Possible questions regarding Oral Polio Vaccine and Human Serum Albumin/vCJD Issue
What is Oral Polio Vaccine?
Oral Polio Vaccine abbreviated as OPV is a vaccine given to young children in liquid form by mouth to protect them against infection by Polio virus which can cause a paralytic and sometimes fatal illness.
Who gets the OPV used in Ireland?
This vaccine is administered by mouth to children as part of the Childhood Primary Immunisation Programme at the ages of 2, 4 and 6 months and a booster dose is given at entry to primary school.
Some adults may also have received this vaccination as part of immunisation for foreign travel.
Who makes the brands of OPV used in Ireland?
A number of manufacturers make Oral Polio Vaccines: The two companies from the UK who have manufactured the products which have been available on the Irish market in the last number of years are Evans/Medeva and SmithKline Beecham.
What was the problem with this vaccine?
The Irish Medicines Board (IMB) has been informed that a constituent of the vaccine namely human serum albumin (HSA) utilised a blood donation in its manufacture from a UK resident who has recently been diagnosed with vCJD.
HSA is a product which is made from human blood donations. It is a protein (albumin) obtained from blood serum (hence its name). It is used as a stabiliser in some medicinal products and vaccines.
This issue relates only to a constituent known as HSA and sourced in the UK which was present only in the Evans/Medeva product distributed in Ireland between 15 January, 1998 and 30 January 1999.
The manufacture of HSA involves pooling together the plasma from a large number of individual donations. The Department of Health and Children has been informed that one UK blood donor, the plasma of whose donation was used to make a batch of the product human serum albumin, has recently been diagnosed as having the variant form of Creutzfeldt Jakob Disease (vCJD).
This person’s donation was one of 22,353 used to make a pool of plasma. HSA was prepared from this pool and subsequently combined with additional albumin to give a final dilution of 1/63,866.
Is there a risk associated with this event for me or my family?
Expert advice, both national and international, available to the Department of Health and Children indicates that the potential risk, if any, to recipients is essentially non-existent. It is not possible in medicine to state that there is zero risk; however, in this situation, we are confident that it is almost certainly the case.
Albumin has a long tradition of safety. This is based partly on the fact that the purification methods used in its manufacture eliminate the potential for infectivity. Albumin is produced at the last stage of a series of purification procedures. Recent studies of the various plasma fractions have shown no infectivity associated with albumin.
If there is no real risk, why is this information being disclosed at all, and why now?
The Minister has disclosed this information as a precautionary step, and on the basis that the public have a right to have it – even though there is no evidence that recipients of the vaccine are at any risk as a result.
The Minister was also conscious that the information was likely to come into the public domain in any event, and that it was preferable that it be made available with appropriate expert advice and assurances for the public about the issues involved.
Do other medicines also contain HSA?
There are a number of other medicines which also contain HSA. These use HSA obtained from non UK donors.
Are other vaccines affected?
No other vaccines are affected.
No other vaccines in use in Ireland contain UK-sourced Human Serum Albumin. Since January 1999 the Medeva vaccine involved in this issue has not contained UK-sourced HSA. Medeva oral polio vaccine has not been in use in Ireland since September 2000.
What other contact points are there if people are concerned about this vaccine?
In the first instance people who wish to find out if their child or another family member got this vaccine are advised to contact the health professional who gave the vaccine. For infants this will usually be the family doctor. For children receiving a booster immunisation around the time of primary school entry, in most cases the vaccination will have been given by the health board, and inquiries should be directed to the relevant health board.
The Department of Health and Children’s website (www.doh.ie) contains details of the Minister’s statement and a Questions and Answers document. The Irish Medicines Board’s website also contains (www.imb.ie) information on the issues, intended primarily for health professionals
Transmissible Spongiform Encephalopathy (TSE) are a family of degenerative diseases caused by prion proteins which affect animals and humans.
Bovine Spongiform Encephalopathy (BSE) is an animal spongiform encephalopathy which was first diagnosed in the United Kingdom in 1986.
CJD is a rare transmissible encephalopathy in humans. It is the collective name for a group of diseases which cause progressive dementia and a loss of control of movement and balance. There are four types of CJD, which include Variant CJD (NVCJD or VCJD). The overall global incidence of CJD is approximately one case per million per year. However, this has increased in recent years. This increase is most likely due to active surveillance which has been established in many countries as well as improvements in diagnosis.
This is the most common (80%) form of CJD and occurs worldwide. It mainly affects older people and the average age of onset is 65 years of age. The cause of this condition is unknown. The average duration of illness is 5 months and the clinical hallmarks are rapid progression of dementia, together with loss of control of movement. There are an average of 3 cases in Ireland per annum.
Variant CJD (VCJD)
The newly recognised condition was first described in the UK in 1996. There are now approximately 88 cases in the UK, including one case from Northern Ireland, two cases in France and one from the Republic of Ireland. Clinically, these cases present at an early age and are different from Classic CJD The presenting features include behavioural disturbances followed by difficulties with balance and walking. The average survival is approximately 13 months which is longer than the Classic/Sporadic CJD. The confirmation of VCJD is neuropathological.
Relationship between VCJD and BSE
Experimental evidence now indicates that VCJD and BSE are caused by the same agent. Brain tissue from VCJD patients show similar features to animals experimentally infected with the BSE agent.
In relation to the source of VCJD infection, the most likely explanation is the ingestion by humans of BSE-contaminated food prior to the implementation of the ban on specified bovine offals in the human food chain.
Minister Martin issues statement about Polio Vaccine distributed in 1998/9