It is impossible to state, in medicine or any scientific endeavour, that there is absolutely no risk, simply because it is impossible to adduce the evidence to prove the veracity of such a statement. But the press conference held yesterday by the Minister for Health, Mr Martin, to discuss the discovery that a batch of human serum albumin (HSA) might have been contaminated by the prion protein which causes Bovine Spongiform Encephalopathy (BSE), went as near as is logically or scientifically possible to demonstrate that there is no risk in this case. The albumin was used in this instance for the preparation by the English pharmaceutical company, Evans/Medeva, of batches of oral polio vaccine of which 83,500 doses were administered in this State between January 15th 1998 and January 30th 1999.
What triggered the commendable press conference was the recent discovery that one unit of blood, among the pool of 22,353 such donated units used to prepare the batch of albumin in England, had been donated by a man who was subsequently diagnosed as having variant Creutzfeldt Jacob Disease (vCJD) - the human brain disease which may result from the eating of BSE-contaminated beef. That one unit in the original 22,353, was further diluted to one in 63,866 when a further batch of albumin was added during the manufacturing process.
But more compelling evidence of the ultimate safety of the vaccine administered here comes from the complex purification processes which are used in the extraction of HSA from donated blood plasma. These processes are designed to eliminate all protein molecules apart from those of the albumin itself and recent studies of the various plasma fractions have shown no signs of infectivity by "foreign" proteins in the albumin itself.
Most of the doses of the vaccine in question here were given to young children in their routine vaccinations at two, four and six months and in the booster doses at the age of entering primary school. Some adults may also have received doses in the course of getting immunisations prior to foreign travel. While none of the recipients, nor their parents, need experience any personal anxiety as a result, there is a vocal minority in the country which appears to see nothing but danger in the administration of any of the many vaccines which confer protection against several dangerous diseases. This minority tends increasingly to jump on whatever passing anti-vaccine bandwagon may trundle across the radio talk-shows or the correspondence columns of the national newspapers.
But this vocal minority speaks with no medical authority and, apparently, with no understanding of the difference between rumour and scientifically-verifiable fact. The great merit in the press conference called yesterday by the Minister and his Department (attended and supported also by several significant experts in the field of immunisation and related matters) is that it may serve to spike some of the misdirected guns of the anti-vaccine minority and thus relieve many parents of unwarranted anxiety.