Merron Minister of State (Public Health), Department of Health

I shall be happy to look at all the comments that the hon. Gentleman has made this evening. I hope that my response will satisfy him, but I shall give further consideration to any issues that require it.

It is because of the importance of following evidence-this may be relevant to what the hon. Gentleman has just said-that we keep all precautionary measures under review, and have commissioned further research on the effectiveness of automated washer disinfectors and the disinfectant agents used in them. We expect the performance of AWDs to improve significantly in the coming years.

The hon. Gentleman raised important issues relating to potential transmission of variant CJD transmission via blood. The safety of blood and blood products used in the NHS is of the highest importance, and we take every reasonable known precaution to cut the risk of transmission. In 1997, we recalled all blood and tissue donated by people who later developed variant CJD. In 1998, we arranged for plasma to be procured from non-UK sources. In 1999, we introduced leucodepletion for all donations, ensuring that white blood cells are removed from donated blood. There have been no reported transmissions from blood treated in that way.

In 2002, we announced that fresh frozen plasma for treating infants and young children would be obtained from the United States and purchased a US-based plasma collection company. In 2004, we announced that people who had received whole blood transfusions since 1980 would no longer be allowed to donate blood, and we introduced new measures to protect patients who had received some plasma products. In 2005, we extended the use of American-sourced plasma to all children up to the age of 16, and started a notification scheme to track people who had donated blood to three individuals who later developed variant CJD. We have also made synthetic clotting agents available for haemophiliacs. I hope that that record demonstrates the Government's commitment to ensuring that at all stages-from procurement and donation to supply and distribution-we have taken every possible action to minimise the risk of variant CJD transmission.

The hon. Gentleman asked about the Government's position on prion filtration. The independent Advisory Committee on the Safety of Blood, Tissues and Organs recently expressed the view that there is now sufficient evidence that a particular filter can reduce potential infectivity in a unit of red blood cells, and has recommended the introduction of filtered blood to treat those born since 1 January 1996. Subject to satisfactory completion of a clinical trial to assess safety, the Government are undertaking an evaluation of the costs, benefits and impacts in order to inform a decision on whether to implement the recommendation. The rationale for the introduction of filtered blood to treat those born before 1 January 1996 is that members of that age group will not have been exposed to BSE by their diet.

We are conducting additional clinical safety trials because, as I have said, we want to ensure-as the House would expect us to-that issues of quality and safety are fully assessed before consideration is given to whether effective prion filtration technologies should be introduced. The clinical studies that have been undertaken so far involve the transfusion of filtered blood into healthy volunteers. Because those studies do not provide enough assurance about the safety of transfusing filtered blood into patients with medical conditions, studies of cardiac surgery and transfusion-dependent patients have been commissioned. I hope that the ongoing trials will be completed by the end of the year. The impact assessment will inform Ministers, who will be interested to look at the evidence.

The hon. Gentleman, a number of other Members and also campaign groups have raised the issue of the calling for routine vCJD testing of blood donors and/or donated blood. Although some blood tests are in development, none of them are currently suitable for use. However, if there were an effective and accurate test, we would, of course, consider it.

On care for vCJD sufferers, although there is no known treatment, the Department of Health has set up services and a care package fund to help patients and their families. The care fund is administered by the national CJD surveillance unit, and it is used to support patients in the community and to pay for those elements of their care that cannot be readily supplied by local health and social services, such as housing adaptation, additional nursing care, and access to an adapted motor vehicle. The fund is available for people with all types of CJD in any part of the UK, and it is not subject to cash limits.

I thank the hon. Gentleman for securing this debate on such an important issue. I hope he will be reassured that we continue to do everything we can to reduce the risk of transmission of vCJD between people and are pursuing a policy that is grounded in practicality and based on evidence. We continue to invest in research that is focused on improvements in decontamination, testing and treatment. We have taken progressive action to reduce the risk from vCJD in the procurement, supply and delivery of blood products. We have developed guidance on surgical and dental instruments, which ensures that cleaning is of the highest technical standard, and which is to be continually audited. We are closely monitoring new clinical developments, whether on filtration or a blood test for vCJD. We also, of course, intend to keep all precautionary measures under review as and when new evidence emerges.

I hope my remarks serve to reassure the hon. Gentleman that this is an open book and that our work is continuing.

Question put and agreed to.

House adjourned.

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